CFC Programming Question

[FIN]Pete · Jun 11, 2009

Has anyone good ideas how to do short sequences (up to 8-14 steps), using the CFC-programming? The goal would be that the program would be a clear, simple, easy to modify. The main thing is to find a good idea of how the sequence of CFCs has worth to do.

Please do not suggest endless (FlipFlop, And, Or, Edge), diagrams or the SFC to.

Pete

cjd1965 · Jun 11, 2009

Hi
Which PLC etc or u looking for a generic solution?

I would use a register to hold a value for the step number, say 0 to 16 steps.

Use compares to create step active bits. Use step complete coils to move next step nmber into the step number register

[FIN]Pete · Jun 12, 2009

Clarification question: it is a Simatic PCS7's programming tool. I have been thinking about a step numbers one way or another. Unfortunately, I have not found a good way to set a several values for the same variable.

Nick B · Jun 12, 2009

Use the tool that is meant for it SFC. This is a standard programming environment for PCS7

[FIN]Pete · Jun 16, 2009

There are already more than 20 SFC's. They are not worth "wasting" an easy and simple sequences.

As I said at the beginning: "Please do not suggest endless (FlipFlop, And, Or, Edge), diagrams or SFC"

Maik Fuchs · Jun 16, 2009

I would absolutely suggest to use a SFC. CFC's are used to connect different parts of a program not to make a program or sequence. You could also use a block created in SCL, FUP or whatever you prefer.

[FIN]Pete · Jun 18, 2009

I tried the "stick" of ice. I was hoping that someone would have been a good idea on how to make short sequences of CFC holds.

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Pete

TurpoUrpo · Jun 18, 2009

Why do you want to force tool that is not meant to it, to do it? As Continuous Function Chart is just that..

mellis · Jun 19, 2009

Not sure I get how SFC's are "wasted" on short sequences. Seems like you're just being arbitrary in your programming style. Why should one project have two ways of doing a sequence?

However, I do have a suggestion if you want an alternative to SFC for sequencing. Write a custom block (or blocks) using SCL. Make it do whatever you like. I doubt you are going to get a very elegant solution using standard blocks.

Code like this should be kept to a minimum and documented thoroughly. And it should have a really good reason for existing in the first place.

[FIN]Pete · Jun 23, 2009

OFF TOPIC:

I agree with that, one program and one programming style. I do not explain the reasons for my question on the topic but just for clarification: those short sequences are intended for small, similar, independent, operational entities. Reason or another, SFC is not always an ideal choice for everywhere.
Simple is beautiful ....

Thanks for all..

CFC Programming Question

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