Top Ten Siemens S7 Tips and Tricks

Navigating the world of automation

2011 Automation Summit Orlando, FL


Navigating the world of automation Copyright © Siemens Industry, Inc. 2011. All rights reserved.

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2011 Automation Summit

Title: Top Ten S7 Tips and Tricks

Track: NAPR

Topic: S7 PLCs

Presenter: Nick Shea

Company: DMC


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DMC Company Profile

Established in 1996, based in Chicago, IL Service Companies Nationally & Globally Siemens Solution Partner

Global Reach: CanadaChinaGeorgiaCzech Rep.RussiaPhilippinesMexicoIndia


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Bio

Nick Shea

Senior Project Engineer at DMC

Engineering Physics (University of Kansas)

With DMC since 2006


Top Ten S7 Tips and Tricks

You already know the fundamentals of S7 PLC programming…

And the mistakes to avoid (thanks, Tim)

Now, how do you develop, commission and troubleshoot most efficiently?

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If you are an…

External Developer:

How do you work most efficiently to provide the highest value for your customer while increasing project profitability?


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If you are an…

Internal Programmer:

How do you reduce start-up time for new equipment and decrease production downtime while making modifications or troubleshooting controls problems?


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Now… take your development to the next Level!


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Tips and Tricks for:

1.Rapid Diagnostics / Troubleshooting

2.Rapid Development

3.Advanced Tools


Modular, Object-Oriented Architecture with FBs and UDTs

#1



Best Practices for Controls Design – Generally Accepted

•Consistent Design and Documentation• Mechanical Design• Electrical Schematics• P&IDs• Software



Best Practices for Controls Design… also includes:

•PLC and HMI Projects•Naming conventions•Hardware architecture

•Modular Software Architecture•Function Blocks•UDTs



System Architecture



Program Architecture(similar to system architecture!)



Example of High-Level Function Block:



Example of Device Level Function Block utilizing UDTs:



Variables encapsulated by udtHMI_VFD_Control



Variables encapsulated by udtErrors_VFD



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Motor Command Function Block

Start

Stop

Speed SP

Engage Brake

Reset Error

Acceleration

Motor I/O Function Block

Start

Stop

Speed SP

Engage Brake

Reset Error

Acceleration

Outputs Inputs

One variable is used to pass multiple pieces of information

StartStopSpeed SPEngage BrakeReset ErrorAcceleration

Motor Command Function Block

CommandMotor I/O Function

Block

Command


Monitoring Instances of Function Blocks

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There are two PLC modes and they are toggled in the CPU Properties on the “Protection” tab: Process Mode and Test Mode.

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Default is Process mode.

Switch to Test Mode.

Download the hardware configuration.



This option is also shown in the Debug -> Operation dropdown menu from the Ladder Editor

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Right-click on the block and select “Monitor with Call-Up Path”

Process Mode Test Mode

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Note! As you probably expect, this does slow down the CPU cycle time so this should

only be used when necessary and always leave the final system with “Process Mode” checked.

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Report System Error

#3


Report System Error

Siemens Support Website

FAQ: How can you report S7 system errors in WinCC?

FAQ: How can you have system error messages from a SIMATIC S7-300 / 400 displayed in WinCC flexible?

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Report System Error

End Result:

No (0) programming required!

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Report System Error

10 easy steps: (website has screenshots and full instructions)

1. Create S7 and HMI stations. 2. Add languages. Set “English” as default 3. Open the "Report System Error..." dialog in hardware configuration.4. Activate the entries. Choose the OB blocks that will generate messages5. Transfer blocks to the CPU. Download the generated blocks to the CPU.6. Add a connection to the CPU from the WinCC flexible project (if needed)7. Configure alarm settings. Activate Simatic SFM in the alarm procedure.8. Configure alarm viewer to include “S7 Alarms”9. Activate the check boxes in CPU Messages from Simatic Manager10.Start WinCC flexible and enjoy your diagnostic messages!

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RAM Disk

#4


RAM Disk

• When compiling an S7 project, many small files are read and written.• RAM Disk is RAM that is used as a disk drive – via 3rd party software.• RAM Disk is orders of magnitude faster than other forms of storage media.• We’ve reduced >10 min compile times to <3 min.

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Auto-Generate Symbol Table

#5



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The S7 PLC symbol table allows copy/paste directly from a spreadsheet such as MS Excel.

•If possible, develop your IO list in a compatible format•Alternatively, build a tool to convert it to a compatible format•For example, thousands of IO can be added into the symbol list in a few minutes.



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Using Local Memory to Parse Data

#6



Split data types into smaller pieces without using ST or SCL.

1. Assign a variable to TEMP memory.

2. Move data into the TEMP memory variable.

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Split data types into smaller pieces without using ST or SCL.

3. Access the TEMP or Local memory using the “L” prefix.

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Network Node Activating, Deactivating, and Monitoring

#7



Dynamically activate and Deactivate Profibus and Profinet Nodes

Using “D_ACT_DP” SFC12

Examples: • Modular Machines• Alternate Machine Configurations

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Monitoring Ethernet Nodes using “RDSYSST” SFC51

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Safety Programming

#8


Safety Programming

• Leverage Siemens safety blocks

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Safety Programming

• Safety program can be really simple or really complicated depending on the application.

• Example of implementing simple E-Stop safety functionality:

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Safety Programming

• Always ON and OFF variables available inside “F_GLOBDB” datablock.

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Backup DB Data by Generating Source

#9



A simple yet common problem when programming a Siemens Simatic S7-300 PLC is losing the data already stored in the PLC after downloading an updated data block.

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In the normal case:

If you are simply adding items to the end of a flat data block (not adding items to a user-defined type (udt) within the data block, for example) then to retain the values of the data block follow these quick steps.

Go online with all of the blocks in Simatic Manager. Copy the online version of the data block whose values you would like to retain into your offline project.Add the items to end of the data block.Download - your values will be retained.

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A more complicated change to the data block such as adding items to a udt used with the data block requires extra steps. Even if you have first saved a copy of your online values prior to making the change, the values will be lost after you save the change. Therefore, follow these extra steps.

Follow steps 1 and 2 above.Open the datablock and Generate Source for the data block. File -> Generate Source. This will save a version of your data block; and the values in a file in the Sources folder.

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3. Make all changes that you need to the data block (not source code) then Save and Close the data block.

4. Open the Source file you created and compile it. This will set all values in the data block equal to the values you see in the Source file.

5. Download - your values have been retained.

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Keyboard Shortcuts

#10


Keyboard Shortcuts

Navigating / Searching

Cross Reference: Ctrl-Alt-Q

Find: Ctrl-F

Find Variables within a FC or FB: Ctrl-Shift-F (search forward)or

Ctrl-Shift-B (search backward)

Jump to Network: Ctrl-E

Reference Data Interface: Ctrl-R

Open an FC or FB: Ctrl-Alt-O

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Keyboard Shortcuts

Development Shortcuts

New Empty Rung / Network: Ctrl-R

Normally open contact: F2Normally closed contact: F3Coil: F7

Empty Box: Alt-F9

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Keyboard Shortcuts

Monitoring / Diagnostics / Other Shortcuts

Monitor: Ctrl-F7

Module Information: Ctrl-D

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Keyboard Shortcuts

Monitoring / Diagnostics / Other Shortcuts

Operating Mode: Ctrl-I

Download: Ctrl-L

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Summary


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Summary – Top Ten S7 Tips and Tricks

1. Modular, Object-Oriented Architecture with FBs and UDTs

2. Monitoring Instances of Function Blocks

3. Report System Error

4. RAM Disk

5. Auto-Generate Symbol Table

6. Network Node Activating, Deactivating, and Monitoring

7. Safety Programming Basics

8. Using Local Memory to Parse Data

9. Backup DB Data by Generating Source

10. Keyboard Shortcuts


Thank You

Nick [email protected]

www.dmcinfo.com

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Technology

Top Ten Siemens S7 Tips and Tricks