SFC in PCS7 basic questions

Hi,

I made a SFC for my plant. (see below for details). I have some basic questions which I could not find in a manual I hope you could help me.

How can I make sure that the sequence repeats over and over, should I just link the end to start?                                                                                                                                                                          How can I make a button that I want my sequence to start in wincc? (just link a wincctag to start?)
How can I make a button to finish the current batch and then end the sequence? (I think make side transition after the end which is false if I want to stop after batch is finished?)
How can I make a tag thats counts all the finished batches?
How can I make a button to stop everything immediately? (I think Work with side step and then condition stop button = true towards the end?)

Furthermore,
I have a level transmitter which is the most important input for my SFC, it has an analog input as an IB, could I just use a convert the byte to word block in order for the level transmitter to function?

Furthermore I have a valve which I only want to open for 0 seconds. (just a pulse open, and immediately close). If I add a timer and set it to 0 seconds that Q=1, will it still give this pulse to Q? or should I use miliseconds in order to make sure it really opens for a fraction of time?

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water valve pulper is opened
Level Transmitter AGpulper reaches 5300 L (or other specific level to be determined)
The water valve pulper is closed
AG pulperMotor start
AgstortbandMotor start
AgdwarsbandMotor start
AgdoseerbandMotor start
Level Transmitter AGpulper reaches 7600 L (Or other specific level to be determined)
AgstortbandMotor stop
AgdwarsbandMotor stop
AgdoseerbandMotor stop
Timer starts for 35 minutes (Or other specific time to be determined)
After 35 minutes
AGpulpValve1 opens
AgpulpValve2 opens
PulperPump starts
Level Transmitter AGpulper reaches 6800 L (Or other specific level to be determined)
The water valve pulper is open for 0 seconds
The water valve pulper is closed
Level Transmitter AGpulper reaches 5500 L (Or other specific level to be determined)
ValveAGpulperpump canalwater  is opened
Level Transmitter AGpulper reaches  2000 L (Or other specific level to be determined)
AG pulperMotor stop
ValveAGpulperpump canalwater  is closed
PulperPump stops
AGpulpValve1 closes
AgpulpValve2 closes
Batch count+1
The water valve pulper is opened
Etc. sequence is started again
--------------------------------------------------------------------------------------------------

By the way I see that I can make more action at the same time in one step in order to simplify my SFC. Some steps and transitions are blanco, but then the sequence would still move on right?

AGrS

Hi,

I made a SFC for my plant. (see below for details). I have some basic questions which I could not find in a manual I hope you could help me.

How can I make sure that the sequence repeats over and over, should I just link the end to start? 

You can set parameter: "Cont" to make a SFC go into Continues mode. See attachment for more info or make sure your start condition for the current sequencer is always active or you can make a jump in the last step with a "always true" bit and the transition from the last step to the END step must be an "always false". Then you can set the jump condition to every step you want and the sequence will repeat itself.      

                                                                                                                                                                    How can I make a button that I want my sequence to start in wincc? (just link a wincctag to start?)

Just create a OP_D (Classic library) or a OpDi01 (APL) and just use the corresponding inputs and outputs in your SFC. You can start the SFC by interconnecting "Out" of the OpDi01 block to the "START" command of the SFC (in automatic mode). Or you can already start the SFC, but make a transition after the "START" step, where you check if Out=1.

How can I make a button to finish the current batch and then end the sequence? (I think make side transition after the end which is false if I want to stop after batch is finished?)

There are numberous ways. The one thing I like to do (conform ISA standard) is to use ABORT, STOP commands. ABORT on the SFC input will initiate the ABORT sequence. In order to use this, you have to create a new sequencer which has a start condition: "ABORT = ABORTING". In there you can for example close all valves and motors immediately. After ABORTING, the SFC is in state ABORT and you have to restart/reset the SFC in order to start it again. Another possibility is using STOP. STOP on the SFC input will trigger STOPPING sequence. In there, you can set start condition of the sequencer: "STOP = STOPPING" and then the sequencer is activated when you set STOP=1. You can create different logic in here, for example: stop a motor and after 5 seconds, close a valve. Its a normal stopping sequence.
How can I make a tag thats counts all the finished batches? Numberous ways, but if you are using STOP command, you can count (with a counter block), how many times the SFC state is "STOPPED". You can check the SFC output "STOPPED" or you can increment the counter in the END step of the SFC of the sequencer STOPPING.

How can I make a button to stop everything immediately? (I think Work with side step and then condition stop button = true towards the end?)

Set the output of the button to SFC input: "ABORT". The SFC goes to ABORTING and then ABORTED. The logic is already present in SFC, you only have to give the trigger.

Furthermore,
I have a level transmitter which is the most important input for my SFC, it has an analog input as an IB, could I just use a convert the byte to word block in order for the level transmitter to function?

I assume you use a driver block, where the input is scaled and an output is given between the range you give out. For example: A level sensor is set to driver block input and is scaled between 0-100. The output is then 0-100%.

Furthermore I have a valve which I only want to open for 0 seconds. (just a pulse open, and immediately close). If I add a timer and set it to 0 seconds that Q=1, will it still give this pulse to Q? or should I use miliseconds in order to make sure it really opens for a fraction of time?

You can use a trigger block for this. OpTrig or Trigger (depends on your library you are using). The trigger block will make sure that an output is "1"for one PLC cycle.

-----------------------------------------------------------------------------------------------------

water valve pulper is opened
Level Transmitter AGpulper reaches 5300 L (or other specific level to be determined)
The water valve pulper is closed
AG pulperMotor start
AgstortbandMotor start
AgdwarsbandMotor start
AgdoseerbandMotor start
Level Transmitter AGpulper reaches 7600 L (Or other specific level to be determined)
AgstortbandMotor stop
AgdwarsbandMotor stop
AgdoseerbandMotor stop
Timer starts for 35 minutes (Or other specific time to be determined)
After 35 minutes
AGpulpValve1 opens
AgpulpValve2 opens
PulperPump starts
Level Transmitter AGpulper reaches 6800 L (Or other specific level to be determined)
The water valve pulper is open for 0 seconds
The water valve pulper is closed
Level Transmitter AGpulper reaches 5500 L (Or other specific level to be determined)
ValveAGpulperpump canalwater  is opened
Level Transmitter AGpulper reaches  2000 L (Or other specific level to be determined)
AG pulperMotor stop
ValveAGpulperpump canalwater  is closed
PulperPump stops
AGpulpValve1 closes
AgpulpValve2 closes
Batch count+1
The water valve pulper is opened
Etc. sequence is started again
--------------------------------------------------------------------------------------------------

Hi Oreca, thank you for your advice, I will set the 'Cont' parameter in my block (see picture) to 1 in order to make it continous.

I see in my block that there is indeed an abort and stop signal. So if I set abort=1 everything stops and closes immediatly, or do I really have to make a new sequencer like you mention with abort=aborting and then specify all the pumps and valves that must switch off immediatly?

The only thing I would like in stop is that is finishes the sequence to end at ''end'' and not continue there after. Could I also make a button that set my cont parameter to 0 if the stop button is on?

I was thinking about the trigger block but after discussion we prefer to fill in miliseconds in a timer because then we can adapt the time when necessary

AGrS

Hi Oreca, thank you for your advice, I will set the 'Cont' parameter in my block (see picture) to 1 in order to make it continous.

I see in my block that there is indeed an abort and stop signal. So if I set abort=1 everything stops and closes immediatly, or do I really have to make a new sequencer like you mention with abort=aborting and then specify all the pumps and valves that must switch off immediatly?

The only thing I would like in stop is that is finishes the sequence to end at ''end'' and not continue there after. Could I also make a button that set my cont parameter to 0 if the stop button is on?

I was thinking about the trigger block but after discussion we prefer to fill in miliseconds in a timer because then we can adapt the time when necessary

 You have to create a sequencer which is started when abort is pressed. And you can make one if stop is pressed. But you can also make one sequencer which is started when abort or stop is activated. For this you have to set the start condition of the sequencer. And in the sequencer you can create the logic to stop everything. If you press stop or abort, the SFC goes from Run to Aborting (stopping) and then to Aborted (Stopped). In order to restart the SFC again, you have to set the SFC to Idle before you can start the SFC again.

Please find enclosed the SFC OSL-> Operating State Logic. This is how a SFC responds to actions and you can see which states are possible. This is how the SFC operates....

The abort sequence has been created with the required start condition (see picture), that was easy, and then thus it will close or stop all the relevant pumps and valves when the abort button is pushed

The only problem I have is when I push the stop button I dont know in which step I am. I cannot specify a certain sequence because this is dependent on the moment you push the stop button. After I push stop I just want to go to the end of my start sequence and then close or stop all the relevant pumps and valves. How would you tackle this problem? Maybe the solution is simple just make a transition condition for the beginning of my start sequencer: stop=false.

AGrS

The abort sequence has been created with the required start condition (see picture), that was easy, and then thus it will close or stop all the relevant pumps and valves when the abort button is pushed

The only problem I have is when I push the stop button I dont know in which step I am. I cannot specify a certain sequence because this is dependent on the moment you push the stop button. After I push stop I just want to go to the end of my start sequence and then close or stop all the relevant pumps and valves. How would you tackle this problem? Maybe the solution is simple just make a transition condition for the beginning of my start sequencer: stop=false.

 AgrS,

Please find enclosed (and in my next post) attachments. I think your start condition is not set correct.

Sorry for the confusion, but first you said to set ''abort''=''aborting'', or does this not matter, or must I set ''abort''=''aborting'' as the next start condition, 2?

AGrS

Sorry for the confusion, but first you said to set ''abort''=''aborting'', or does this not matter, or must I set ''abort''=''aborting'' as the next start condition, 2?

 Hi

Sorry for the confusion...

In my example, the correct syntax should be:

SFC(1).ABORTING = ABORTING, where SFC(1) is the SFC name and ABORTING is the output status of the SFC. You can even use input "ABORT" as well...numerous ways...

This way, the SFC is set to ABORTING state, and then the sequencer is started and executes the logic.

After that the SFC is automatically ended  to aborted state.

Hope this is clear?