2-01200-PO-M-070 REV F PLC Programming Standard for ControlLogix_revF

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TITLE: PLC Programming standard

for ControlLogix

DOCUMENT NUMBER:

2-01200-PO-M-070

Page 2 of 32

Rev 2

1. DOCUMENT OBJETIVE

The purpose of this document is to define a standard approach to structure, organize and develop

automation applications based on Allen Bradley RSLOGIX5000 Programmable Logic Controller (PLC)

type Control Logix for TENARIS TAMSA.

2. PLC PROGRAMMING STANDARDS

2.1 General Principles.

The necessary software to command all mechanical equipment must be developed in

accordance to the sequential programming principle.

Sequential programming is based on the use of state machines (from now on sequencers).

Each sequencer is therefore based on a series of states and transitions that define the change

from one state to another.

The execution sequence provides the possibility of cycle interruptions due to emergency

conditions or due to operating mode changes. In all cases the program organization should be

respected.

Main objective of sequencer technique is to reduce startup times and maintenance intervention

time by means of quicker diagnosis while always assuring personnel and machines safety.

It is important to correctly define the different required sequencers during the project phase.

The best practice used to define a new sequencer is to control all mechanical elements related to

only one piece transformation at the same time. The respect of this concept is very important to

define clear and simple sequencers, easy to understand, diagnose and maintain.

2.2 Safety.

The sequencer structure assures that signals emitted from field sensors (i.e. Proximity switches,

fotocells, etc.) are detected by the logic only when they are expected during the automatic or

semiautomatic machine cycle.

This avoids that accidental sensors triggering could cause a drive to engage.


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3. PLANT DIVISION AND OPERATING MODES

3.1 Zone and Area

A zone of a plant is defined in terms of emergency requirements. A group of machines and

equipment that shares a common emergency defines a zone of a plant. A zone may have one or

more sequencers involved.

When an emergency stop is activated, all sequencers of the zone must go to the final step of the

sequence.

In this step, no output will be enabled by software nor hardware. Output modules power supply

will be cut off.

One or more related zones define an Area. Each area will be organized in accordance tooperating needs and modes (manual, automatic, semiautomatic).

3.2 Modes of Operation.

There are 3 operation modes defined: manual, semiautomatic (only when required) and

automatic.

Therefore there is normally a 3-mode selector in each main pulpit zone (or HMI equivalent) that

controls all related sequencers (and thus drives, valves, etc) of the zone.

Defining each zone as an Island enables to operate one zone in manual mode while the rest of

the zones continue to operate in automatic.

The automatic mode typically includes the possibility of having an automatic cycle stop in order

to concent the stoppage of the sequence in a predefined step. Once removed this command the

sequencer continues with its normal operation.

3.2.1 Automatic.

In automatic mode the plant works without the operators intervention, which in fact only

monitors process information. Therefore, suitable instruments must be installed for the

process variables to be controlled.

Once selected the automatic mode, a light button begins to blink. A confirmation from theoperator is required. If all sequencer first piece conditions (see chapter 6) are present,

the mode is confirmed and the light remains ON.

The transition from automatic to semiautomatic mode generally does not interrupt the

automatic operating cycle under excecusion. All movements will stop once the cycle is

completed and the sequencer will wait until the operator hits the one cycle button.

Transitions from automatic to manual mode interrupt the cycle that is being executed.


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For complex machinery (for example a rolling mill) there might be no advantage in

interrupting an automatic cycle and it could also be risky. For urgent situations the

emergency stop is recomended.

On the other hand, for simple machines it can be helpful in some cases to change tomanual mode in the middle of a cycle. Normally it is easy to recover the automatic mode

without losing the piece under process. The use of the emergency stop could be

considered a too drastic remedy.

The main objective is to keep operation in automatic mode as much as possible.

Many machines can have an automatic stop cycle selector in order to stop the cycle

without changing the operation mode. This is normally used to update the machine

presets, to conduct an inspection routine, etc.

It is not necessary for all the sequencers of a zone to react to the automatic stop

selector. Many times its enough to stop those sequences that are related to preset or

inspection operations.

If, for example, we have a loading conveyor and a walking-beam being part of the same

zone, it could be preferable to stop only the conveyor while maintaining the walking beam

active and once its empty update the new presets.

3.2.2 Semiautomatic.

The semiautomatic operating mode is an aid to the operator in order to handle situationsin which it is not possible to work in automatic mode.

This mode is generally used in the following cases:

To simulate a complete cycle without the presence of a piece. The operator shouldset the semiautomatic mode and press the defined command button.

In this way if the cycle ends properly, the operator can verify that there are no electrical ormechanical problems.

To force a complete cycle of one or more sequencers in cascade with/without atube on line. For example, a complete automatic cycle simulating one or morerolling mill stands, running a tube back and forth under the NDT equipment(nondestructive control), etc.

In this case, the operator, always in semiautomatic mode, has a button with a step bystep function. At the end of a cycle phase, the button light will begin to flash to request

authorization for the next phase.

3.2.3 Manual.

In this operating mode, the operator can directly independtly move different mechanical

equipment.

PLC logic should restrict the possibility of making movements that could harm people or

equipment.


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Manual mode can be used from main pulpit in the control room ( normally used by

operators ) or from an eventual local control pulpit ( normally used by maintenance

people).

Operation from either main or local pulpits must have all the required locks in place toprevent eventual mechanical interference that could damage in place machines or

people.

4. PULPIT. GENERAL CONDITIONS.

4.1 Traditional Pulpit (Control Desk).

Traditional pulpits or control desks have been gradually replaced by programmable Touch

Panels. On these panel screens, the operator has selectors, buttons and all necessary

information to fully take control of a zone and its machines. However, due to security issues,

elements such as emergency stops are physically wired to PLC and power centers.

The following physical elements should be present in each area:

The emergency stop button (red) with mechanical interlocking and with middle turningaround to unlock. It must be connected to the NC (normally closed) contact.

Also depending on machines and processes

A joystick for easier Manual jogging (to move pieces, regulations, etc) in forward,

reverse, up and down.

Other physical elements whose functionality is frequently used or is strictly required

for the operation.

4.2 Touch Panel.

The primary goal of a Touch Panel is to provide the operator the necessary tools to fully operate

the involved machines. The operator should take control of the process by selecting the operating

modes and executing manual commands when necessary.

Touch Panel views must clearly show the operator all movement status indicators, drives

conditions, critical variables values of all related machines.

See document: Tenaris Touch Panel Guide Lines TEP.


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5. PROGRAMMING LAYOUT

For PLC programming is necessary in order to save the files program so that always met the following

criteria, see Figure 5-1:

Fig. 5-1 Program Structure of a PLC Program

5.1 Fault Program

This file is called Fault Program, which is assigned by default to the following address: PLC name \

ControllerFault Handler\ FAULTS, and this is generated through the Basic Standard Module called

MajorFaultRecordused to obtain Type and Code of the PLC fault. The following report show theprogramming standard for the default file:

Fig. 5-2 Basic Standard Module for management of Major Fault


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5.2 P01 Inpu ts.

This program copies all the data maps of the inputs elements (for example; elements of a Device

Net Network).

5.3 P02 Main Prog ram.

This program contains all general logic subroutines that deal directly with machine operation or

the handling of a zone.

F02_Main

F03_Services (Traditional Logic with basic standard modules)

F04_Safety

F05_Interruptions

F06_Tracking

F07_Level2 F08_Events

F12_ASCII_Modules (Logic with basic standard modules)

F13_PID

F15_HMI_Interfase

F16_InOut_Analogical

F18_Initialization

F19_Diagnosis

F20_Alarms

5.3.1 F02_Main_Routine.

This file controls the order in which the rest of the files will be executed ( i.e. Services,

power up initialization, etc ). Also includes the necessary logic to support

automatic/semiautomatic or manual modes, emergency stops, sequecer reset, etc.

An example of programming of a main file:

Fig. 5-3 Main Program structure


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5.3.2 F03_Services

Logic related to General services (i.e. oleo dynamic central, fan extractors, instruments blowers,

etc.) may be programmed with a traditional logic (not sequencers) and basic standard modules,

depending on the problem complexity.

5.3.3 F04_Safety

All logic related to the security status of input and output devices by a possible failure of the

modules that are controlled in the PLC must be present in this file.

5.3.4 F05_Interruptions

Everything related to process delays and interruptions must be programmed in this file.

5.3.5 F06_Tracking

All pieces tracking logic must be programmed in this file including interfaces to/from level 2 PCs.

5.3.6 F07_Level_2

All the information that is exchanged between the PLC and the PC shall be programmed in this

file for all data that are necessary to control.

5.3.7 F08_Events

This file includes all necessary logic to provide level 2 PCs the define events to be logged.

5.3.8 F12_ASCII_Modules

In this file should be programmed everything related to an ASCII card usage.

5.3.9 F13_PID

Everything related to PIDs control logic required by a process shall be programmed in this file.

Note: The PID control logic should be programmed in a periodic task while all auxiliar logic into

task continues F13_PID routine.

5.3.10 F15_HMI_Interfase

Interfaces for Level 1.5, as such the HMI ( Touch Panels ) shall be programmed in this file.

5.3.11 F16_InOut_Analogical

Analog inputs and outputs cards shall be programmed in this file.

5.3.12 F18_Initialization

In this file shall be programmed all devices or drives that requires an initialization.


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5.3.13 F19_Diagnosis

General diagnosis logic for local and remote modules must be programmed in this file.

5.3.14 F20_Alarms

All the generated alarms shall be copied into this file to provide level 2 PCs an organized

interface to access.

5.4 P03 Outp uts.

This program copies all the outputs elements data maps (i.e.: elements of a Device Net Network).

5.5 S01 Sequencer (32 or 64 states) .

Each sequencer used should appear consecutively in these program folders, both machine and/or control

area sequencers (32 or 64 states as required)

The distribution of the PLC Program can be seen in the following PDF annexed document ( i.e. Handling

& Cabezal y Tina de Temple de TTR3 program)

See reference Document (1) HCT_TTR3.pdf.


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6. LOGICAL SEQUENCER STRUCTURE.

The sequencer structure assures that all signals coming from field sensors (inductive, limit switches, ultrasonic,etc.) are considered only in the right sequence step for both automatic and semiautomatic operation modes.

The logical structure of a sequencer guarantees that all sequencers of a zone will check all required startingconditions making easier and safer the coordination of many interrelated sequencers.

This enables also huge diagnostic efficiency for maintenance and operation people.

As a general guideline, the use of 32 states sequencers should be considered for most applications and only

when required (for complex processes) sequencers of 64 states could apply.

Typically, the first six ( 1-6 ) and last four steps (29-32) are used by sequencers for predefinied standard

functionality like power up, first piece conditions, manual mode, coordinated stop, emergency, etc.

During the movement states of the sequencer (7 to 28) the transitions must be designed andimplemented according to the application needs of movement. It is important to established that

there should be considered to chose for each different movement or position each 5 states, it meansto use steps 7,12,17,22,27.

Only with Piece Presence signal ON a sequencer can evolve and only after checking all predefined

interlock conditions will be be launched.

The Figure 6-1 represents the sequencer structure, steps and transitions as basic example.

Figure 6-1 Logical structure in sequencer


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6.1 STATE 1 (Sequencer Start)

This is the initial state for each sequencer:

6.1.1 Transition to state 1.

The sequencer moves to this state each time that:

The PLC is Powered Up

When operating mode change from Manual mode to automatic or semiautomatic modes.

Each time is pressed the reset button after a sequence stop or an emergency stop.

6.1.2 Transition from state 1 to state 2 (First piece conditions).

The first piece conditions are all those required to initiate an automatic or

semiautomatic operation of a zone.

This check up - if OK - maximizes the probability that the first piece will correctly end all

sequences trought a zone.

Examples of first piece conditions are: home position verification, motor protections and

drives OK, oleo dynamic services ready, air preassure OK, etc.

These conditions are always verified when coming back from manual to automatic or

semiautomatic modes.

6.2 STATE 2 (Piece Presence conditions).

These conditions are normally different when automatic or semiautomatic mode is

selected.

As previously mentioned, semiautomatic mode is normally used to check equipment, for

example:

Run a complete cycle of a sequencer without a the presence of piece

Run a complete cycle of many sequencers in cascade having or not a tube

on line but making a step by step operation.

In automatic mode the verification of the presence of piece conditions are absolutely

required to transition to state 3.


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6.2.1 Transition from state 2 to state 3 (piece presence conditions ).

These conditions enable the execution of a new cycle.

In automatic mode this condition could come from:

A preceding sequencer

A sensor that physically detects the piece presence.

Other conditions such as: pipes buffer full sensor, by pass selector, etc.

It is important to remember that in addition to the physical piece presence there are

many times a logical piece flags that indicates when a piece has all required

operations done.

In semiautomatic mode these conditions could be overrided by the cycle start button.

Additionally, must be verif ied that the automatic stop selector is OFF before a

sequencer can initiate a cycle.

It is also important to remark that all sequencers related to the one under analysis should

check the same automatic stop selector when appropriate.

Note: These conditions are evaluated in the transition 02 to 03 in series with the sensor of

Piece Presence (i.e. a kick out). If these conditions were evaluated on the 03-04

transition conditions, there could be a sequencer stop transition due to missing enabling

conditions.

6.3 STATE 3 (Enabling Conditions).

In this state all sequencer external enabling conditions are verified.

Normally, in this step all downstream sequencers states are verified to check if they are

ready to receive a piece during continuous operation.

6.3.1 Transition from state 3 to state 4 (enabling conditions).

Enabling conditions are those that arise from the state machine that is immediately after

the one under analysis.

For example, a roller conveyor enabling condition could be an acknowledge that the

downstream kick off sequencer is on state 2, ready to receive the piece.

6.4 STATE 4 (Tracking conditions).

Sequencers will normally check in this step the presence of the tracking conditions ( only

when tracking is required ) before launching a new cycle.

If there is no tracking confirmation, the sequencer will stop.


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6.4.1 Transition from state 4 to state 6 (tracking conditions).

These conditions do not depend on the sequencer itself but normally come from:

Level 2 systems : Confirms that all piece tracking attributes are OK

Other PLC sequences.

6.5 STATE 6 (Starting Conditions).

In this state the so called starting conditions are controlled before transitioning to the

next step.

In other words, these represent the necessary conditions to start the machine movement

like: permanent conditions of communications, electrical, services, of the sequence, etc.

6.5.1 Transition from state 6 to state 7 (starting conditions).

The starting conditions are normally a subset of the first piece conditions and when

present the sequencer should have the best chance to finish the new cycle without

interruptions.

It is the last opportunity to check general communications and services status before

making any physical movement.

These conditions are controlled in each squencer cycle since there is always the

possibility that during the machine process something could have changed.

These are the conditions related to sequencer itself, such as communications, electrical,

services or sequence permanent conditions.

6.6 STATES FROM 7 TO 28 (Machine motion states).

Machine movements normally begin from this step on.

Sequencers proceed to control the process cycle by means of a subset of states where

each one of them correspond to a logical precise action.

STATE 7

Is the first step of the sequencer where begins movement of machine, to state 28.

The movement of the mechanical machinery begins in this state.

STATE 28

This Is the last available state for normal the machine cycle when in automatic mode.

After finishing a cycle the sequencer should transition to step 2.


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6.6.1 Transitions between state 7 to state 28 (Machine movement).

It is advisable beginning from state 7 onwards (see Chap. 6.6) leaving an open number

for 5 states (7, 12, 17, 22, and 27) so that we can identify changes in the sequence of

movement.

STATE 30 (Manual mode).

This state is activated when the operating mode selector is in MANUAL mode.

Normally the selection of Manual mode immediately interrupts sequencer cycle

generating a transitionin to step 30.

6.6.2 Transition to state 30 (Manual mode).

The unique condition for the transition to Manual state is when activated the operating

mode MANUAL.

6.7 STATE 31 (Hold).

This state is created to be used when a special situation requires having a HOLD of the

sequence, without the timeout control.

The necessity of these conditions has to be defined for each application, considering the

specific requirements.

6.7.1 Transition to state 31 (hold conditions).

During the sequencer movement states (7 to 28), the transitions to/from to the hold step

can be designed and implemented according to the application needs.

6.8 STATE 29 (Stop).

This state is used when a fail condition appears and the sequence must be stopped.

6.8.1 Transition to state 29 (stop).

The stop conditions that lead the sequencer into state 29 might be:

Emergency conditions re-established.

Sequencer step time out.

Lost of permanent conditions.

To get out from the state 29 the RESET button has to be pushed. Depending of

the operating mode, the sequencer will go to the states 1 (if Automatic Mode is

selected) or 30 (If Manual Mode is present).


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6.9 STATE 32 (Emergency Stop).

Sequencers go to state 32 every time the operator activates an emergency stop no

matter what state squencers are currently in.

Technical standards recommend using an emergency stop whenever there are

dangerous conditions for people or machinery. Wired electromechanical components

should be used and hardware signals should be transmitted to the PLC in order to disable

all outputs.

The NC red emergency push button must cause:

The emergency relay disconnect,

Energize the red light that is part of the emergency button,

Power OFF both electrical drives and the PLC ouput lines while maintainingpower supply ON for PLC inputs.

Auxiliary contact of the Emergency button should be cabled to PLC inputs to

send involved sequencers to step 32 and for diagnosis purposes.

The return to normal conditions (non-emergency) can be made only with the unlocking of

Emergency Stop mushroom PB.

Once the emergency conditions are not present anymore, the sequencer is automatically

driven to the fail stop (Step 29), in order to wait for the Reset confirmation from the

operator.

Note: the Reset push button impacts on a determined emergency zone.

6.9.1 Transition to state 32 (Emergency Stop).

The emergency stop generates transition to state 32 (even for 64 states sequencers) regardless

any current state that the machine is at any time.

The sequencer logical structure, we can be seen the annexed PDF document

Secuenciador_KICK_IN.pdf

6.10 Sub-Sequencers.

In some complex machines it may be required that in certain sequencer states, a series of

parallel operations must be done. In such cases a sub-sequencer may be used.

The main sequencer controls all related sub-sequencers so it is not necessary to implement all

control conditions described before applicable only to main sequencers.


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7. PROGRAM FUNCTIONAL BLOCKS ORGANIZATION.

Sequencer functional blocks organization is described in the next figure 7-1.

Figure 7-1 Organization of program functional blocks

7.1 Sequencer Standard implementation (32 or 64 states).

Sequencers are managed as programs called Sxx_name, where xx is the number of the

sequencer.

Sequencer No.1, for example, is the program: S01_ "name_of_sequencer_01".

Sequencer No.2 is the program: S02_ "name_of_sequencer_02" and so on up to S32 that is the

maximum number for programs to be scheduled in the continue task).

In each sequencer program, we should find everything related to the process under control. For

example:

Where:

Program Tags: Include all local variables declaration

Subroutine Jum s

Control Out uts Basic Standard Modules

Communication Permament Conditions

Se uence Permisives

Position Aux. Fla s

Se uencer Transitions

Logical Machine Sequence

Electrical Permament Conditions

Services Permament Conditions

Field Outputs


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F01_Main: Contains main control logic of the sequencer and their transitions.

F02_Auxiliares: Contains all combinational auxiliary logic used by the sequencer (starting

conditions, first piece conditions, etc )

F03_Salidas: Includes all field outputs management

F04_ Diagnosis: Includes all necessary logic for diagnosis.

F05_ Touch Panel: Includes all necessary logic to integrate a sequencer with the corresponding

touch panel (indicators, virtual buttons, etc.).

In the annexed PDF ( Secuenciador_KICK_IN enable in TTR3 ) we can see a real example for

sequencers logic organization.

7.2 Logic scan (Performance).

Internal coils related to sequencer step word must be always used in logic networks afterconvertion has occurred in order to avoid losing a scan to detect a sequencer step change.

8. ORGANIZATION FOR THE DIAGNOSIS.

The organization for general diagnosis file is shown in figure 8-1.

Figura 8-1 Organization of the diagnosis

8.1 General diagnosis Standard implementation

General diagnosis is part of a Subrutine (P02_Prog_Principal\F19_Diagnosis) where all alarm

conditions are programmed.

All specific alarms must be programmed respecting the following order: PLC local and remote

modules, Services (oleo dynamic central, fan extractors, instruments blowers, etc.) and finally

direct alarms.

Inside P02_Prog_Principal\F19_Diagnosis routine we should see:

The automation system logic alarm columns

The service alarm logic alarm column,

The direct alarm logic column

A General diagnosis Subrutine example can be seen in the annexed PDF document

HCT_TTR3.pdf.

PLC Automation System Alarms

Services Alarms

Direct Alarms


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The proposed organization for Sequential Diagnostic file is as follows:

Figure 8-2 Organization of the sequential diagnostic file

8.2 Sequencer diagnosis.Standard implementation

Sequential diagnosis forms part of a Subrutine (Sxx_name_of_sequencer\F02_Diagnosis) where

all alarm and warning conditions related to a given sequencer should be programmed.

Inside the routine Sxx_name_of_sequencer \F02_Diagnosis we should find :

States generation (1, 30, 32 or 64 states if the sequence requires).

Rungs for logic alarm.

Rungs for logic warnings.

Sequencer DRUM or actual state convertion.

This conversion has the following functionality:

Set up only one of the 32 bits ( or 64 when a 64 states sequencer is used)

corresponding to current sequencer step.

Actualize in the 32-bit internal register the current step number.

The only value returned by le logic is the internal sequencer step value.

A sequencer diagnostic Subroutine example can be seen in the annexed PDF documentSecuenciador_KICK_IN.pdf.

Sequencer States Generation (1, 30, 32)

Sequence Cycle Time Calculations

Sequencer DRUM

Sequencer Warnings and Alarms.


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9. ALARMS

Wthin the F19 Routine (P02_Prog_Principal\F19_Diagnosis) all General alarms must be programmed while

logic for all Sequenceralarms and warning conditions must be present in F02_Diagnosis Routine.

The F20_Alarms Routine must include the necessary interface with Level 2 logic to support both general andsequencer alarms.

9.1 Alarms.

The alarm bits are set whenever an alarm is present and reseted when disappears. Arrays of

alarm bits are red by Level 2 systems that are connected to PLCs by means of an automation

network like Ethernet or ControlNet. PC systems provide a better way to manage and display

complex information to the operators.

The Level 2 alarm module must:

Show all primary alarms that really occurred. This means that in many cases some

filtering must be done to distinguish the originary fault cause (i.e. a power down that

can trigger many other not real alarms, a communication problem, etc).

Give precise explanations about the failure.

Generic descriptors such as lack of transition from step x to step y or lack of first

piece conditions are not acceptable without further details.

Operators should in any case clearly recognize the origin of the fault to reduce

intervention

time.

The alarms are mainly divided into two groups:

Sequencer alarms are normally generated evaluating incoming events (signals) in a

given sequencer step.

Direct alarms can be activated in any squencer step

9.1.1 Sequencer filtered alarms.

They can be subdivided in:

First piece conditions ( when sequencer remains in step 1 )

Enabling conditions ( when sequencer remains in step 3 ) Tracking conditions ( when sequencer remains in step 4 )

Starting conditions ( when sequencer remains in step 6 )

Sequence Alarms ( from step 7 on )

Emergency ( when sequencer remains in step 32 )


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9.1.1.1 First Piece Conditions.

Whenever a sequencer is in step 1, a blinking light on the pulpit indicates the

operator to press the automatic start cycle button to become operative.

Once pressed, if the first piece conditions are OK, the sequencer will go to step 2

and the light will turn ON. Otherwise the sequencer wil remain in step 1 with the

light blinking.

Normally the first piece conditions are more than one and only the lacking

conditions should be displayed on the Level 2 PC monitor.

In other words the first piece conditions are programmed individually so that when

one of them is absent it is possible to detect it precisely.

The event used to check the fist piece conditions is the automatic start cycle

button pressed by the operator.

9.1.1.2 Enabling Conditions

As stated previously, a sequencer transition from step 3 to step 4 depends on the

status of other related sequencers that should enable it.

At this point it is important to take into account:

Include a clear explanation of the machine involved when the signal notenabled is displayed to concent the operator actuate on the correct

machine that blocks the cycle.

Timely filtering of the alarms to prevent incorrect alarms.

So it is important to evaluate in each case how to correctly implement the

enabling conditions to avoid giving misleading information to the operator.

9.1.1.3 Piece Tracking conditions

Once in step 4 - and only when piece tracking is supported -, the piece tracking

conditions will be evaluated before enabling transition to the next step.

9.1.1.4 Starting conditions

Whenever a sequencer does not transition from step 6 to step 7, starting condition

alarms will be generated and displayed on the PC monitor.

Normally the staring conditions are more than one. Only the lacking conditions

should be displayed.

In other words the starting conditions are programmed individually so that when

one of them is absent it is possible to detect it precisely.


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9.1.1.5 Sequence alarms.

The sequence alarms are associated to steps 7 to 28.

These alarms are generated by delays or failures of field sensors expected for

proper sequencer transitions.

The steps 7 to 28 do not have a predefined function, so it is appropriate to use all

needed steps to diagnose as better as possible the different field elements.

It is important to check all individual sensors involved whenever a sequence alarm

is triggered.

9.1.1.6 Emergency.

All emergency actions will be triggered whenever the operator presses the

emergency button, which normally will send involved sequencers to step 32 ( also

valid for 64 states sequencers )

9.1.1.7Automation Alarm system.

Are alarms that control the functioning of the automation system.

These alarms are for: low batteries, overall rack failure, (Minor Faults, are

monitoring through basic standard modules called MinorFaultCheck) of some

major flaw present like the watch dog (Major Faults, are monitoring through basic

standard modules called MajorFaultCheck), and finally a failure of individual racks.

9.1.1.8 Services Indication

This foresees the possibility of programming ad hoc logic in the PLC to generate

an event to be logged in the Level 2 Event module.

For example: manual mode selection, cycles repetition, etc.

They are not to be considered alarms but events that should help to understand/log

particular operating conditions.

9.1.2 Direct alarms

There are cases in which it is not possible to relate an alarm condition to a

sequencer step.

They can be subdivided into:

Pre-alarms to indicate to the operators that some action must be taken to

prevent imminent problems.

Alarms to indicate a fault situation that requires direct action to be solved.

Some examples of direct alarms could be:

Burnt out fuses.


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Thermal tripping

No voltage.

Communication failure (Controlnet and Devicenet usually used)

Hazardous service

PLC in emergency Etc.

A particular case of direct alarms are the automation equipment alarms such as

low batteries, overall rack failure, etc,

Minor Faults, are monitored through basic std modules called MinorFaultCheck and

Major Faults are monitored through basic std modules called MajorFaultCheck.

Generally speaking, Direct alarms are difficult to manage since there is no

sequencer step that can filter them. Once a direct alarm is generated it is displayed

on the Level 2 monitor.

As an example of alarm filtering, downstream auxiliary breaker contactors shouldbe in series with principal power contactor to avoid having spurious information

and only recognize the first failure.

Whenever possible is recommended to monitor direct alarms such as:

Auxiliary breaker Contactors,

Thermal relay auxiliary Contactors,

Fluid levels, thermostats, directly controlled presostats, etc.

All necessary precautions must be taken to prevent generating misleading

information for the operators.

9.1.3 Programming alarms in the PLC.

A Direct alarm is 1 whenever the cause that has triggered it remains.

A Sequence alarm is 1 only when the cause in that step remains.

Sequence alarms are filtered from a unique timer (one for each sequencer) that is seted

depending on the step the sequencer is at any moment.

Each sequence of 32 (or 64) steps has a defined alarm structure: see Figure 9-1:

Alarms (Word_00; tipo de dato DINT) Warnings (Word_01; tipo de dato DINT)

Drive Alarms (Word_02; tipo de dato DINT)

Alarms Adjacent (Word_03; tipo de dato DINT )


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Figura 9-1 Alarms structure of a sequencer

10. DOCUMENTATION

10.1 Genaral Documentation

Documentation to be submitted by the supplier will be in Spanish or English depending on the

official language of the mill and it must also have the following PLC software project information:

Sequencer Flowchart in Visio format (alternatively Word) and supplied in hardcopies and

CD/DVDs.

Ladder Logic: Each contact, coil, input and output must be clearly commented as well as the

functional description of the complex blocks.

Input/Output Diagrams in Autocad format supplied in hardcopies and CD/DVDs.

Functional specification for maintenance people.

10.2 Software Development

Software development must be done using RS Logix 5000 Industrial Programming Software version17.00.00 or more.

10.3 Standard Nomenclature for the symbol names (Auxiliary Text).

The nomenclature to be used inside the sequencers must be:

The process state bits are indicated symbolically with the following notation:

Pxx

In which Pxx indicates the step number xx (i.e. P07 represents the state 07 of a given

sequencer).


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Remember that the sequence number is given for each program set within the "continue task"

(As example S01_ "nombre_del_secuenciador")

The status word will be scheduled with the following notation

PASO

The sequencer process bits when not under operation are symbolically represented with

the following inscription:

PxxNOP

Where Pxx represents the step xx of a sequencer and NOP means not under operation or not

used (For example P08NOP represents a sequencer in a non operative step) These steps are a

available for future use.

The timers required to filter sequencer alarms must have following notation:

AuxiliarTimer [xx]

Where AuxiliarTimer means General auxiliary Timer and xx is the register number. For

example, AuxiliarTimer [10] is the timer used to filter Step 7 sequence alarm. The timers array

for each sequencer should have a length of 20 registers, assigning the first 10 registers to

auxiliary sequencer logic and the other to alarm filtering.

The counters for logical development of the sequencers will be marked with the following

notation:

AuxiliarCounter [xx]

Where AuxiliarCounter means General auxiliary counter and xx is the register number

corresponding to an specific counter. For example, AuxiliarCounter [0] could represent the count

of the cycles performed by a given machine. The counters array for eachsequencer should have

a length of 10 records.

The Emergency bits, including hardware and software sequencers will be indicated with

the following notation:

EMERGMode

Where EMERGMode means Hardware or software generated Emergency, this bit is responsible

for forcing the emergency state in the sequencer.

Sequencer alarm bits are represented in the alarm word with the following inscription:

Alarm.xx (DINT)

Where Alarm indicates the sequencer alarm Word , while xx indicates the assigned bit to

that alarm in the sequencer (as example Alarm.00 represents the first alarm of the sequence).


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Sequencer warning bits are represented in the warning word with the following inscription:

Warning.xx (DINT)

Where Warning indicates the sequencer warning word, while xx indicates the assigned bit tothat warning in the sequencer (as example Warning.00 represents the first warning of the

sequence).

The alarm bits linked to the PLC will be symbolically represented with the following

inscription:

AlarmGEN [uu].vv

Where AlarmGEN, which indicates the general table alarms of the PLC (programmable logic

controller), uu the initial register of the general alarm table and vv is the assigned bit to the

particular alarm (as example AlarmGEN [00].00 represents the general alarm, first in the PLC).


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10.2 Sequencers Graphic Representation

The graphic representation for a sequence is a Grafcet type, detailing the number of the

sequencer, the description of the function performed, the way the field elements act (NC or NO)

indication of command that is made.

We can see in the example the symbology used in the flowcharts. Next to each flowchart, there is

a description of the first piece , starting conditions, etc.

1. Normally open contact:

2. - Normally close contact:

3. Positive transitional contact:

4. - Negative transitional contact:


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5. - AND of 2 contacts:

6. - OR of 2 contacts:

7. Step sequencer:

8. - Temporized:


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In the following diagram is represented a Kick-in station sequencer, which loads piece to Tina

Temple

Figure 10-1 Example Sequencer


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Figure 10-2 Example Sequencer


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11. SUMMARY OF GENERAL RULES

The program distribution is a follow:

Major Faults Program (Controller nombre de PLC\Controller Fault Handler\FALLS).

P01 Inputs Program.P02 Main Program. (Including the following routines)

F02_MainRoutine

F03_Services (logical traditional with basic modules)

F04_Safety

F05_Interruptions

F06_Tracking

F07_Level_2 F08_Events

F12_ASCII_Modules (with pre-defined basic modules)

F13_PID

F15_HMI_Interface

F16_InOut_Analogical

F18_Initialization

F19_Diagnosis

F20_Alarms

P03 Outputs Program.S01 Sequencer #01 Program.

F01 Main (Auxiliar Logic Transitions, inputs and outputs of the sequencer control)

F02 Diagnosis (Sequencer Diagnostic)F03 Touch Panel (sends to control interface)

Snn Sequencer n-esimo program.F01 Main (Auxiliar Logic Transitions, inputs and outputs of the sequencer control)F02 Diagnosis (Sequencer Diagnostic)F03 Touch Panel (sends to control interface)

The word to see the sequencer state is called: PASO

The support bit for the sequencers is called: PasoSecuenciador(word per sequencer)

The word alarm to see the sequencer state is designed as: Alarm (DINT)

The word warning to see the sequencer state is designed as: Warning (DINT)

The auxiliary timers for logical sequence and filtered alarms is designed as: AuxiliarTimer(Length ArrayTIMER [20] registers)

The Length Array Level 2 Alarms is: AlarmL2 (Length array AlarmL2 [500])

The auxiliary counters for logical sequence is designed as: AuxiliarCounter(Length Array Counter [10]registers)

The controls for the development of alarm logic are described in the document (**).


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12. ANNEX

Document of reference (1): Tenaris Touch Panel Guide Lines TEP.

Document of reference (2): HCT_TTR3.pdf.

Document of reference (3) - Secuenciador_KICK_IN.pdf

13. GLOSARY

Level 1: PLC and logic responsible for controlling the machine-process and reporting the status to the upperlevels (Level 1.5 and level 2).

Level 1.5: Human machine interface (HMI) is used to command the machine- process and provides theoperator the necessary status information.

Level 2: PC based automation systems that control machine presets, display process curves and alarms,manage machine stoppages, generate management reports, etc.

Tracking: Coordinated set of techniques (vision systems, sensors, level 1 & level 2 software) necessary totrack each tube on the plant.

Touch Panel/HMI: Human Machine Interface designed for the operator which functionalities include not onlythe machine control (i.e. command buttons, operation mode selectors, etc) but also machine diagnostics,sequencer status, alarms, mimics, among other applications for maintenance supervisors. This is considered

within the Level 1.5 Automation Classification.

Documents

2-01200-PO-M-070 REV F PLC Programming Standard for ControlLogix_revF