SERVO ROBOTIC ASSEMBLY - Edl · PDF file · 2017-01-02Computer with Windows XP Operating System Amatrol or School Supplied ... A servo robotic assembly system performs a sequence

LEARNINGACTIVITYPACKETMECHATRONICS

B72001-AA07UEN

SERVO ROBOTICASSEMBLY

B72001-AA07UEN SERVO ROBOTIC ASSEMBLYCopyright © 2012 Amatrol, Inc.

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LEARNING ACTIVITY PACKET 7

SERVO ROBOTIC ASSEMBLY

INTRODUCTIONAutomated assembly systems are key components in many mechatronics systems.

They automatically assemble parts and move them onto the next step in the process. Servo robots are one type of automated assembly system used in mechatronics.

This LAP reviews servo robotic assembly system components, their adjustment, and programming.

ITEMS NEEDEDAmatrol Supplied 87-MS5 Mechatronics Servo Robotic Station 870-PS7313-AAU, 870-PS7314-AAU, or 870-PS7315-AAU Mechatronics Learning System for Siemens S7-300 - one per station 72024 Siemens S7-300 Programming Cable 82-900 Siemens Step 7 Programming Software

School Supplied Computer with Windows XP Operating System

Amatrol or School Supplied 41222 Hand Tool Kit or Equivalent

FIRST EDITION, LAP 7, REV. BAmatrol, AMNET, CIMSOFT, MCL, MINI-CIM, IST, ITC, VEST, and Technovate are trademarks or registered trademarks of Amatrol, Inc. All other brand and product names are trademarks or registered trademarks of their respective companies.Copyright © 2012, 2011 by AMATROL, INC.All rights Reserved. No part of this publication may be reproduced, translated, or transmitted in any form or by any means, electronic, optical, mechanical, or magnetic, including but not limited to photographing, photocopying, recording or any information storage and retrieval system, without written permission of the copyright owner.Amatrol,Inc., 2400 Centennial Blvd., Jeffersonville, IN 47131 USA, Ph 812-288-8285, FAX 812-283-1584 www.amatrol.com


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TABLE OF CONTENTS

SEGMENT 1 STATION OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4OBJECTIVE 1 Describe the operation of a servo robotic assembly systemOBJECTIVE 2 Describe the operation of a pick and place assembly systemOBJECTIVE 3 Describe the operation of a gravity feeder with escapementOBJECTIVE 4 Describe the operation of an automatic screw feeder

SKILL 1 Operate a servo robotic assembly station

SEGMENT 2 COMPONENT ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37OBJECTIVE 5 Describe how to adjust a parts feeder with escapement

SKILL 2 Adjust a parts feeder with escapementOBJECTIVE 6 Describe how to adjust an automatic screw feeder

SKILL 3 Adjust an automatic screw feederOBJECTIVE 7 Describe how to adjust a pneumatic part shuttle

SKILL 4 Adjust a pneumatic part shuttle

SEGMENT 3 MODULE SEQUENCING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53OBJECTIVE 8 Describe a sequence of operation of a part insertion module

SKILL 5 Design a PLC program that sequences a part insertion moduleOBJECTIVE 9 Describe a sequence of operation of a screw feed module

SKILL 6 Design a PLC program that sequences a screw feed moduleOBJECTIVE 10 Describe a sequence of operation of a screw thread engagement module

SKILL 7 Design a PLC program that sequences a screw thread engagement module

SEGMENT 4 STATION SEQUENCING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99OBJECTIVE 11 Describe a sequence of operation of a servo robotic assembly station

SKILL 8 Design a PLC program that sequences a servo robotic assembly stationOBJECTIVE 12 Describe the operation of a servo robotic assembly station with manual/ auto/reset functions

SKILL 9 Design a PLC program that provides manual/ auto/ reset functions for a servo robotic assembly station


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SEGMENT 1STATION OPERATION

OBJECTIVE 1 DESCRIBE THE OPERATION OF A SERVO ROBOTIC ASSEMBLY SYSTEM

A servo robotic assembly system performs a sequence of automated assembly operations to join two or more parts into one assembly. This type of system uses one or more assembly workstations, part feeders, and a robot for component handling.

Figure 1. Robotic Assembly

A typical servo robotic assembly system uses a robot to retrieve parts from other processing stations or from parts feeders and may use it for some of the assembly process. The robot places the parts in the assembly fi xture and then moves to a clear position. Once the robot is clear, the assembly fi xture takes over and performs tasks such as insert fasteners, weld or glue parts together, or install components on circuit boards. The robot may be used to move subassemblies from one assembly module to another. Once the assembly is complete, the robot removes the fi nished part to a storage location or to another station for further processing.


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In a robotic assembly system the robots are often interfaced to other intelligent controllers to enable them to coordinate operations. One common application is a multi-station conveyor system that transports parts to workstations where robots perform tasks to create a product. Typically, a PLC controls the movement of pallets containing raw material on the conveyor, stopping them at various stations.

When a pallet arrives at a workstation, the conveyor PLC sends a signal to the robot controller to tell it to begin operations at the station. When the operation at the station is fi nished, the robot controller sends a signal back to the conveyor PLC to tell it that it has completed operations.

Figure 2. Robotic Assembly System

FINISHEDPRODUCT

FEED

BASE HOUSINGFEED STATION

#1

#2 #3 #4 #5

BEARING INSERT ROTOR ASSEMBLYREAR HOUSING

ASSEMBLYSCREW

FASTENING

VIBRATIONBOWL

FEEDER

PLC CELLCONTROL


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OBJECTIVE 2 DESCRIBE THE OPERATION OF A PICK AND PLACE ASSEMBLY SYSTEM

Pick and place assembly systems use manipulators to lift, move, and place objects in desired locations. These manipulators pick parts from feeders or bins and place them directly on the assembly or in position for assembly by other auto-mated equipment.

The assembly performed by a pick and place system may include placing fasteners, components on circuit boards for surface mount technology (SMT), or applying adhesive for component placement. Once the assembly is complete, the pick and place device typically removes the assembly to a material transfer device or to another station for further processing.

Figure 3. Pick and Place Assembly System

Pick and place assembly systems are typically controlled by a PLC, often using solenoid-operated pneumatic or hydraulic valves to control machine movements, although they can be servo-controlled as well. Because pick and place systems have limited program positions, pick and place assembly systems are used for sequential assembly operations, where each pick and place device performs one step of a multiple step automated assembly process.

2-AXIS MANIPULATORWITH ROTATING GRIPPER

PART HOLDING

TRAYS

ASSEMBLYWORK SURFACE

PART HOLDING

TRAYS


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OBJECTIVE 3 DESCRIBE THE OPERATION OF A GRAVITY FEEDER WITH ESCAPEMENT

Gravity feeders hold parts for use by the assembly process. When the bottom part is removed, gravity causes the rest of the parts to drop down. Some gravity feeders include an escapement, which is a device that allows parts to be fed one at a time into the process.

One example of an escapement is shown in fi gure 4. This escapement uses a fl exible tab to hold back the parts. When the work carriers pass, they catch the bottom of the part with enough force to push it from the feeder into the work carrier. As this occurs, gravity forces the other parts to move down.

Figure 4. Gravity Part Feeder with Escapement

Another example of an escapement is a dual pneumatic cylinder type, shown in fi gure 5. The fi rst cylinder (A) holds the bulk of the parts back. It retracts and releases one part at a time to the second cylinder (B). Once cylinder A is extended again, cylinder B can retract and release the part to the process. This prevents multiple parts from falling into the process. This type of escapement also works well on conveyor-style feeders.

Figure 5. Dual Pneumatic Cylinder Escapement

ESCAPEMENT FEEDTRACK

PARTCARRIERS

PARTS

STEP 1

STEP 2

STEP 3

STEP 4

CYLINDER A

CYLINDER B

CYLINDER A

CYLINDER B

CYLINDER A

CYLINDER B

CYLINDER A

CYLINDER B


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A third example of a gravity feeder escapement is shown in fi gure 6. In this example, the parts are loaded into a gravity feed chute that allows them to drop down one at a time. The bottom part is exposed to the process and held in place by an adjustable ball-nose spring plunger, which acts as stop or holding point. This stop is a form of an escapement. The part is picked from the feeder by a robot. Once that part is removed, the next part drops into place.

Figure 6. Gravity Feeder with Stop Escapement

GRAVITYFEED CHUTE

PART

STOPESCAPEMENT


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OBJECTIVE 4 DESCRIBE THE OPERATION OF AN AUTOMATIC SCREW FEEDER

An automatic screw feeder feeds screws or bolts into a process. One example is the pneumatic valve assembly process shown. Some screw feeder designs may use multiple cylinders to ensure proper positioning of the screws. A sensor is often positioned to read when the feeder is out of parts, sending a signal to the PLC to stop the sequence until more parts are put in the feeder.

Figure 7 shows an example of an automatic screw feed application. This appli-cation uses three cylinders (1, 2, and 3) to restrain and release the screws, which are fed into the system through a vinyl tube fi lled with compressed air. Cylinders 1 and 2 operate the screw guide and restraint mechanism. Cylinder 3 prevents the next screw in line from feeding during the insertion process. Timers in the PLC program controls this process.

Figure 7. Automatic Screw Feeder

SCREWS

CYLINDERS

1 23

PARTSENSOR

FLOW CONTROL VALVES

HOSE

PRESSUREREGULATOR

SCREWFEED CAP

DIALINDICATOR

SCREWREADY TO

BE PUSHEDINTO VALVE

BODY


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Figure 8 shows the operation of the screw feed cylinders. When the system is started, step 1, cylinder 1 is retracted and cylinder 2 is extended, closing the screw guide and restraining the fi rst screw in line in position. A portion of the screw extends beyond the feeder and into the assembly area. Cylinder 3 is also retracted at this time.

When the PLC calls for a screw, step 2, the fi rst screw insertion timer starts and the screw insertion solenoid valve is energized. Energizing the solenoid causes cylinder 3 to extend to trap the second screw in line under the screw head. At the same time, cylinder 1 extends and cylinder 2 retracts, opening the screw guide, as shown in Step 3. At this point, the fi rst screw is partially inserted into the assembly and the second screw is held back by cylinder 3. This is when the fi rst screw inser-tion timer ends and a second timer starts.

The screw insertion solenoid valve is de-energized, shown in Step 4, which sends the screw feed cylinders back to their home positions. Cylinder 1 retracts and cylinder 2 extends to once again close the screw guide and restrain the next screw in line. Cylinder 3 retracts, allowing the next screw in line to move into the screw guide and at the same time push the fi rst screw all the way into the assembly.

Figure 8. Automatic Screw Feeder Operation

CYLINDER 1CYLINDER 2

CYLINDER 3

CYLINDER 1CYLINDER 2

CYLINDER 3

CYLINDER 1 CYLINDER 2

CYLINDER 3

CYLINDER 1

CYLINDER 2

CYLINDER 3

ASSEMBLY

SCREW EXTENDSINTO ASSEMBLYAREA

SCREWGUIDE FIRST

SCREWSECONDSCREW

SCREWGUIDE

CYLINDER EXTENDS TOCATCH SECOND SCREWUNDER THE HEAD

SCREWGUIDEOPENS SCREW HELD IN PLACE

END OF SCREWPUSHES FIRST SCREW INTO ASSEMBLY

SCREWGUIDE CLOSES

SECOND SCREW EXTENDSINTO SCREW GUIDE

CYLINDER RETRACTS

STEP 1 STEP 2

STEP 3 STEP 4


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The screw feeder cylinders are regulated using the fl ow control valves mounted on the cylinders. By regulating each individual cylinder, the speed at which the screw is released and fed into the part is controlled. Some cylinders, such as the ones shown in fi gure 9, are used together to perform one task, so their speed for both extend and retract should always be the same.

Figure 9. Cylinder Pair

1/2 OF SCREW GUIDECONTROLLED BYTOP CYLINDER

1/2 OF SCREW GUIDECONTROLLED BY

BOTTOM CYLINDER

FLOW CONTROLVALVE

FLOWCONTROL

VALVES

CYLINDER 1

CYLINDER 3

CYLINDER 2


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SKILL 1 OPERATE A SERVO ROBOTIC ASSEMBLY STATION

Procedure Overview

In this procedure, you will start up and operate the 87-MS5 Servo Robotic Assembly station of the 870 Mechatronics System.

1. Locate the 87-MS5 Servo Robotic Assembly station, shown in fi gure 10. Your system may have a Pegasus robot, as shown on the left side of fi gure 10,

or a Saturn robot as shown on the right side of fi gure 10.

Figure 10. 87-MS5 Servo Robotic Assembly Station

2. Verify that this station has been separated from any other stations. If it has not, then proceed with Step 3 to separate it from the other station. If it has, then proceed to Step 4.

3. Perform the following substeps to separate the Servo Robotic Assembly station from the other stations.

A. Remove the power cord from the wall outlet.

B. Remove the adjoining unit’s power cord.

C. Remove the adjoining unit’s pneumatic hose.

D. Disconnect the 9-pin to 9-pin cable from the other unit(s).


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E. Loosen the connecting fasteners that hold the work surfaces together by turning the wing nuts CCW.

F. Push the station away from the other stations to give yourself room to work.

Figure 11. 87-MS5 Servo Robotic Assembly Station Separated From Other Stations

4. Perform the following safety check before you begin working on the station. Make sure that you can answer yes to each item before proceeding.

YES/NO SAFETY CHECKOUT

Remove all obstructions from the work area

Check for signs of damage to the equipment

Wear tight fi tting clothing, roll up long sleeves, remove ties, scarves, jewelry, etc.

Tie up long hair

Remove any robot teach pendants from the work area

Locate the emergency stop button

Ensure that safety glasses are worn by people in the area

Ensure that all people are outside any work envelopes

Figure 12. Mechatronics Safety Check


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5. Perform the following substeps to install the Feed Stand. The feed stand is used when the 87-MS5 is separated from the other stations

to hold the valve bodies so the robot can easily pick them up.

A. Obtain the Feed Stand and mounting hardware, (3) 1/4-20 x 3/8-inch button head cap screws and (1) triple T-nut, shown in the top of fi gure 13, from your instructor.

If you have the single feed stand, you will have a double t-nut and (2) 1/4-20 x 3/8-inch button head cap screws, as shown in the bottom of fi gure 13. The installation instructions that follow show the double feed stand, but applies to the single as well.

Figure 13. Feed Stand

DOUBLEFEED

STAND

TRIPLET-NUT

1/4-20X3/8 IN. BUTTON HEAD CAP SCREWS

SINGLEFEED

STAND

DOUBLE T-NUT


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B. Loosen either the front or rear end cap from the left side (as you are facing the control panel) of the work surface by prying it off, as shown in fi gure 14. A screwdriver may be required as the end cap may have a tight fi t.

Figure 14. Loosen the End Cap

C. Slide the triple T-nut along the inside of the aluminum extrusion so that it is positioned in line with the assembly fi xture, as shown in fi gure 15.

Figure 15. Position the Triple T-Nut

TRIPLET-NUT


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D. Position the feed stand as shown in fi gure 16 so the holes in the bottom fl ange line up with those in the triple T-nut.

Figure 16. Feed Stand Position

E. Insert the screws through the outside of the feed stand so that the threads engage the T-nut, and tighten the screws by using a 7/16-inch hex wrench and turning them CW until snug so the feed stand is secure.

Figure 17. Insert Screws

TRIPLET-NUT

BOTTOM OF FEED STAND

FEEDSTAND

BUTTON HEAD CAP SCREWS


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F. Replace the end cap on the end of the work surface.

Figure 18. Mounted Feed Stand

6. Perform the following substeps to install the parts bin, shown in fi gure 19. The parts bin is used when the station is separated from the other stations to

catch the parts as the robot drops them.

A. Obtain the red plastic parts bin, mounting bracket, and (2) 1/4-20 x 1/2” thumbscrews and (2) single T-nuts, shown in fi gure 19.

Figure 19. Parts Bin, Mounting Bracket, and Mounting Hardware

FEEDSTAND

BIN

THUMBSCREWS

T-NUTS

MOUNTING BRACKETS


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B. Loosen the end cap on the right side of the work surface (as you are facing the station) by prying it off, as done in the previous step.

A screwdriver may be required as the end cap may have a tight fi t.

C. Slide the two t-nuts along the inside of the aluminum extrusion so that they are positioned in line with the end of the knob/spring assembly fi xture.

Figure 20. Position the Single T-Nuts

D. Position the mounting bracket so it is in line with the work fi xture, as shown in fi gure 21.

E. Use a screwdriver to position the T-nuts so they are in line with the holes in the mounting bracket.

FIXTUREEXTENDED END OF

TRANSFER CYLINDER

T-NUTS


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F. Insert the thumbscrews through the outside of the bracket so that the threads engage the T-nuts. Then tighten the thumbscrews by turning them CW until snug so the bracket is secure.

The T-nuts have a tendency to angle back away from vertical, so this step may take several tries.

Figure 21. Positioning of Bracket

G. Replace the end cap on the end of the work surface.

H. Attach the parts bin to the top of the mounting bracket.

Figure 22. Parts Bin Mounted to the Mounting Bracket

WORKFIXTURE


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7. Connect an air supply to the station’s air manifold quick connect. 8. Plug the station’s power cable into a wall outlet. 9. Perform the following substeps to power up the 87-MS5 Servo Robotic

Assembly station.

A. Place the Mode Selector switch in the Manual position.

B. Remove the lockout/tagout device from the electrical power source.

C. Remove the lockout/tagout device from the pneumatic power source.

D. Turn on air to the station by shifting the lever on the lockout valve.

E. Set the station’s air supply regulator to 50 psi/345 kPa.

F. Set the screw feed module’s air supply regulator to 12 psi/82.7 kPa.

G. Turn the station’s Main Power switch to the On position. 10. Perform the following substeps to open the PLC programming software.

A. Make sure that the interface from the personal computer to the PLC is connected.

B. Power up the PC and monitor.

C. Start the SIMATIC Manager. 11. Perform the following substeps to open project Robotic Assembly Station.

A. Click the Open Project/Library button.

The Open Project/Library dialog should open.

B. Locate project Servo Robotic Assembly.

The project Servo Robotic Assembly Station was provided on a supple-mental disk.

If it is not listed on the dialog, click the Browse button on the dialog to view the projects located in the S7Proj folder.

C. Double-click the Servo Robotic Assembly icon to open the project.

D. Select Expand All from the View menu to expand the project’s contents.

The option is “Expand All” if using STEP 7 Version 5.2 or “Show All Levels” if using STEP 7 Version 5.3.

NOTE

The air on this station may be loud, so once you set the air supply regulators, you may want to shift the lever on the lockout valve until you reach step 15.


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12. Perform the following substeps to download the project Servo Robotic Assembly to the PLC.

A. Place the PLC’s Mode Selector switch in the RUN position.

B. Reset the PLC.

C. Select the SIMATIC 300 Station object by clicking it so that it is highlighted.

D. Click the Download button to download the project to the PLC.

Several dialogs will appear during the download. Click the appropriate response to continue downloading the program. The last dialog should ask if you wish to perform a complete (Warm) restart.

E. Click Yes on the dialog to complete a warm restart. 13. Perform the following substeps to stock the parts feeders.

A. Obtain from your instructor the screws, spools, and knob/spring assem-blies used in the valve assembly.

B. Remove the cap from the screw feeder, shown in fi gure 23, by turning it CCW.

Figure 23. Screw Feeder Cap

C. Insert the screws thread side down into the feeder.

D. Place the cap back on the screw feeder by turning it CW until hand tight.

SCREWFEEDER CAP


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E. Load the valve spools in the feeder as shown in fi gure 24.

The feeder holds both 3-way and 4-way valve spools, but this skill uses only 3-way.

Figure 24. Valve Spool Feeder

F. Insert the knob/spring assemblies into their feeder, knob side down, as shown in fi gure 25.

Figure 25. Knob/Spring Assembly Feeder

VALVE SPOOL FEEDER

KNOB/SPRINGASSEMBLY FEEDER


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14. Press the Output Power pushbutton to enable the PLC’s outputs. 15. Perform the following substeps to home the station and set manual mode.

A. Verify the lever on the lockout valve is shifted supplying the station with air.

B. Turn the Mode Selector switch to Reset.

This will home all of the actuators. The Start pushbutton should be off when all of the actuators are in the home position.

C. Turn the Mode Selector switch back to Manual. 16. Perform the following substeps to start up the robot.

A. Turn on the power to the robot controller

B. Turn on the PC connected to the robot controller and start the Robot Control software.

C. Open the Mechatronics robot program.

This is mech.prg for the Pegasus and Saturn.prg for the Saturn.

D. Enable the robot drives.

E. Jog the robot to the quick home position.

F. Home the robot. 17. Step the robot through its points to verify they are properly adjusted. Figure 26 describes each point location. Figure 27 shows the critical pick-up

and placement locations. The approach points should be in a straight line away from the critical points. Note that fi gure 27 shows more points than what you need for this skill. This is a listing of all of the points used in the robot program, some of which are only used when the stations are connected together. For example, you will not use points 2 or 3 in this skill. These points are applicable to either the Pegasus or Saturn.

CAUTION

Some of the robot points require that the gripper be closed prior to moving into that position to prevent damage to the hardware. Assess each placement or grip point before moving the robot to that point and close the gripper if necessary.

The Saturn, being a larger robot, has less room to maneuver on the assembly station. Make certain the robot speed is very slow when verifying the points.


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POINT DESCRIPTION

Point 1 Wait Position

Point 2 Approach Aluminum

Point 3 Grip Aluminum

Point 4 Approach Acrylic

Point 5 Grip Acrylic

Point 6 Approach Insertion Position

Point 7 Place at Insertion Position

Point 8 Approach Offl oad Position

Point 9 Grip at Offl oad Position

Point 10 Approach Torque or Bin Position

Point 11 Place at Torque or Bin Position

Point 12 Approach Knob Feeder

Point 13 Grip Knob at Feeder

Point 14 Pluck Knob from Feeder

Point 15 Intermediate Knob Placement Position

Point 16 Approach Knob Placement Position

Point 17 Place Knob in Position

Figure 26. Robot Program Points


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Figure 27. Robot Critical Point Locations

POINT 17POINT 9

POINT 7

POINT 11

POINT 13

POINT 14(KNOB IS CLEAR

OF FEEDER)

SCREW THREAD ENGAGEMENT MODULE(LAST PROCESS)

SPOOL INSERTION MODULE(FIRST PROCESS)

PARTS BIN KNOB FEEDER


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18. Place an acrylic block on the feed stand in the position toward the front of the station.

19. Teach the pickup points for the acrylic part as shown in fi gure 28.

Figure 28. Pick Up Points

•The function of each pickup point is described as follows:

•Point 4 is an approach point above the acrylic valve body

•Point 5 is a grip point for grasping the acrylic valve body This point must be taught with the valve body placed in the robot gripper. 20. Perform the following substeps to run the robot program using the teach

pendant or proceed to Step 21 to run the program using the Robot Control software.

A. From the Main Menu, press [F4] RUN to enter the Run menu.

B. Press [F1] STR.

The teach pendant display will list the default fi le, Controller 1.

C. Press the [NEXT] key.

The program mech will appear in the teach pendant display.

D. Press [ENTER] to run the program.

The robot will retrieve a knob/spring assembly from the feeder and place it in the assembly fi xture, and then move to a wait position.

21. Click on the Run button shown in the File Control toolbar.

POINT 4

POINT 5

VALVEBODY

FEEDSTAND


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22. Perform the following substeps to move the station through its sequence of operations in the manual mode.

1. Robot Places Knob/Spring Assembly at the Screw Thread Engagement Module

2. Robot Places Valve Body at the Spool/Screw Insertion Module

3. Extend Clamp 1

4. Extend Spool Insertion Cylinder

5. Screw Feeder Queue On/Start First Time Delay for Screw Release

6. Retract Spool Insertion Cylinder/Screw Feeder Queue Off/Start Second Time Delay for Completion of Screw Insertion

7. Retract Clamp 1

8. Extend Transport Cylinder

9. Retract Transport Cylinder

10. Extend Clamp 2

11. Extend Knob Cylinder/Start Bolt Motor

12. Knob Extended/Start Dwell Time Delay

13. Dwell Timer Times Out/Retract Knob Cylinder/Turn Motor Off

14. Retract Clamp 2

15. Assembly Complete/Robot Pick Up Assembly and Place in Bin

16. Cycle Ends


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In the manual mode, each momentary press of the start pushbutton causes the station’s next sequence step to be performed. Observe the system and notify your instructor of anything that does not function properly or needs adjustment.

A. Manually place a good acrylic valve body on the feed stand as shown in fi gure 29.

Figure 29. Acrylic Valve Body on the Feed Stand

B. Press the Start pushbutton momentarily to activate Steps 1 and 2 of the sequence.

After receiving the input signal from the Start pushbutton, the robot will pick up a knob/spring assembly and place it on the assembly fi xture and then move back to a wait position. The robot will then move to the acrylic part, pick it up, and place it in the spool insertion module.

C. Press the Start pushbutton momentarily to activate Step 3 of the sequence.

Pushing the Start pushbutton will cause the PLC to activate SOL2 and extend clamp cylinder 1 to hold the valve in place.

D. Press the Start pushbutton momentarily to activate Step 4 of the sequence.

The PLC will energize SOL1 to extend the spool insertion cylinder, which pushes the spool into the valve body.

E. Press the Start pushbutton momentarily to activate Step 5 of the sequence.

The PLC energizes SOL4, which activates the screw insertion module queue. The queue releases a screw and it feeds part way into the spool, but keeps it from going completely into the spool, as it would hit the spool insertion cylinder.


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F. Press the Start pushbutton momentarily to activate Step 6 of the sequence.

The PLC de-energizes SOL1 and the spool insertion cylinder is retracted. Once the retract limit switch is made, SOL4 is turned off allowing the screw insertion queue to release the screw. The next screw in line is actu-ally pushing the screw into the spool. The queue cylinder prevents the next screw from extending into the assembly area.

G. Press the Start pushbutton momentarily to activate Step 7 of the sequence.

The PLC de-energizes SOL2 and clamp cylinder 1 retracts.

H. Press the Start pushbutton momentarily to activate Step 8 of the sequence.

SOL5 is energized and the transport cylinder extends, pushing the partial assembly on to the knob/spring assembly module.

I. Press the Start pushbutton momentarily to activate Step 9 of the sequence.

SOL5 is de-energized and the transport cylinder retracts.

J. Press the Start pushbutton momentarily to activate Step 10 of the sequence.

The PLC energizes SOL3, which causes clamp cylinder 2 extends to hold the valve body in place during the knob/spring assembly process.

K. Press the Start pushbutton momentarily to activate Steps 11 and 12 of the sequence.

SOL6 is energized and the knob assembly cylinder extends. The screw motor also turns on. The cylinder pushes the knob/spring assembly into the spool while the rotating motor shaft engages the screw head, turning it to thread screw into the knob. The motor will turn until the knob cylinder reaches the extend switch. This indicates that the knob threads have engaged on the screw.

L. Press the Start pushbutton momentarily to activate Step 13 of the sequence.

The PLC de-energizes SOL6 and the knob assembly cylinder retracts. The screw motor also turns off.

M. Press the Start pushbutton momentarily to activate Step 14 of the sequence.

Clamp cylinder 3 retracts indicating the end of the assembly process.


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N. Press the Start pushbutton momentarily to activate Step 15 of the sequence.

The PLC signals the robot that the valve is assembled. The robot then moves over to the assembly, picks it up, and drops it in the part bin. The robot will then get a new spring/knob assembly, place it in the assembly station, and move to a wait position.

23. Turn the Mode Selector switch to Auto. If you successfully single-stepped through the complete sequence and all

of the actuators are back in their home position, the Start pushbutton lamp should be off at this time and you can move on to Step 25. If it is not, perform Step 24 to reset the actuators.

24. Perform the following substeps to home the station and set automatic mode.

A. Remove the spring/knob assembly from the assembly station and place it back in the feeder, knob end down.

B. Turn the Mode Selector switch to Reset.

This will move all of the actuators back to their home positions. The robot will then get a new spring/knob assembly, place it in the assembly station, and move to a wait position.

C. Turn the Mode Selector switch to Auto. 25. Manually place a good valve body in the recess provided on the Feed Stand. 26. Press the Start pushbutton to start the automatic cycle. Observe the station while it goes through one cycle. It is programmed to run

through one cycle and then stop. The Start pushbutton indicator is on solid during the whole cycle to indicate the station is operating.

27. Perform the following substeps to test the operation of the station.

A. Manually place a good acrylic valve body in the recess provided on the Feed Stand.

B. Press the Start pushbutton to start the automatic cycle.

C. During the middle of the cycle, press the Stop pushbutton to stop the system.

The Stop pushbutton is programmed as a halt function, which means the station will complete its current sequence step and stop with all power remaining on.

You should see the operation continue to the end of the current sequence step.


31

D. Observe the operator panel indicators and record their status in the table below.

OPERATOR PANEL INDICATORS

Indicator Status (On/Off/Blinking)

Output Power Lamp

Start Lamp

Emergency Stop Lamp

Figure 30. Operator Panel Indicators

Since this is a halt, the machine can resume operation, so you should observe that Output power remains on and the start pushbutton should be off. It has been programmed to do so when the station is in the auto mode and ready to run its automatic cycle. The emergency stop lamp should be off because it is not pressed.

E. Observe the PLC processor’s status indicators and record their status.

PLC PROCESSOR STATUS INDICATORS

Indicator Status (On/Off)

SF

DC5V

FRCE

RUN

STOP

Figure 31. PLC Processor Status Indicators

You should see that the PLC processor’s DC5V and Run indicator lights are on, because the station is halted and ready to resume automatic operation.

F. Observe the PLC I/O modules’ status indicators to see if any are on.

You should see various input and output indicators on. Which ones depend on the point in the operation at which the Stop pushbutton was pushed.

G. Press the Start pushbutton to restart the system.

It should continue where it left off and fi nish the cycle.

NOTE

If any actuators are manually moved while the system is halted, the station may not resume operation when the start pushbutton is pressed. If this occurs, go to Step 29 and restart the system.


32

28. Repeat Step 26 three times, stopping the cycle with the Stop pushbutton at different times to observe how it reacts.

29. Perform the following substeps to restart the station IF any of the inputs changed after the Stop pushbutton is pressed.

If any of the inputs were changed, like a part removed from the conveyor, or a cylinder moved physically, the system cannot be restarted with the Start pushbutton. This is because the input signals will no longer match those needed to begin the sequence. This is a protective measure to prevent damage to the system.

A. Turn the Mode Selector switch to Reset.

This will move all of the actuators back to their home positions.

Once the actuators are reset, the Start pushbutton lamp should turn off.

B. Manually place a good valve body in the recess provided on the Feed Stand.

C. Turn the Mode Selector switch back to Auto.

D. Press and release the Start pushbutton to start the automatic cycle.

Observe the system while it goes through a cycle before continuing to the next step.

30. Perform the following substeps to record the operation of the station when the Emergency Stop pushbutton is pressed.

This step will show you how the system is programmed to respond to the emergency stop pushbutton.

A. Manually place a good valve body in the recess provided on the Feed Stand.

B. Press and release the Start pushbutton.

C. During the cycle, press the Emergency Stop pushbutton.

Observe the operator panel indicators and record their status in the table below.



Output Power Lamp

Start Lamp

Emergency Stop Lamp


Since this is an emergency stop, the machine cannot resume operations. You should observe that the output power is off, the Start pushbutton lamp is off, and the Emergency Stop lamp is on. You should also note that the robot stopped immediately after the e-stop was pressed, although it does not lose power. The robot’s program is designed to end immediately when the emergency stop is pressed. The Emergency Stop function does not remove the air supply.


33

D. Observe the PLC processor’s status indicators and record their status.



SF

DC5V

FRCE

RUN

STOP


You should see the PLC processor’s DC5V and Run indicator lights on.

E. Observe the PLC I/O modules’ status indicators to see if any are on.

You should see various input indicators on, but all output indicators are off. This is because the Emergency stop circuit breaks power to the Output power contactor, which drops all output power.

31. Perform the following substeps to recover from the Emergency Stop.

A. Remove any valve bodies or spring/knob assemblies that are on the station.

B. Pull the Emergency Stop pushbutton out.

C. Press the Output Power pushbutton to turn the outputs back on.

You should hear the contactor pull in to re-establish the power to the outputs. You should also see the robot move to the spring/knob assembly feeder, pick an assembly from the feeder, and place it in the assembly fi xture.

Reset is not necessary at this point as all of the valves are spring return and will go back to their home position when they no longer have an output holding them.

D. Place a good valve body into the recess on the Feed Stand.

E. Turn the Mode Selector switch back to Auto.

F. Press and release the Start pushbutton to start the automatic cycle.

Observe the system while it goes through a cycle.

G. Press the Stop pushbutton after the cycle completes.

H. Manually place a good valve body in the recess provided on the Feed Stand after the cycle completes.

32. Perform the following substeps to record the operation of the station when it experiences a power loss.

This will show you how the station is programmed to respond to a power loss.

A. Press the Start pushbutton to start an automatic cycle.

B. During the middle of the cycle turn the Main Power switch to Off to remove power to the system.


34

C. Observe the operator panel indicators and record their status in the table below.



Output Power Lamp

Start Lamp

Emergency Stop Lamp


Because this is a power loss, simulated by turning the Main Power switch off, power to everything past the Main Power switch is turned off. You should see all operator panel indicator lamps and PLC indicators are off, but you will notice that the pneumatic power remains. You should also have noted that all of the cylinders return to their home position as there is no output power to keep the single-acting solenoids energized. You should also note that the robot stopped immediately after the Main Power switch was turned off, although it does not lose power. The robot’s program is designed to end immediately when the station power is dropped.

D. Observe the PLC processor’s status indicators and record which indica-tors are on.



SF

DC5V

FRCE

RUN

STOP


You should see all indicators off because there is no power to the PLC.

E. Observe the PLC I/O modules’ status indicators to see if any are on.

Again, you should see all input and output indicators off because the modules have no power.


35

33. Perform the following substeps to recover from the power loss.

A. Remove any valve bodies that are on the work surface.

B. Place the Mode Selector switch in the Manual position.

C. Turn the station’s Main Power switch to the On position.

D. Press the Output Power pushbutton to enable the PLC’s outputs

You should also hear the contactor located next to the PLC module pull in. The Start pushbutton lamp should be off because the station is ready for operation

E. Turn the Mode Selector switch to Auto.

F. Manually place a good valve body in the recess provided on the Feed Stand.

G. Press the Start pushbutton to restart the operation.

You should see the system start through its sequences.

H. Run the system through two complete cycles to make sure it has recovered correctly.

34. Perform the following substeps to shutdown the robot controller and Robot Control software.

A. Move the robot to the home position.

B. Disable the Robot’s drives.

C. Close the Robot’s Control software.

D. Turn off the robot controller. 35. Perform the following substeps to power down the station.

A. Turn the Main Power switch Off.

B. Close the SIMATIC Manager.

C. Turn off the PC and monitor.

D. Perform a lockout/tagout on the system’s electrical power source.

E. Perform a lockout/tagout on the system’s pneumatic power source.


36

SEGMENT 1 SELF REVIEW

1. Robots in assembly systems are used for assembly or for _________

2. In robotic assembly systems, the robots are often interfaced to _____ to enable them to coordinate operations.

3. Servo robotic assembly systems use assembly _________, parts feeders, and a robot.

4. Pick and place assembly systems are typically controlled by a _____.

5. Pick and place assembly systems use __________ that lift, move, and place objects in desired locations.

6. Gravity feeders hold _______ for use in the process.

7. Automatic screw feeder cylinders are regulated using __________.


37

SEGMENT 2COMPONENT ADJUSTMENT

OBJECTIVE 5 DESCRIBE HOW TO ADJUST A PARTS FEEDER WITH ESCAPEMENT

Some feeder escapements must be adjusted mechanically. One example is the parts chute escapement shown in fi gure 36. In this example, the escapement is a spring loaded ball, which holds the parts in the chute until an external force is applied to pull a part past the escapement. The spring force must be adjusted so that it holds the parts back but is not so high that a part cannot be pulled out of the chute.

In many applications, a sensor is positioned to read when the feeder is out of parts, sending a signal to the PLC to stop the sequence until more parts are put in the chute. This sensor may also require physical adjustment so that it senses a part when present and it doesn’t sense parts when the feeder is out.

Figure 36. Mechanical Adjustments on a Parts Feeder

PARTFEEDER

PART

ESCAPEMENT

PARTPRESENTSENSOR


38

The availability of the part relies on the adjustment of the feeder to allow the part to feed properly. The part should move smoothly and quickly into place. If it does not, the feeder may require mechanical adjustments. This may include adjusting the size of the feeder, modifying the angle at which it is oriented, or some other physical adjustment.

Part feeders often position the part for a part placement device, which makes the positioning of the part feeder critical. Mounting holes may be slotted or the bases may be adjustable using adjustment screws, both of which provide a method of properly aligning the feeder with the mating part or pickup device location.

Parts Feeder with Escapement Adjustment

To adjust a feeder, fi rst test the part chute to verify that the parts drop smoothly and evenly. This may require manually actuating cylinders or manually removing parts from the part present location, if applicable. Make any adjustments to enable the parts to drop easily using the adjustment screw. Also verify that the part can be picked up from its current position. This also may require manually actuating cylinders or pickup devices. Make any necessary location adjustments using the chutes adjustment screws or mounting screws.

For example, to adjust the friction ball escapement in fi gure 37, the retaining nut is loosened slightly. The escapement screw is then adjusted. Moving the fric-tion ball in towards the part increases the friction, which increases the amount of force required to remove the part. Moving the friction ball out away from the part decreases the friction, which decreases the amount of force required to remove the part. Once the escapement is set to the desired position, the retaining nut is tight-ened preventing the escapement from moving.

Figure 37. Adjust Part Chute

MOUNTINGSCREWS

ESCAPEMENTADJUSTMENT

SCREW

MOUNTINGBRACKETS ESCAPEMENT


39

SKILL 2 ADJUST A PARTS FEEDER WITH ESCAPEMENT

Procedure Overview

In this procedure, you will adjust and test the parts feeder with escapement on the 87-MS5 Servo Robotic Assembly station.

1. Locate the 87-MS5 Servo Robotic Assembly station. 2. Verify that this station has been separated from any other stations. If it has

not, then separate it from the other stations. If it has, then proceed to Step 3. 3. Perform the following safety check before you begin working on the station.

Make sure that you can answer yes to each item before proceeding.





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40

4. Locate the knob/spring assembly gravity feeder, shown in fi gure 39.

Figure 39. Knob/Spring Assembly Feeder

5. Perform the following substeps to adjust the escapement on the part feeder.

A. Remove all of the knob/spring assemblies from the feeder.

B. Locate the escapement/stop and its adjustment screw, shown in fi gure 40.

Figure 40. Escapement and Adjustment Screw

ADJUSTMENTSCREW NUT

ESCAPEMENT


41

C. Loosen the nut on the adjustment screw by turning it 2 turns CCW.

This should be just fi nger tight, but if a wrench is required, use a 3/8 in. open-end wrench to loosen it. You can obtain this from your instructor.

D. Back the adjustment screw out 1 turn by turning it CCW.

This will remove the escapement so that it will no longer stop parts from falling out.

E. Place a knob/spring assembly, knob side down, into the top of the part feeder and let go.

The knob/spring assembly should fall straight through the feeder.

F. Tighten the escapement adjustment screw 1 turn CW.

G. Drop another knob/spring assembly into the feeder.

This time, the escapement should stop the part from falling out of the feeder.

H. Tighten the nut on the adjustment screw by turning it CW 2 turns.

I. Replace the knob/spring assemblies in the feeder. 6. Perform the following substeps to adjust the location of the part feeder on its

support post.

A. Obtain from your instructor a 4 mm hex wrench.

B. Use a pencil to mark the position of the knob/spring feeder support bracket, as shown in fi gure 41.

Figure 41. Feeder Support Bracket Location

MARKLOCATION


42

C. Using the hex wrench, loosen the two bolts on the bracket, shown in fi gure 38, 1 turn each.

This should make the bracket loose enough to move without unthreading the bolts from their T-nuts.

D. Move the bracket up and down in the slotted extrusion and note how easily the location can be modifi ed.

Keep in mind that if this location is modifi ed, at least 4 robot teach points would have to be taught over again.

E. Move the bracket back to the location you previously marked.

F. Tighten the nuts with the hex wrench.

G. Return the wrench(es) to your instructor.


43

OBJECTIVE 6 DESCRIBE HOW TO ADJUST AN AUTOMATIC SCREW FEEDER

Automatic screw feeders, such as the one shown in fi gure 42, use fl ow control valves to control the speed at which the screw is released into the process. Adjust-ments are made to either accelerate or decelerate the speed of the cylinders and thus the release of the screw.

Figure 42. Automatic Screw Feeder

The following procedures are recommended for adjusting this type of auto-matic screw feeder.

CYLINDERS

INDUCTIVE PARTPRESENT SENSOR

REMOVABLE CAPTO ADD SCREWS TO

QUEUE

SCREW INSERTION

MODULE

SCREWPATH

TUBING HOLDSSCREWS IN

QUEUEAIR

REGULATOR

DIALINDICATOR


44

Step 1: Adjust the fl ow controls for the screw stop cylinder (works inde-pendently) - By adjusting the fl ow controls on this cylinder, the speed at which the screw is fed into the system and the next screw is trapped are modifi ed. Turning the adjustment CW reduces the speed by restricting the air fl ow, while turning it CCW increases the fl ow and the speed at which the cylinder retracts. When making adjustments to the fl ow control, make sure the cylinder retracts and extends at a speed that allows the part to be trapped and released at the correct times while not slowing the production process.

Figure 43. Flow Control on Independent Cylinder

CYLINDER 3

FLOWCONTROL

VALVE


45

Step 2: Adjust the fl ow controls for the cylinders working together - These cylinders trap the head of the screw being inserted until the process is ready for it. Turning the adjustment CW reduces the speed by restricting the exhaust air fl ow, while turning it CCW increases the fl ow and so the speed at which the cylinder retracts. This will change the speed the screw is released from the screw guide.

Figure 44. Flow Controls on Cylinder Pair

SCREWGUIDES

SCREW

FLOW CONTROLVALVE

FLOWCONTROL

VALVE

CYLINDER 1

CYLINDER 2


46

SKILL 3 ADJUST AN AUTOMATIC SCREW FEEDER

Procedure Overview

In this procedure, you will adjust and test an automatic screw feeder. This will familiarize you with the operation and adjustment of an automatic screw feeder system.








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4. Verify that the Feed Stand is installed on the station. If it is not, install it. The feed stand is used when the 87-MS5 is separated from the other station

to enable the robot to pick up the valve bodies. 5. Verify the parts bin is installed on the station. If it is not, install it. The parts bin is used when the station is separated from the other stations to

catch the parts as the robot drops them. 6. Connect an air supply to the station’s air manifold quick connect. 7. Perform the following substeps to power up the 87-MS5 Servo Robotic

Assembly station.

A. Remove the lockout/tagout device from the pneumatic power source.


47

B. Turn on air to the station by shifting the lever on the pneumatic lockout valve.

C. Set the station’s air supply regulator to 50 psi/345 kPa.

D. Set the screw feeder’s air supply regulator to 12 psi/82.7 kPa. 8. Perform the following substeps to adjust the extend and retract fl ow controls

on the screw feeder cylinders.

Figure 46. Screw Feeder Cylinders

A. Use the cylinder’s manual override to extend and retract the cylinders and notice how quickly it does each movement.

Extend ___________________________________________ (slow/fast)

Retract ___________________________________________ (slow/fast)

B. Rotate the extend fl ow control valve three turns CW.

C. Rotate the retract fl ow control valve three turns CCW.

D. Use the cylinder’s manual override to extend and retract the cylinder and note how each movement was affected by the adjustment.

Extend ____________________________________________________

Retract ____________________________________________________

You should have seen the valve extend more slowly and retract more quickly.

E. Rotate the extend fl ow control three turns CCW to position it to the orig-inal setting.

FLOW CONTROL VALVE

CYLINDER 3

FLOW CONTROL VALVE

CYLINDER 1

CYLINDER 3


48

F. Rotate the retract fl ow control three turns CW to position it to the original setting.

G. Use the cylinder’s manual override to verify that the cylinder’s settings are back to their original positions.

9. Perform a lockout/tagout on the system’s pneumatic power source.

OBJECTIVE 7 DESCRIBE HOW TO ADJUST A PNEUMATIC PART SHUTTLE

A pneumatic part shuttle, such as the one shown in fi gure 47, uses a rodless cylinder with an attached arm or tab to shuttle the parts from one location to the next. In the example shown in fi gure 48, the arm is bolted to the carriage. This arm will extend through a slot in the work surface above it to slide the part from one process to the next. The cylinder also has two meter in fl ow control valves that are used to adjust the speed of the cylinder in either direction.

Figure 47. Rodless Cylinder

MOUNTINGBLOCK

FLOWCONTROL

RODLESSCYLINDER

SHUTTLEARM

CARRIAGE FLOWCONTROL

MOUNTINGBLOCK


49

Figure 48. Part Shuttle Application

Adjusting a part shuttle such as the one in the example involves adjusting the fl ow control valves on the cylinder. Turning the fl ow control CCW will decrease the speed, while turning it CW will increase the speed. If the fl ow control adjust-ment includes a locking nut to prevent vibration from changing the setting, make sure the nut is loosened before changing the setting and tighten it after the new setting is made.

FLOW CONTROLFOR EXTEND

FINAL PARTLOCATION ATPROCESS 2

SHUTTLEARM ON

CARRIAGE

ORIGINAL PARTLOCATION ATPROCESS 1

FLOW CONTROLFOR RETRACT

SHUTTLE ARM EXTENDSTHROUGH WORK SURFACE


50

SKILL 4 ADJUST A PNEUMATIC PART SHUTTLE

Procedure Overview

In this procedure, you will adjust and test a pneumatic part shuttle. This will familiarize you with the operation and adjustment of a pneumatic part shuttle system.








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4. Connect an air supply to the station’s air manifold quick connect. 5. Perform the following substeps to power up the 87-MS5 Servo Robotic

Assembly station.

A. Remove the lockout/tagout device from the pneumatic power source.

B. Turn on air to the station by shifting the lever on the pneumatic lockout valve.

C. Set the station’s air supply regulator to 50 psi/345 kPa.

D. Set the screw feeder’s air supply regulator to 12 psi/82.7 kPa.


51

6. Perform the following substeps to adjust the extend and retract fl ow controls on the pneumatic part shuttle cylinder.

Figure 50. Part Shuttle Cylinder

A. Use the cylinder’s manual override to extend and retract the cylinders and notice how quickly it does each movement.

Extend ___________________________________________ (slow/fast)

Retract ___________________________________________ (slow/fast)

B. Rotate the extend fl ow control valve three turns CCW.

C. Rotate the retract fl ow control valve three turns CW.

D. Use the cylinder’s manual override to extend and retract the cylinder and note how each movement was affected by the adjustment.

Extend ____________________________________________________

Retract ____________________________________________________

You should have seen the valve extend more slowly and retract more quickly.

E. Rotate the extend fl ow control three turns CW to position it to the original setting.

F. Rotate the retract fl ow control three turns CCW to position it to the orig-inal setting.

G. Use the cylinder’s manual override to verify that the cylinder’s settings are back to their original positions.

7. Perform a lockout/tagout on the system’s pneumatic power source.

FLOW CONTROL

PARTSHUTTLECYLINDER


52


1. A parts feeder with an escapement usually includes a _____ to indicate when there are no parts left.

2. If the part does not feed properly ______ adjustments to the feeder may be required.

3. A part chute should be adjusted to allow the parts to drop _____.

4. Pneumatic cylinders have _____ to control the speed they extend and retract.

5. By regulating the speed at which the _________ extend and retract, the speed at which the part is released and fed into the part can be controlled.

6. A rodless cylinder used as a part shuttle uses _________ to control extend and retract speed.


53

SEGMENT 3MODULE SEQUENCING

OBJECTIVE 8 DESCRIBE A SEQUENCE OF OPERATION OF A PART INSERTION MODULE

A typical part insertion module uses pick and place components to assemble parts by placing one part into another part. One example is shown in fi gure 51, which shows a module that inserts a spool into a valve body. This example uses a double-acting cylinder to push a spool from a feeder into the valve body. The cylinder has magnetic reed switches mounted to it that indicate to the PLC when it has completed its stroke.

The part insertion module also includes a clamping cylinder to hold the part stationary while work is being performed on it. The spool feeder portion of the module is equipped with an inductive sensor to detect when parts are present.

Figure 51. Part Insertion Module Construction

VALVESPOOLS

PART PRESENTSENSOR

(INDUCTIVE)

CLAMPINGCYLINDER

SINGLESOLENOID

DCV(SOL2)

MR1

DOUBLE-ACTINGCYLINDER

SINGLESOLENOID

DCV(SOL1)

MAGNETIC REEDSWITCHES

MR2

MR3

VALVE BODY

FEEDER

FIXTURE


54

The part insertion module is generally controlled by a PLC, but could also be controlled by robotic I/O. In either case, the sequence will be similar to that shown in the following table.

PART INSERTION MODULE SEQUENCE

STEP INPUT OUTPUT

1 Receive Start input (S1 on) Extend Clamp 1 (SOL2 on)

2 Clamp 1 Extended (MR3 on) Extend Part Insertion Cylinder (SOL1 on)

3 Part Insertion Cylinder Extended (MR1 on)

Retract Part Insertion Cylinder

4 Part Insertion Cylinder Retracted (MR2 on)

Retract Clamp 1

5 Clamp 1 Retracted Cycle Ends

Figure 52. Part Insertion Module Sequence of Operation


55

Initial Condition

The part insertion module must be in some pre-determined state before any sequence may take place. Many times this will be a state in which both the clamp 1 cylinder and the insertion cylinder are retracted (MR2 actuated). Typically, there is an interlock, indicating that motion at the source and/or destination station has stopped and it is now safe to transfer. One example would be that the source station’s transfer table has stopped moving. If these initial conditions are not satis-fi ed, the part insertion module will not operate and the PLC controlling the module may even provide an alarm light or message to the operator, indicating that oper-ator intervention is necessary.

Figure 53. Initial Condition

SOL2

CLAMP #1 CYLINDER

FROMSOURCE

CYLINDEREXTENDED

MR3

SOL1

PART INSERTION CYLINDER

CYLINDERRETRACTED

MR2

CYLINDEREXTENDED

MR1

MR2 ON INSERTIONCYLINDER

RETRACTED

PARTINSERTIONCYLINDER

CLAMP 1CYLINDER

RETRACTED


56

Step 1: Receive Start Input, Extend Clamp 1 Cylinder

In this step, the PLC controlling the part insertion module receives an input to start the sequence. The input may be from another workstation, an operator, or the robot tending the module. After receiving the input signal, the PLC energizes SOL2 to extend Clamp 1 cylinder and clamp the part in place. This holds the part steady while assembly operations are being performed.

Figure 54. Step 1: Receive Start Input, Extend Clamp 1 Cylinder

SOL2CLAMP #1 CYLINDER

FROMSOURCE

CYLINDEREXTENDED

MR3

SOL1


CYLINDERRETRACTED

MR2

CYLINDEREXTENDED

MR1

CLAMP 1BEGINS TO

EXTEND


57

Step 2: Clamp 1 Cylinder Extended, Extend Part Insertion Cylinder

Once the clamp cylinder’s magnetic reed switch (MR3) indicates that the cylinder is extended, the PLC energizes SOL1 to extend the part insertion cylinder. This will push the part from the part feeder and into the waiting assembly.

Figure 55. Step 2: Clamp 1 Cylinder Extended, Extend Part Insertion Cylinder


FROMSOURCE

CYLINDEREXTENDED

MR3

SOL1PART INSERTION CYLINDER

CYLINDERRETRACTED

MR2

CYLINDEREXTENDED

MR1

MR3ONPART INSERTION

CYLINDER BEGINS

TO EXTEND

CLAMP 1EXTENDED


58

Step 3: Part Insertion Cylinder Extended, Retract Part Insertion Cylinder

The extension of the part insertion cylinder is indicated by its magnetic reed switch (MR1), which causes the PLC to de-energize SOL1. This will allow the part insertion cylinder to retract.

Figure 56. Step 3: Part Insertion Cylinder Extended, Retract Part Insertion Cylinder


FROMSOURCE

CYLINDEREXTENDED

MR3

SOL1


CYLINDERRETRACTED

MR2

CYLINDEREXTENDED

MR1

PARTIN

ASSEMBLYPART INSERTION

CYLINDER EXTENDED

MR2OFF

MR1ON


59

Step 4: Part Insertion Cylinder Retracted, Retract Clamp 1 Cylinder

When the part insertion cylinder is retracted, it turns on switch MR2. This causes SOL2 to turn off and retract the clamp 1 cylinder. A time delay is started to give the cylinder time to retract.

Figure 57. Step 4: Part Insertion Cylinder Retracted, Retract Clamp 1 Cylinder

SOL2

CLAMP #1 CYLINDER

FROMSOURCE

CYLINDEREXTENDED

MR3

SOL1


CYLINDERRETRACTED

MR2

CYLINDEREXTENDED

MR1

CYLINDERRETRACTED

MR1OFF

MR2ON


60

Step 5: Clamp 1 Retracted, Cycle Ends

Once the time delay ends, the clamp 1 cylinder is retracted. This loosens the part and allows it to be removed for further processing. The cycle then stops until it receives the start input again.

Figure 58. Step 5: Clamp 1 Retracted, Cycle Ends

SOL2

CLAMP #1 CYLINDER

FROMSOURCE

CYLINDEREXTENDED

MR3

SOL1


CYLINDERRETRACTED

MR2

CYLINDEREXTENDED

MR1

CLAMPRETRACTED


61

The sequence just described is summarized by the sequence diagram in fi gure 59.

PART INSERTION MODULE SEQUENCE OF OPERATIONS

Step Input Action Output Action

INPUTS OUTPUTS

0 Start Condition 0 1 0 1 0 0 0

1 Receive Start Input Extend Clamp Cylinder 1 1/0 1

2 Clamp 1 Cylinder Extended Extend Part Insertion Cylinder 1 1

3 Part Insertion Cylinder Extended Retract Part Insertion Cylinder 1 0 0

4 Part Insertion Cylinder Retracted Retract Clamp 1 0 1 0

5 Clamp 1 Cylinder Retracted Cycle Ends 0

End Condition 0 1 0 1 0 0 0

Figure 59. Sequence Diagram

Sta

rt P

B

Sto

p P

B

MR

1

MR

2

MR

3

SO

L1

SO

L2


62

SKILL 5 DESIGN A PLC PROGRAM THAT SEQUENCES A PART INSERTION MODULE

Procedure Overview

In this procedure, design a PLC project to control a part insertion module given the following information.

1. Design a PLC project to control a part insertion module given the following information.

The general sequence, I/O diagram, power diagrams as follows: General Sequence

1) Pressing the Start pushbutton causes the Clamp 1 cylinder to extend.

2) After the Clamp 1 cylinder is extended, indicated by MR3, the spool inser-tion cylinder is extended

3) After the spool insertion cylinder is extended (MR1 on), it is retracted.

4) After the spool insertion cylinder is retracted (MR2 on), the clamp cylinder is retracted.

5) After the clamp cylinder is retracted (1 second time delay), then the cycle ends.

Special Conditions• The start pushbutton lamp will be off when the station is in its home posi-tion and on solid when it is running.• The transport cylinder (SOL5), clamp 1 cylinder (SOL2), and the spool insertion module (SOL1) should be manually positioned at the home posi-tion using the manual overrides.• A valve body should be manually placed in the recess on the work surface.


63

• Pressing the Stop pushbutton at any time should cause the sequence to stop (or halt) at the end of its current step. Pressing the Start pushbutton should resume the sequence.• The cycle should repeat when a new part is placed onto the work surface and the Start pushbutton is pressed.

Figure 60. I/O Diagram

Figure 61. Power Diagram

I/O DIAGRAM

I0.0

Q4.5

Q4.6

START INPUT SPOOL INSERTIONEXTEND (SOL1)

CLAMP 1EXTEND (SOL2)

PB

I1.2

MR1SPOOL INSERTION

EXTENDED

OUTPUTSINPUTS

I1.3

MR2SPOOL INSERTION

RETRACTED

I1.4

MR3CLAMP 1

EXTENDED

SOL2

CLAMP 1 CYLINDER

FROMSOURCE

CYLINDEREXTENDED

MR3

SOL1

SPOOL INSERTION CYLINDER

CYLINDERRETRACTED

MR2

CYLINDEREXTENDED

MR1


64

PART INSERTION MODULE SEQUENCE OF OPERATIONS


INPUTS OUTPUTS

0 Start Condition 0 1 0 1 0 0 0


2 Clamp 1 Cylinder Extended Extend Part Insertion Cylinder 1 1

3 Part Insertion Cylinder Extended Retract Part Insertion Cylinder 1 0 0

4 Part Insertion Cylinder Retracted Retract Clamp 1 0 1 0

5 Clamp 1 Cylinder Retracted Cycle Ends 0

End Condition 0 1 0 1 0 0 0


2. Perform the following substeps to open the PLC programming software.



C. Start the SIMATIC Manager. 3. Perform the following substeps to create a project.

A. Create a Project named L7S4XXX where XXX represents your initials.

B. Create an S7 Station object for the station and confi gure its hardware.

C. Open Organizational Block OB1.

D. Enter the program that you developed in Step 1 into Organizational Block OB1.

E. Save OB1. 4. Locate the 87-MS5 Servo Robotic Assembly station. 5. If the 87-MS5 Servo Robotic Assembly station is connected to another 87-

MS station, separate the stations. If the 87-MS5 Servo Robotic Assembly station is already disconnected, continue to Step 6.

Sta

rt P

B (

I0.0

)

Sto

p P

B (

I0.1

)

MR

1 (i1

.2)

MR

2 (i1

.3)

MR

3 (i1

.4)

SO

L1 (

Q4.

5)

SO

L2 (

Q4.

6)


65






Tie up long hair






7. Connect an air supply line to the station’s air manifold quick connect. 8. Plug the station’s power cable into a wall outlet. 9. Perform the following substeps to power up the 87-MS5 Servo Robotic

Assembly station.

A. Place the Mode Selector switch in the Manual position.

B. Remove the lockout/tagout device from the electric power source.


D. Turn on the air to the station by shifting the lever on the lockout valve.


F. Turn the station’s Main Power Switch to the On position. 10. Perform the following substeps to download the project to the PLC.

A. Reset the PLC.

B. Download the SIMATIC 300 Station object to the PLC.


C. Click Yes on the dialog to complete a warm restart. 11. Go online with the processor and monitor the OB1 Block. 12. Press the Output Power pushbutton to enable the PLC’s outputs.


66

13. Perform the following substeps to test the operation of the program.

A. Verify that there are spools inserted into the part feeder.

If there are none, obtain some from your instructor.

B. Place a good valve body in the recess provided in the orientation shown in fi gure 64.

Figure 64. Valve Body Orientation

C. Press and release the Start pushbutton.

The following sequence should occur:• The clamp 1 cylinder should extend.• After the clamp 1 cylinder has extended, the spool insertion cylinder should extend, pushing a spool into the valve body.• After the spool insertion cylinder has extended, it should retract.• After the spool insertion cylinder has retracted, the clamp 1 cylinder should retract.This successfully completes one cycle of the part insertion module.

D. Manually place a good valve body in the recess provided on the work surface.

E. Press and release the Start pushbutton.

The cycle should repeat.

F. Repeat substeps D through F until you are familiar with the operation of the part insertion module.

14. Print out a copy of the ladder logic program and place it in your portfolio. It will be used in your assessment.


67

15. Click the Monitor button to go offl ine from the processor. 16. Use the PLC programming software to place the PLC into Stop mode. 17. Perform the following substeps to shut down the 87-MS5.

A. Close the LAD/STL/FBD Editor.



D. Turn the 87-MS5’s Main Power switch to Off.

E. Perform a lockout/tagout on the system’s electrical power source.

F. Perform a lockout/tagout on the system’s pneumatic power source.


68

OBJECTIVE 9 DESCRIBE A SEQUENCE OF OPERATION OF A SCREW FEED MODULE

An example of a screw feed module is shown in fi gure 65. This example includes a single-solenoid directional control valve and three double-acting cylin-ders that are used to control the screws as they are fed into the part. The module is equipped with an inductive sensor to detect when there are screws present in the queue.

When the PLC receives a request for a screw and the part present sensor is on, the three cylinders start shifting to release the screw. One cylinder, which holds the screw back by restraining the screw head, begins to extend while the other two cylinders open a screw guide that keeps the screw straight and prevents screws from extending into the assembly area.

When the system is ready, one cylinder retracts to let the next screw move into the screw guide which is now closed. The screw behind the one being inserted pushes the screw the rest of the way into the part.

Figure 65. Screw Feed Module Construction

SOL2

SCREWS

SCREWFEED

MODULE

PARTPRESENTSENSOR

(IND3)

SOL4

VALVE/SPOOLASSEMBLY

CLAMPCYLINDER

CLAMPEXTENDED (MR3)

FIXTURE

SINGLE - SOLENOIDDIRECTIONAL CONTROL VALVE


69

A screw feed module’s sequence will be similar to that shown in the following table.

SCREW FEED MODULE SEQUENCE OF EVENTS

STEP INPUT OUTPUT

1 Receive Start input (S1 on) Extend Clamp 1 Cylinder (SOL2 on)

2 Clamp 1 Cylinder Extended/ Screws Present (MR3, IND3 on)

Screw Feed Queue On/Start Time Delay (SOL4 on, Screw Insert Timer 1 Starts)

3 Time Delay Ends/Screw Feed(Timer 1 done)Cylinders Return to Home Position

Screw Feed Queue Off/Second Time Delay Starts (Screw Insert Timer 2 Starts)

4 Second Time Delay Ends/Screw Completely Inserted into Valve Body(Timer 2 done)

Retract Clamp 1 Cylinder


Figure 66. Screw Feed Module Sequence of Operation


70

Initial Condition

The screw feed module must be in some pre-determined state before any sequence may take place. In this example, the clamp cylinder is retracted, part present sensor IND3 is on, and the screw insertion queue cylinders are in their proper positions. If these initial conditions are not satisfi ed, the screw feed module will not operate and an alarm light or message to the operator may be activated.


CYLINDER 2EXTENDED

IND3 ON

CLAMP 1CYLINDER

RETRACTED

CYLINDER 1RETRACTED

CYLINDER 3RETRACTED

SOL4

FROMSOURCE

SOL2

CLAMP 1 CYLINDER

CYLINDEREXTENDED

MR3

SCREW INSERTION QUEUE CYLINDERSSCREW GUIDEQUEUE CYLINDER 1

SCREW GUIDEQUEUE CYLINDER 2

SCREW RESTRAINTQUEUE CYLINDER 3

PNEUMATIC SCREW FEEDER TUBE

SCREW GUIDECYLINDER 2


SCREW RESTRAINTCYLINDER 3

TOP VIEW OF CYLINDERS


71

Step 1: Receive Start Input, Extend Clamp 1 Cylinder

In this step, the PLC controlling the screw feed module receives an input to start the sequence. The input may be from another workstation, an input detecting that a part is present and ready for assembly, or it may be from an operator. After receiving the input signal, the PLC energizes SOL2 and the clamp cylinder extends.

Figure 68. Step 1: Input Signal Received, Extend Clamp 1 Cylinder

CLAMP 1BEGINS TO

EXTEND

SOL4

FROMSOURCE

SOL2

CLAMP 1 CYLINDER

CYLINDEREXTENDED

MR3






SCREW GUIDECYLINDER 1SCREW RESTRAINT

CYLINDER 3



72

Step 2: Clamp 1 Cylinder Extended/Part Present Sensor On, Screw Insertion Queue On/Start Time Delay

Once the clamp is extended, activating MR3, the PLC looks at the screw part presence sensor (IND3). If IND3 detects a part the sequence will continue, if it does not then the sequence will be halted.

When the PLC receives the signal that a part is present, it activates SOL4, which controls the screw insertion queue cylinders. Because there are no sensors on the screw insertion cylinders, a time delay is started to allow the cylinders time to perform their operation. During this step, the screw begins to exit the module and enters the part.

Figure 69. Step 2: Clamp 1 Extended/Part Present Sensor On, Screw Insertion Queue On/Start Time Delay

CLAMP 1EXTENDED

SOL4

FROMSOURCE

SOL2CLAMP 1 CYLINDER

CYLINDEREXTENDED

MR3






BEGINS TO RETRACT


BEGINS TO EXTEND

SCREW RESTRAINTCYLINDER 3

BEGINS TO EXTEND


MR3 ON

CYLINDER 3BEGINS TO

EXTEND

CYLINDER 1BEGINS TO

EXTEND

CYLINDER 2BEGINS TO RETRACT


73

Step 3: Time Delay Ends, Screw Insertion Queue Off/Second Time Delay Starts

When the timer times out, the PLC de-energizes SOL4, which causes the screw feed cylinders to return to their normal positions. This enables the screw behind the one being inserted into the part to push the one in front completely into the part. A second time delay is started to allow the process to complete.

Figure 70. Step 3: Time Delay Ends, Screw Insertion Queue Off/Second Time Delay Starts

CYLINDER 2BEGINS TO

EXTEND

CYLINDER 1BEGINS TORETRACT

CYLINDER 3BEGINS TORETRACT

SOL4

FROMSOURCE

SOL2CLAMP 1 CYLINDER

CYLINDEREXTENDED

MR3






BEGINS TO EXTEND


BEGINS TO RETRACTSCREW RESTRAINTCYLINDER 3BEGINS TO RETRACT



74

Step 4: Second Time Delay Ends, Retract Clamp Cylinder 1

Once the second time delay times out, the PLC de-energizes SOL2 and clamp cylinder 1 retracts. A short time delay will begin to allow the clamp cylinder time to retract.

Figure 71. Step 4: Second time Delay Ends, Retract Clamp Cylinder 1

CYLINDER 2EXTENDED

CLAMP 1BEGINS TORETRACT

CYLINDER 1RETRACTED

CYLINDER 3RETRACTED

SOL4

FROMSOURCE

SOL2

CLAMP 1 CYLINDER

CYLINDEREXTENDED

MR3





SCREW GUIDECYLINDER 2EXTENDED

SCREW GUIDECYLINDER 1RETRACTEDSCREW RESTRAINT

CYLINDER 3RETRACTED



75


When the time delay for the clamp cylinder ends, clamp 1 will be retracted and the cycle ends. The cycle will repeat when the part is removed, a new part put in place, and the start input is received again.


CLAMP 1CYLINDER

RETRACTED

SOL4

FROMSOURCE

SOL2

CLAMP 1 CYLINDER

CYLINDEREXTENDED

MR3






SCREW GUIDECYLINDER 1SCREW RESTRAINT

CYLINDER 3



76

The sequence just described is summarized by sequence diagram in fi gure 73.

SCREW FEED MODULE SEQUENCE OF OPERATION


INPUTS OUTPUTS

0 Start Condition 0 1 0 1 0 0 0 0


2 Clamp 1 Cylinder Extended/Screws present in queue

Screw Insertion Queue on/start fi rst time delay

1 1 1

3 First time delay ends Screw Insertion Queue off/start second time delay

0 0

4 Second time delay ends Retract Clamp Cylinder 1 0 0

5 Clamp 1 Cylinder Retracted 0

End Condition 0 1 0 1 0 0 0 0

Figure 73. Sequence DiagramS

tart

PB

Sto

p P

B

MR

3

IND

3

SO

L2

SO

L4

T1

T2


77

SKILL 6 DESIGN A PLC PROGRAM THAT SEQUENCES A SCREW FEED MODULE

Procedure Overview

In this procedure, you will design and test a PLC program that sequences a screw feed module to insert screws into the valve bodies on the 87-MS5 Servo Robotic Assembly station.

1. Design a PLC program given the following information. The general sequence, I/O diagram, and power diagram are as follows: General Sequence:

1) Pressing the Start pushbutton (PB1) enables the PLC program, energizes the clamp 1 solenoid (SOL2) to extend the cylinder.

2) Once the cylinder is extended (MR3), the PLC looks at IND3 to verify there are screws present in the queue.

3) If IND3 is high, meaning there are screws present, then the PLC turns on SOL4 to activate the screw insertion queue. A timer starts (1 second) to give the queue cylinders time to perform the fi rst part of the insertion.

4) After the time delay ends, SOL4 is turned off and a second time delay (1 second) starts to allow the screw insertion to complete.

5) When the second time delay ends, the cycle ends. It will start again once the Start pushbutton is pressed.

Special Conditions:• Pressing the Stop pushbutton at any time will cause the cylinder to stop (or halt) at the end of its current step. Pressing the Start pushbutton will resume the sequence.• The Start pushbutton lamp will turn off when ready (motor ready signal on) and turn solid as the station is operating.


78



I/O DIAGRAM

I0.0

Q4.6

Q5.0

START INPUTCLAMP 1 EXTEND

(SOL2)

SCREW INSERTION QUEUE(SOL4)

PB

I1.4

MR3CLAMP 1

EXTENDED

OUTPUTSINPUTS

I2.6

IND3SCREW

PRESENT

SOL4

FROMSOURCE

SOL2

CLAMP 1 CYLINDER

CYLINDEREXTENDED

MR3

SCREW INSERTION QUEUE CYLINDERSQUEUE CYLINDER 1

QUEUE CYLINDER 2

QUEUE CYLINDER 3



79

SCREW FEED MODULE SEQUENCE OF OPERATION


INPUTS OUTPUTS



2 Clamp 1 Cylinder Extended/Screws present in queue

Screw Insertion Queue on/start fi rst time delay

1 1 1

3 First time delay ends Screw Insertion Queue off/start second time delay

0 0 1

4 Second time delay ends Retract Clamp Cylinder 1 0 0

5 Clamp 1 Cylinder Retracted 0











E. Save OB1. 4. If the 87-MS5 Servo Robotic Assembly station is connected to another

station, separate the stations. If the 87-MS5 Servo Robotic Assembly station is already disconnected, continue to Step 5.

Sta

rt P

B (

I0.0

)

Sto

p P

B (

I0.1

)

MR

3 (I

1.4)

IND

3 (2

.6)

SO

L2 (

Q4.

6)

SO

L4 (

Q5.

0)

T1

T2


80






Tie up long hair






6. Connect an air supply line to the station’s air manifold quick connect. 7. Plug the station’s power cable into a power outlet. 8. Perform the following substeps to power up the 87-MS5 Servo Robotic

Assembly station.

A. Remove the lockout/tagout device from the electric power source.

B. Remove the lockout/tagout device from the pneumatic power source.

C. Turn on the air to the station by shifting the lever on the lockout valve.

D. Set the station’s air supply regulator to 50 psi/ 345 kPa.

E. Set the screw feed module’s air supply regulator to 12 psi/82.7 kPa.

F. Turn the station’s Main Power Switch to the On position.


81

9. Perform the following substeps to download the project to the PLC.

A. Reset the PLC.



C. Click Yes on the dialog to complete a warm restart. 10. Go online with the processor and monitor the OB1 Block. 11. Manually place a spool into a valve body. 12. Manually place the valve body on the work surface in front of the screw feed

module, as shown in fi gure 78.

Figure 78. Valve Body Replacement

13. Press the Output Power pushbutton to enable the PLC’s outputs. 14. Perform the following substeps to test the PLC program. At this time, the Start pushbutton lamp should be off.

A. Press the Start pushbutton momentarily.

The clamp 1 cylinder should extend to hold the valve body in place.

The start pushbutton lamp should turn on and remain on as this occurs.

VALVE BODY


82

B. Press the Start pushbutton momentarily.

The screw insertion queue solenoid should turn on and insert a screw into the valve body, the solenoid will then turn off and the screw is pushed the rest of the way into the valve body by the other screws in the queue.

C. Press the Start pushbutton, momentarily.

The clamp 1 cylinder should retract.

D. Manually remove the valve body from the work surface. 15. Click the Monitor button to go offl ine from the processor. 16. Use the PLC programming software to place the PLC into Stop mode. 17. Print out a copy of the ladder logic program and place it in your portfolio. It

will be used in your assessment. 18. Perform the following substeps to shut down the 87-MS5 Servo Robotic

Assembly station.




D. Turn the 87-MS5’s main power switch to Off.




83

OBJECTIVE 10 DESCRIBE A SEQUENCE OF OPERATION OF A SCREW THREAD ENGAGEMENT MODULE

Industrial applications often use screw thread engagement modules, like the one shown in fi gure 79 to start the screw threads of one part into its mating part to prevent loss of either part during transport to the next workstation in the assembly process.

In the example shown in fi gure 79, the PLC uses one signal to actuate the single-solenoid directional control valve to extend the cylinder (SOL6) and to start the motor starter (M1).

Figure 79. Screw Thread Engagement Module Construction

SINGLE-SOLENOIDDCV

(SOL3)

SINGLE-SOLENOIDDCV

(SOL6)

NON-SLIPSURFACE

SCREW HEAD

VALVEASSEMBLY

NON-SLIPSURFACE

KNOBCYLINDER

MAGNETICREED

SWITCHES

MR6 MR5

MOTOR(M1)

CLAMP 2CYLINDER

MR2

KNOB

SPRING


84

Screw Thread Engagement modules are typically PLC controlled. The sequence will be similar to that shown in the table below.

SCREW THREAD ENGAGEMENT MODULE SEQUENCE OF EVENTS

STEP INPUT OUTPUT

1 Receive Start Input (S1 on) Extend Clamp 2 (SOL3 on)

2 Clamp 2 Extended (MR4 on) Extend Knob Cylinder/Start Motor (SOL6, M1 on)

3 Knob Cylinder Extended (MR5 on) Start time delay (Thread engage-ment timer starts)

4 Time Delay Ends (Thread engage-ment timer done)

Turn Screw Motor Off/Retract Knob Cylinder

5 Knob Cylinder Retracted (MR1 on) Retract Clamp 2


Figure 80. Screw Thread Engagement Module Sequence of Operation


85

Initial Condition

The screw thread engagement module must be in some pre-determined state before any sequence may take place. Many times this will be a state in which the clamp cylinder and the knob cylinder are retracted and the motor is off. In some cases, there may be an interlock indicating that motion at the source and/or desti-nation station has stopped and it is now safe to transfer. One example would be that the source station’s transfer table has stopped moving. If these initial condi-tions are not satisfi ed, the screw thread engagement module will not operate and the PLC controlling the module may even provide an alarm light or message to the operator, indicating that operator intervention is necessary.

Note the quick exhaust shown on the power diagram for the clamp 2 cylinder. The clamp cylinder is a spring return cylinder and it must retract quickly so it does not interfere with the robot. The quick exhaust allows the air to leave the cylinder quickly, reducing the amount of pressure the cylinder has to overcome. This enables the cylinder to retract more quickly than it would without the quick exhaust.


FROMSOURCE

SOL3 CLAMP 2 CYLINDER

CYLINDEREXTENDED

MR4

QUICKEXHAUST

KNOB ASSEMBLY CYLINDER

CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6SOL6

24 VDC

GND

M1

M1 SCREW MOTOR

CYLINDERRETRACTED

MOTOROFF

CLAMPRETRACTED

MR6 ON


86

Step 1: Receive Start Input, Extend Clamp 2

In this step, the PLC controlling the screw thread engagement module sequence receives an input to start the screw thread engagement sequence. The input may be from another workstation, and operator, or the manipulator tending the module. After receiving the input signal, the PLC turns on SOL3 to extend clamp 2. The clamp will hold the part in place while work is being performed on it.

Figure 82. Step 1: Receive Start Input, Extend Clamp 2

FROMSOURCE

SOL3

CLAMP 2 CYLINDER

CYLINDEREXTENDED

MR4

QUICKEXHAUST


CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6SOL6

24 VDC

GND

M1

M1 SCREW MOTOR

CLAMP 2 BEGINSTO EXTEND


87

Step 2: Clamp 2 Extended, Extend Knob Cylinder/Start Screw Motor

Once clamp 2 is extended (MR4 on), the PLC will send an output to both extend the knob cylinder (SOL6 on) and turn the screw motor on (M1 on).

Figure 83. Step 2: Clamp 2 Extended, Extend Knob Cylinder/Start Screw Motor

FROMSOURCE

SOL3

CLAMP 2 CYLINDER

CYLINDEREXTENDED

MR4

QUICKEXHAUST


CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6

SOL6

24 VDC

GND

M1

M1 SCREW MOTOR

MR4 ON

CYLINDERBEGINS TO

EXTEND MOTORON


88

Step 3: Knob Cylinder Extended, Start Time Delay

After the knob cylinder has extended (MR5 on), a time delay is started to allow the motor time to turn the screw head so that the threads engage in the knob.

Figure 84. Step 3: Knob Cylinder Extended, Start Time Delay

FROMSOURCE

SOL3

CLAMP 2 CYLINDER

CYLINDEREXTENDED

MR4

QUICKEXHAUST


CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6

SOL6

24 VDC

GND

M1

M1 SCREW MOTOR

MR5 ON

MR6 OFF


89

Step 4: Time Delay Times Out, Turn Screw Motor Off/Retract Knob Cylinder

When the timer times out, the PLC turns off the output to SOL6 and M1, which allows the knob cylinder to retract and turns off the screw motor. The screw threads should be engaged in the knob at this time.

Figure 85. Step 4: Time Delay Times Out, Turn Screw Motor Off/Retract Knob Cylinder

FROMSOURCE

SOL3

CLAMP 2 CYLINDER

CYLINDEREXTENDED

MR4

QUICKEXHAUST


CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6SOL6

24 VDC

GND

M1

M1 SCREW MOTOR

CYLINDERBEGINS TORETRACT

MOTOROFF


90

Step 5: Knob Cylinder Retracted, Retract Clamp 2

Once the knob cylinder is retracted (MR6 on), the PLC de-energizes SOL3 and clamp 2 retracts. A short time delay allows the clamp time to fully retract.

Figure 86. Step 5: Knob Cylinder Retracted, Retract Clamp 2

FROMSOURCE


CYLINDEREXTENDED

MR4

QUICKEXHAUST


CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6SOL6

24 VDC

GND

M1

M1 SCREW MOTOR

CLAMP 2 BEGINSTO RETRACT

MR6 ON

CYLINDERRETRACTED

MR5OFF


91


When the short clamp timer ends, the clamp is retracted and the cycle ends. The cycle will repeat when the completed assembly is removed, new parts placed in the module, and the start input is received again.


The sequence just described is summarized by sequence diagram in fi gure 88.

SCREW THREAD ENGAGEMENT MODULE SEQUENCE OF OPERATIONS


INPUTS OUTPUTS


1 Receive Start Input Extend Clamp 2 1/0 1

2 Clamp 2 Extended Extend Knob Cylinder/Start Motor 1 1

3 Knob Cylinder Extended Start Time Delay 1 0 1

4 Time Delay Ends Turn Bolt Motor Off/Retract Knob Cylinder 0 0

5 Knob Cylinder Retracted Retract Clamp 2/Cycle Repeats 0 1 0

6 Clamp 2 Retracted Cycle Ends 0



Sta

rt P

B

Sto

p P

B

MR

4

MR

5

MR

6

SO

L3

SO

L6/M

1

T1

FROMSOURCE


CYLINDEREXTENDED

MR4

QUICKEXHAUST


CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6SOL6

24 VDC

GND

M1

M1 SCREW MOTOR

SCREW AND KNOBTHREADSENGAGED

CLAMPRETRACTED


92

SKILL 7 DESIGN A PLC PROGRAM THAT SEQUENCES A SCREW THREAD ENGAGEMENT MODULE

Procedure Overview

In this procedure, you will design and test a PLC program that uses a screw thread engagement module to engage the threads of the screw into the knob to hold the parts together for transport to the next workstation.


1) Pressing the Start pushbutton (PB1) enables the PLC program.

2) After clamp 2 is extended (MR4 on), SOL6 is energized, which extends the knob cylinder and turns on the bolt motor (M1).

3) Once the knob cylinder is extended (MR5 on), a short dwell timer (3 seconds) is started to allow the screw threads time to engage in the knob.

4) After the timer ends, the knob cylinder retracts and the bolt motor is shut off.

5) When the knob cylinder is fully retracted (MR6 on), SOL3 is de-energized allowing clamp 2 to retract. A short timer (1 second) is started to allow time for the cylinder to retract.

Special Conditions:• The Start pushbutton lamp will be off when the station is in its home posi-tion (clamp retracted, knob cylinder retracted). The Start pushbutton will turn solid as the station is operating. • Pressing the Stop pushbutton at any time will cause the station to stop (or halt) at the end of its current step. Pressing the Start pushbutton will resume the sequence from that step.


93



I/O DIAGRAM

I0.0

Q4.7

Q5.2

START INPUTCLAMP 2 EXTEND

(SOL3)

KNOB ASSEMBLY EXTEND/MOTOR STARTER ON

(SOL6)

PB

I1.5

MR4CLAMP 2

EXTENDED

OUTPUTSINPUTS

I2.0

MR5KNOB ASSEMBLY

EXTENDED

I2.1

MR6KNOB ASSEMBLY

RETRACTED

M1

SOL6

KNOB ASSEMBLY VALVE

FROMSOURCE

CYLINDEREXTENDED

MR5

SOL3 CLAMP 2 VALVE

CYLINDEREXTENDED

MR4

QUICKEXHAUST

CYLINDERRETRACTED

MR6

24 VDC

GND

M1

M1 SCREW MOTOR


94

SCREW THREAD ENGAGEMENT MODULE SEQUENCE OF OPERATIONS


INPUTS OUTPUTS


1 Receive Start Input Extend Clamp 2 1/0 1

2 Clamp 2 Extended Extend Knob Cylinder/Start Motor 1 1

3 Knob Cylinder Extended Start Time Delay 1 0 1

4 Time Delay Ends Turn Bolt Motor Off/Retract Knob Cylinder 0 0

5 Knob Cylinder Retracted Retract Clamp 2 0 1 0

6 Clamp 2 Retracted Cycle Ends 0













Sta

rt P

B (

I0.0

)

Sto

p P

B (

I0.1

)

MR

4 (I

1.5)

MR

5 (I

2.0)

MR

6 (I

2.1)

SO

L3 (

Q4.

7)

SO

L6/M

1 (Q

5.2)

T1


95






Tie up long hair






6. Connect an air supply line to the station’s air manifold quick connect. 7. Plug the station’s power cable into a power outlet. 8. Perform the following substeps to power up the 87-MS5 Servo Robotic

Assembly station.





E. Set the screw feed module’s air supply to 12 psi/82.7 kPa.

F. Turn the station’s Main Power Switch to the On position. 9. Press the Output Power pushbutton to enable the PLC’s outputs. 10. Perform the following substeps to download the project to the PLC.

A. Reset the PLC.



E. Click Yes on the dialog to complete a warm restart. 11. Go online with the processor and monitor the OB1 Block. 12. Manually assemble a valve body with a spool and a screw.


96

13. Manually place the valve body assembly in the recess provided on the work surface, as shown in fi gure 93.

At this time, the Start pushbutton indicator should be off indicating that the station is ready to run.

Figure 93. Valve Body and Knob/Spring Assembly Placement

14. Manually place a knob/spring assembly on the assembly fi xture as shown in fi gure 93.

15. Press the Start pushbutton momentarily. The clamp 2 cylinder should extend to hold the valve body. 16. Press the Start pushbutton momentarily. The screw motor should start running and the knob assembly cylinder should

extend, pushing the knob/spring assembly to join the screw of the valve body assembly.

17. Press the Start pushbutton momentarily. The motor should turn off and the knob assembly cylinder should retract. 18. Press the Start pushbutton momentarily. The clamp cylinder should retract. 19. Manually remove the assembly and verify the knob is threaded on the screw. 20. Click the Monitor button to go offl ine from the processor. 21. Use the PLC programming software to place the PLC into Stop mode.

KNOB/SPRINGASSEMBLY

VALVEASSEMBLY


97

22. Print out a copy of the ladder logic program and place it in your portfolio. It will be used in your assessment.

23. Perform the following substeps to shut down the 87-MS5 Servo Robotic Assembly station.








98


1. One type of part insertion module uses a _____ to push parts into assemblies.

2. The part insertion module must be in some pre-determined state before any _____ can take place.

3. Screw feed modules are typically equipped with a _____ to detect the presence of screws.

4. Screw feed modules are typically _____ controlled.

5. Industrial applications often use a screw thread engagement module to start the screw threads into its _______ part.

6. Before the sequence can begin for a screw thread engagement module, the _____ cylinder and the knob cylinder must be retracted and the motor must be off.


99

SEGMENT 4STATION SEQUENCING

OBJECTIVE 11 DESCRIBE A SEQUENCE OF OPERATION OF A SERVO ROBOTIC ASSEMBLY STATION

The operation of a servo robotic assembly station typically combines several different assembly modules and one or more material handling devices all controlled by a single PLC program.

An example of a servo robotic assembly station is shown in fi gure 94. This station is designed to insert a spool and screw into a valve assembly. A shuttle then moves the assembly to the screw thread engagement module where a knob and spring assembly is threaded onto the previously inserted screw. A servo robot places the valve body at the spool/screw insertion module, a knob and spring assembly at the screw thread engagement module, and removes the completed assembly to the next operation.

Figure 94. Servo Robot Assembly Station

SERVO ROBOT

SCREW AND SPOOLINSERTION MODULES

SCREW THREADENGAGEMENT

MODULE


100

A typical servo robotic assembly stations sequence is similar to that shown in fi gure 95. This sequence is a combination of the spool insertion module, screw feed module, and the screw thread engagement module.

SERVO ROBOTIC ASSEMBLY STATION SEQUENCE OF EVENTS

STEP INPUT OUTPUT

1 Robot Receives Reset Signal (Robot Reset on)

Robot Places Knob/Spring Assembly (Robot Signal 1 on)

2 Robot Sends Ready Signal/PLC Receives Start Input (Robot Ready, S1 on)

Robot Places Valve Body (Robot Signal 2 on)

3 Robot Sends Ready Signal (Robot Ready on)

Extend Clamp 1 (SOL2 on)

4 Clamp 1 Extended (MR3 on) Extend Spool Insertion Cylinder (SOL1 on)

5 Spool Insertion Cylinder Extended/Screws Present in Queue (MR1, IND3 on)

Screw Feeder Queue On/Start First Time Delay (SOL4 on, Screw Insert Time Delay 1 Starts)

6 First Time Delay Ends (Screw Timer 1 Done)

Retract Spool Insertion Cylinder/Screw Feeder Queue Off/Start Sec-ond Time Delay (Screw Insert Time Delay 2 Starts)

7 Second Time Delay Ends/Spool Insertion Cylinder Retracted (Screw Timer 2 Done, MR2 on)

Retract Clamp 1/Extend Transport Cylinder (SOL5 on)

8 Clamp 1 Retracted/Transport Cylinder Extended (LS1 on)

Retract Transport Cylinder

9 Transport Cylinder Retracted (LS2 on)

Extend Clamp 2 (SOL3 on)

10 Clamp 2 Extended (MR4 on) Extend Knob Cylinder/Start Bolt Mo-tor (SOL6, M1 on)

11 Knob Cylinder Extended (MR5 on) Start Time Delay (Thread Engage-ment Timer Starts)

12 Time Delay Ends (Thread Engage-ment Timer Done)

Retract Knob Cylinder/Turn Motor Off

13 Knob Cylinder Retracted (MR6 on) Retract Clamp 2

14 Clamp 2 Retracted Assembly Complete/Robot Pick Up Assembly (Robot Signal 3 on)

15 Robot Ready Signal (Robot Ready on)

Cycle Ends

Figure 95. Sequence of Operations


101

SKILL 8 DESIGN A PLC PROGRAM THAT SEQUENCES A SERVO ROBOTIC ASSEMBLY STATION

Procedure Overview

In this procedure, you will design and test a PLC program that uses a part feeder, automatic screw feeder, part insertion module, screw feed module, and a screw thread engagement module to assemble a valve body as it progresses through the station.


1) Pressing the Start pushbutton (PB1) enables the PLC program, which turns on the Active lamp indicator and sends a signal to the robot, which will place a knob/spring assembly and go back to its ready state before then picking up and placing a valve body.

2) The robot ready signal causes the Clamp 1 cylinder to extend.

3) After the Clamp 1 cylinder is extended, indicated by MR3, the spool inser-tion cylinder is extended.

4) After the spool insertion cylinder is extended (MR1 on), the PLC looks at IND3 to verify there are screws present in the queue.


6) After the time delay ends, SOL1 is de-energized, which retracts the spool insertion cylinder and SOL4 is turned off. A second time delay (1 second) starts to allow the screw insertion to complete.

7) When the second time delay ends, the clamp retracts.

8) The transport cylinder solenoid (SOL5) is energized, which causes the cylinder to extend, shuttling the part to the next module.

9) Once the transport is extended (LS1 on), it retracts.

10) When LS2 is on (cylinder retracted), SOL3 is energized to extend clamp 2.

11) After clamp 2 is extended (MR4 on), SOL6 is energized, which extends the knob cylinder and turns on the screw motor (M1).


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13) After the timer ends, the knob cylinder retracts and the screw motor is shut off.

14) When the knob cylinder is fully retracted (MR6 on), SOL3 is de-energized allowing clamp 2 to retract. A short timer (1 second) is started to allow time for the cylinder to retract.

15) Once the timer times out, the PLC signals the robot that the assembly is ready to be removed from the station.

Special Conditions:• The Start pushbutton lamp will be off when the station is in its home position (robot ready, spool feeder retracted, clamps retracted, transport retracted, and knob cylinder retracted/motor off). The Start pushbutton will turn solid as the station is operating.• Pressing the Stop pushbutton at any time will cause the station to stop (or halt) at the end of its current step. Pressing the Start pushbutton will resume the sequence from that step.


103


I/O DIAGRAM

I0.0 Q4.0

Q4.5

Q4.6

Q4.7

Q5.0

Q5.1

I0.1

START

I1.0

I1.1

I1.3

MR2

ACTIVELAMP

SPOOL INSERTION(SOL 1)

CLAMP 1 EXTEND(SOL 2)

CLAMP 2 EXTEND(SOL 3)

SCREW INSERTION QUEUE(SOL 4)

PB1

PB2

I1.2

MR1

I1.4

MR3

I1.5

MR4

I2.0

MR5

SPOOL INSERTION

RETRACTED

SPOOL INSERTIONEXTENDED

CLAMP 1EXTENDED

CLAMP 2EXTENDED

KNOB ASSEMBLYEXTENDED

I2.1

MR6KNOB ASSEMBLY

RETRACTED

Q5.3

SELECT 3-WAY SPOOL(SOL 7A)

STOP

RESET

AUTO

I2.2

MR7SPOOL FEEDER

EXTENDED

I2.3

MR8SPOOL FEEDER

RETRACTED

I2.7

ROBOT READYHANDSHAKE

TRANSPORT EXTEND(SOL 5)

Q5.4

SELECT 4-WAY SPOOL(SOL 7B)

Q5.5

ROBOT HANDSHAKERESET

Q5.6

ROBOT HANDSHAKEGET VALVE BODY

I1.6LS1

TRANSPORTEXTENDED

I1.7LS2

TRANSPORTRETRACTED

I2.4

IND13-WAY SPOOL

PRESENT

I2.5

IND24-WAY SPOOL

PRESENT

I2.6

IND33RD SCREW

PRESENT

Q5.2

KNOB ASSEMBLY EXTEND(SOL 6)

M1SCREW MOTOR ON

Q5.7

ROBOT HANDSHAKEBODY SELECT/OFF LOAD


104


SOL4

FROMSOURCE

SOL1


CYLINDEREXTENDED

MR1

SCREW INSERTION QUEUE CYLINDER

SCREW GUIDE QUEUE CYLINDER 1





CYLINDEREXTENDED

MR4

QUICKEXHAUST

SOL2

CLAMP 1 CYLINDER

CYLINDEREXTENDED

MR3

CYLINDERRETRACTED

MR2

KNOB ASSEMBLY VALVE

CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6

SPOOL FEEDER

CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6

SOL6

SOL7A

TRANSPORT VALVE

CYLINDEREXTENDED

LS1

CYLINDERRETRACTED

LS2SOL5

SOL7B

24 VDC

GND

M1

M1 SCREW MOTOR

QUICKEXHAUST

QUICKEXHAUST


105



106
















Tie up long hair






6. Connect an air supply line to the station’s air manifold quick connect. 7. Plug the station’s power cable into a power outlet. 8. Verify the feed stand and the parts bin have been installed on the station. If

they have not, then install them. 9. Stock all of the part feeders.


107

10. Perform the following substeps to power up the 87-MS5 Servo Robotic Assembly station.





E. Set the screw feed module’s air supply regulator to 12 psi/82.7 kPa.

F. Turn the station’s Main Power switch to the On position. 11. Press the Output Power pushbutton to enable the PLC’s outputs. 12. Perform the following substeps to start up the robot.

A. Turn on the power to the robot controller.



This is mech.prg for the Pegasus or Saturn.prg for the Saturn.



F. Home the robot. 13. Teach the pickup points for the parts as shown in fi gure 100.


APPROACH 2

GRIP 3


108

You will only use the right side (when facing the feed stand) location. The function of each teach point is described as follows:

• Point 2 is a approach point above the valve body• Point 3 is a grip point for grasping the valve bodyThis point must be taught with the valve body placed in the robot gripper.

14. Perform the following substeps to run the robot program using the teach pendant or proceed to Step 15 to run the program using the Robot Control software.


B. Press [F1] STR.





The robot will retrieve a knob/spring assembly from the feeder and place it in the assembly fi xture, and then move to a wait position.

15. Click on the Run button shown in the File Control toolbar. The robot will retrieve a knob/spring assembly from the feeder and place it in

the assembly fi xture, and then move to a wait position. 16. Use the DCVs’ manual overrides to home the pneumatic cylinders (robot

ready, spool feeder retracted, clamps retracted, transport retracted, knob cylinder retracted and motor off).

17. Perform the following substeps to download the project to the PLC.

A. Reset the PLC.



C. Click Yes on the dialog to complete a warm restart. 18. Go online with the processor and monitor the OB1 Block.


109

19. Manually place a good acrylic valve body in the recess provided on the feed stand, as shown in fi gure 101.

This should have no effect on the Servo Robotic Assembly station, as the Start pushbutton has not yet been pressed.

Figure 101. Valve Body Placement

20. Press and release the Start pushbutton. The robot should start and the Start pushbutton’s active indicator should turn

on indicating that the station is running. The following sequence should occur.

• The robot places the knob/spring assembly and then it will place a valve body and return to its ready position• Clamp 1 will extend and the spool insertion cylinder will extend, pushing a spool into the valve body• The screw insertion module will insert the screw part way into the spool• The spool insertion cylinder will then retract and the screw insertion module will complete inserting the screw into the spool• Clamp 1 will retract and the transport will shuttle the part to the knob/spring assembly area• Clamp 2 will extend• The screw motor will turn on and the knob/spring cylinder will extend and push the knob toward the valve body causing the screwdriver bit to engage the screw head• After a 3 second dwell time, the motor will turn off and the knob/spring cylinder will retract• Clamp 2 will retract


110

• The robot picks up the valve assembly and places it in the parts bin at the end of the station and then places another knob/spring assembly before it returns to its ready position

21. Place a good aluminum valve body in the recess provided on the feed stand. 22. Press and release the Start pushbutton. The same sequence should occur. 23. Place another good aluminum valve body in the recess provided on the feed

stand. 24. Press and release the Start pushbutton. 25. Once the Servo Robotic Assembly station begins operation, press the Stop

pushbutton to stop (or halt) the station after its current step. Once movement is complete, the station should stop. 26. Press the Start pushbutton. The station should resume operation from its current step. 27. Click the Monitor button to go offl ine from the processor. 28. Use the PLC programming software to place the PLC into Stop mode. 29. Print out a copy of the ladder logic program and place it in your portfolio. It

will be used in your assessment. 30. Perform the following substeps to shutdown the robot controller and Robot

Control software.

A. Move the robot to the home position.

B. Disable the Robot’s drives.

C. Close the Robot’s Control software.

D. Turn off the robot controller. 31. Perform the following substeps to shut down the 87-MS5 Servo Robotic

Assembly station.








111

OBJECTIVE 12 DESCRIBE THE OPERATION OF A SERVO ROBOTIC ASSEMBLY STATION WITH MANUAL/ AUTO/ RESET FUNCTIONS

Traditional operator panels usually include 2-position or 3-position selector switches to select the mode of operation, as shown in fi gure 102. Some of the modes that can be selected are Off, Manual, Automatic, and Reset.

Figure 102. Operator Panel with Selector Switches

AUTOMATIC

Selecting the automatic mode causes the PLC program to disable the manual functions and enable the automatic functions. This is usually done by disabling a manual function or function block and enabling an automatic function or function block.

After automatic mode is selected, certain initial conditions are usually required to be satisfi ed before the station’s sequence can begin. These initial conditions are input signals monitored by the PLC to verify that the station’s parts are in the home position and to verify that a part is present and ready to be processed. If the station’s parts are not in the proper position, a visual indicator is usually displayed on the operator panel to indicate that the station is not in its home position. If the station’s parts are not homed, the operator must either switch to manual mode and reposition the parts, or initiate a reset function to home the station.

After the machine is homed and the automatic mode is selected, pressing a start pushbutton causes the station to perform its sequence automatically. After the sequence has been completed, the station repeats the cycle.


112

MANUAL

Selecting the manual mode causes the PLC program to enable the machine’s manual functions. This is usually done in program logic by enabling a function or function block containing the manual operations while disabling functions and/or function blocks supporting the machine’s other operating modes.

Placing a machine in manual mode enables the user to move the machine’s actuators on an as needed basis and is rarely used for production purposes. Because of this, the manual mode is usually associated with maintenance operations. Main-tenance personnel may use the manual mode to: test the operation of a machine, make adjustments to the machine and/or its sensors, or to recover from a machine malfunction. There are two versions of manual operation: standard manual opera-tion and step.

• Manual (traditional) - In this version of manual operation, turning the selector switch to the Manual position typically enables pushbuttons and/or other manual operators on the operator panel to be used to manipulate the machine’s actuators. In the case of an assembly station, for example, the operator panel (or HMI) could have two pushbuttons for each of the station’s cylinders, one to make the actuator extend and one to make it retract.• Step - In this version of manual operation, a pushbutton or other manual operator is used to step the machine through the steps of its sequence, one step at a time. In the case of a robotic assembly application, pressing the pushbutton the fi rst time would cause the robot to place the parts. Pressing the pushbutton a second time would cause the spool insertion cylinder to extend, and so forth.

RESET

A reset function is included in the PLC program to home the station. The PLC program is designed to return all actuators to their start positions when a selector switch is placed in the Reset position.

The reset function can be programmed to cause all of the actuators to return to their start positions at the same time or it can be programmed to return them in a sequence. Depending on the physical layout of the station, returning all of the actuators at the same time may cause some actuators to interfere with others. In this case, the reset function must be programmed to perform a reset sequence. Using a sequence causes the actuators to return to the home position in an order that prevents interference with other actuators.


113

For example, a Servo Robotic Assembly station’s spool insertion cylinder is extended. After the cylinder is extended, the cylinder is retracted so that the next part does not contact the cylinder. When all of the stations parts are in the home position, an indicator is provided on the operator panel. The indicator may be a dedi-cated Home lamp, or solid, off, or fl ashing indicators on the panel’s pushbuttons.

Figure 103. Servo Robotic Assembly Station in Reset Position


114

SKILL 9 DESIGN A PLC PROGRAM THAT PROVIDES MANUAL/ AUTO/ RESET FUNCTIONS FOR A SERVO ROBOTIC ASSEMBLY STATION

Procedure Overview

In this procedure, you will modify project L7S7XXX to add the Manual, Auto, and Reset Functions.

1. Modify project L7S7AXXX so as to provide the Manual, Auto, and Reset functions to the program.

The general sequence, I/O diagram, and power diagram are as follows: General Sequence (Auto Mode):

1) Pressing the Start pushbutton (PB1) enables the PLC program, which turns on the Active lamp indicator and sends a signal to the robot, which will place a knob/spring assembly and then pick up and place a valve body.

2) The robot ready signal causes the Clamp 1 cylinder to extend.

3) After the Clamp 1 cylinder is extended, indicated by MR3, the spool inser-tion cylinder is extended.

4) After the spool insertion cylinder is extended (MR1), the PLC looks at IND3 to verify there are screws present in the queue.


6) After the time delay ends, SOL1 is de-energized, which retracts the spool insertion cylinder and SOL4 is turned off. A second time delay (1 second) starts to allow the screw insertion to complete.

7) When the second time delay ends, the clamp retracts.

8) The transport cylinder solenoid (SOL5) is energized, which causes the cylinder to extend, shuttling the part to the next module.

9) Once the transport is extended (LS1 on), it retracts.

10) When LS2 is on (cylinder retracted), SOL3 is energized to extend clamp 2.

11) After clamp 2 is extended (MR4 on), SOL6 is energized, which extends the knob cylinder and turns on the screw motor (M1).



115

13) After the timer ends, the knob cylinder retracts and the screw motor is shut off.

14) When the knob cylinder is fully retracted (MR6 on), SOL 3 is de-ener-gized allowing clamp 2 to retract. A short timer (1 second) is started to allow time for the cylinder to retract.

15) Once the timer times out, the PLC signals the robot that the assembly is ready to be removed from the station.

Special Conditions: (Auto Mode)

• The sequence cannot be started unless all cylinders are homed, the robot is ready, and the motor is off.• The Start pushbutton lamp will be off when the system is reset. The Start pushbutton will turn solid as the station is operating.• Pressing the Stop pushbutton at any time will cause the Servo Robotic Assembly station to stop (or halt) at the end of its current step. Pressing the Start pushbutton will resume the sequence from that step.

(Manual Mode) Pressing the Start pushbutton while the selector switch is in the Manual

position causes the Servo Robotic Assembly station to step-through its sequence, one step at a time.

(Reset) Turning the selector switch to the Reset position causes the Servo Robotic

Assembly station to reset its actuators and the queue counts.


116


I/O DIAGRAM

I0.0 Q4.0

Q4.5

Q4.6

Q4.7

Q5.0

Q5.1

I0.1

START

I1.0

I1.1

I1.3

MR2

ACTIVELAMP

SPOOL INSERTION(SOL1)

CLAMP 1 EXTEND(SOL2)

CLAMP 2 EXTEND(SOL3)

SCREW INSERTION QUEUE(SOL4)

PB1

PB2

I1.2

MR1

I1.4

MR3

I1.5

MR4

I2.0

MR5

SPOOL INSERTION

RETRACTED

SPOOL INSERTIONEXTENDED

CLAMP 1EXTENDED

CLAMP 2EXTENDED

KNOB ASSEMBLYEXTENDED

I2.1

MR6KNOB ASSEMBLY

RETRACTED

Q5.3

SELECT 3-WAY SPOOL(SOL7A)

STOP

RESET

AUTO

I2.2

MR7SPOOL FEEDER

EXTENDED

I2.3

MR8SPOOL FEEDER

RETRACTED

I2.7

ROBOT READYHANDSHAKE

TRANSPORT EXTEND(SOL5)

Q5.4

SELECT 4-WAY SPOOL(SOL7B)

Q5.5

ROBOT HANDSHAKERESET

Q5.6

ROBOT HANDSHAKEGET VALVE BODY

I1.6LS1

TRANSPORTEXTENDED

I1.7LS2

TRANSPORTRETRACTED

I2.4

IND13-WAY SPOOL

PRESENT

I2.5

IND24-WAY SPOOL

PRESENT

I2.6

IND33RD SCREW

PRESENT

Q5.2

KNOB ASSEMBLY EXTEND(SOL6)

M1SCREW MOTOR ON

Q5.7

ROBOT HANDSHAKEBODY SELECT/OFF LOAD


117


SOL4

FROMSOURCE

SOL1


CYLINDEREXTENDED

MR1

SCREW INSERTION QUEUE CYLINDER






CYLINDEREXTENDED

MR4

QUICKEXHAUST

SOL2

CLAMP 1 CYLINDER

CYLINDEREXTENDED

MR3

CYLINDERRETRACTED

MR2

KNOB ASSEMBLY VALVE

CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6

SPOOL FEEDER

CYLINDEREXTENDED

MR5

CYLINDERRETRACTED

MR6

SOL6

SOL7A

TRANSPORT VALVE

CYLINDEREXTENDED

LS1

CYLINDERRETRACTED

LS2SOL5

SOL7B

24 VDC

GND

M1

M1 SCREW MOTOR


118



119





A. Open Project L7S7XXX.

B. Save the Project as L7S8XXX where XXX represents your initials.

C. Enter the program that you developed in Step 1.

D. Organize the program into function blocks according to mode (e.g. auto, reset, and manual).

E. Save your project. 4. If the 87-MS5 Servo Robotic Assembly station is connected to another 87-

MS station, separate the stations. If the 87-MS5 Servo Robotic Assembly station is already disconnected, continue to Step 5.






Tie up long hair






6. Connect an air supply line to the station’s air manifold quick connect. 7. Plug the station’s power cable into a power outlet. 8. Remove any valve bodies or knob/spring assemblies that are currently on the

work surface. 9. Verify the feed stand and the parts bin have been installed on the station. If

they have not, then install them. 10. Stock all of the parts feeders.


120

11. Perform the following substeps to power up the 87-MS5 Servo Robotic Assembly station.

A. Place the Mode selector switch in the Manual position.

B. Remove the lockout/tagout device from the electric power source.


D. Turn on the air to the station by shifting the lever on the lockout valve.


F. Set the screw feed module’s air supply regulator to 12 psi/82.7 kPa.

G. Turn the station’s Main Power switch to the On position. 12. Perform the following substeps to download the project to the PLC.

A. Place the PLC power supply switch in the On position.

B. Place the Mode Selector Switch in the Run position.

C. Reset the PLC.

D. Download the SIMATIC 300 Station object to the PLC.

E. Several dialogs will appear during the download. Click the appropriate response to continue downloading the program. The last dialog should ask if you wish to perform a complete (Warm) restart.

F. Click Yes on the dialog to complete a warm restart. 13. Go online with the processor and monitor the project. 14. Press the Output Power pushbutton to enable the PLC’s outputs. 15. Perform the following substeps to start up the robot.

A. Turn on the power to the robot controller.



This is mech.prg for the Pegasus or Saturn.prg for the Saturn.



F. Home the robot.


121

16. Teach the pickup points for the parts, as shown in fi gure 108.


You will only use the right side (when facing the feed stand) location. The function of each teach point is described as follows:

• Point 2 is a hover point above the valve body\• Point 3 is an approach point for grasping the valve body

This point must be taught with the valve body placed in the robot gripper. 17. Perform the following substeps to run a robot program using the teach pendant

or proceed to Step 18 to run the program using the Robot Control software.


B. Press [F1] STR.





APPROACH 2

GRIP 3


122

18. Click on the Run button shown in the File Control toolbar. 19. Perform the following substeps to test the operation of the program.

A. Turn the Mode Selector switch to Reset to return the Servo Robotic Assembly station to its home position.

The cylinders should all be retracted. After the station is homed, the Start pushbutton light should turn off.

B. Turn the Mode Selector switch to the Auto position.

C. Manually place a good acrylic valve body in the recess provided on the Feed Stand.

D. Press and release the Start pushbutton.

The following sequence should occur.• The robot places the knob/spring assembly and then it will place a valve body and return to its ready position• Clamp 1 will extend and the spool insertion cylinder will extend, pushing a spool into the valve body• The screw insertion module will insert the screw part way into the spool• The spool insertion cylinder will then retract and the screw insertion module will complete inserting the screw into the spool• Clamp 1 will retract and the transport will shuttle the part to the knob/spring assembly area• Clamp 2 will extend• The screw motor will turn on and the knob/spring cylinder will extend and push the knob toward the valve body causing the screwdriver bit to engage the screw head• After a 3 second dwell time, the motor will turn off and the knob/spring cylinder will retract• Clamp 2 will retract• The robot picks up the valve assembly and places it in the parts bin at the end of the station and then places another knob/spring assembly before it returns to its ready position

20. Perform the following substeps to test the operation of the station in Manual mode.

A. Turn the Mode Selector switch to the Manual position.

B. Press the Start pushbutton momentarily to activate Step 1 of the sequence.

After receiving the input signal from the Start pushbutton, the robot will move to the acrylic part, pick it up, and place it in the spool insertion module.

C. Press the Start pushbutton momentarily to activate Step 2 of the sequence.

Pushing the Start pushbutton will cause the PLC to activate SOL2 and extend clamp cylinder 1 to hold the valve in place.


123

D. Press the Start pushbutton momentarily to activate Step 3 of the sequence.

The PLC will energize SOL1 to extend the spool insertion cylinder, which pushes the spool into the valve body.

E. Press the Start pushbutton momentarily to activate Step 4 of the sequence.

The PLC energizes SOL4, which activates the screw insertion module queue. The queue releases a screw and it feeds part way into the spool, but keeps it from going completely into the spool, as it would hit the spool insertion cylinder.

F. Press the Start pushbutton momentarily to activate Step 5 of the sequence.

The PLC de-energizes SOL1 and the spool insertion cylinder is retracted. Once the retract limit switch is made, SOL4 is turned off allowing the screw insertion queue to release the screw. The next screw in line is actu-ally pushing the bolt into the spool. The queue cylinder prevents the next screw from extending into the assembly area.

G. Press the Start pushbutton momentarily to activate Step 6 of the sequence.

The PLC de-energizes SOL2 and clamp cylinder 1 retracts.

H. Press the Start pushbutton momentarily to activate Step 7 of the sequence.

SOL5 is energized and the transport cylinder extends, pushing the partial assembly on to the knob/spring assembly module.

I. Press the Start pushbutton momentarily to activate Step 8 of the sequence.

SOL5 is de-energized and the transport cylinder retracts.

J. Press the Start pushbutton momentarily to activate Step 9 of the sequence.

The PLC energizes SOL3, which causes clamp cylinder 2 to extend to hold the valve body in place during the knob/spring assembly process.

K. Press the Start pushbutton momentarily to activate Step 10 of the sequence.

SOL6 is energized and the knob assembly cylinder extends. The screw motor also turns on. The cylinder pushes the knob/spring assembly into the spool while the rotating motor shaft engages the screw head, turning it to thread the screw into the knob. The motor will turn until the knob cylinder reaches the extend switch. This indicates that the knob threads have engaged on the screw.

L. Press the Start pushbutton momentarily to activate Step 11 of the sequence.

The PLC de-energizes SOL6 and the knob assembly cylinder retracts. The screw motor also turns off.


124

M. Press the Start pushbutton momentarily to activate Step 12 of the sequence.

Clamp cylinder 2 retracts indicating the end of the assembly process.

N. Press the Start pushbutton momentarily to activate Step 13 of the sequence.

The PLC signals the robot that the valve is assembled. The robot then moves over to the assembly, picks it up, and drops it in the part bin. The robot will then get a new spring/knob assembly, place it in the assembly station, and move to a wait position.

21. Click the Monitor button to go offl ine from the processor. 22. Use the PLC programming software to place the PLC into Stop mode. 23. Print out a copy of the ladder logic program and place it in your portfolio. It

will be used in your assessment. 24. Perform the following substeps to shut down the 87-MS5 Servo Robotic

Assembly station.




D. Turn the 87-MS5’s Main Power switch to Off.




125


1. Servo robotic assembly stations typically combine several different assembly modules and one or more _____.

2. One servo robotic assembly station sequence is a combination of a spool insertion module, screw feed module, and a __________ module.

3. Selecting automatic mode causes the PLC to disable _____ functions.

4. In automatic mode, the servo robotic assembly station performs a sequence of operation every cycle under the control of a _____.

5. In _______ mode, the user is able to move the machine’s actuators on an as needed basis.

Documents

SERVO ROBOTIC ASSEMBLY - Edl · PDF file · 2017-01-02Computer with Windows XP Operating System Amatrol or School Supplied ... A servo robotic assembly system performs a sequence