Documenting what happens within a control system. 1

[davelashley]

I am looking for an effective way of documenting what happens within a control system.

We produce PC controlled skid mounted process kit. Pumping, mixing and sampling systems controlled by a PC via a Profibus network. Increasingly we are asked to produce “control logic diagrams” as part of the design package. Simple logic yes/no flow charts do not seem to have the capacity to detail the inner workings of the system. Granted they are fine for high level overview type applications but I need something more sophisticated. I am sure I have seen a reference to a standard for this kind of thing but the location escapes me.

Any help or advice in this area would be very welcome.

Thanks

 

[IRstuff]

Any reason a standard computing flow chart wouldn't work?

TTFN

FAQ731-376

 

[Compositepro]

Search for ladder logic diagrams.

 

[jraef]

Such is one of the drawbacks of using PCs for control instead of PLCs. However if you used a programming software package designed for industrial controls, it may possibly have a logic diagram documentation feature or option package, check it out with the provider. If you "rolled your own", it sounds like you probably forgot to include that as a development cost when comparing to buying something ready-made.

 

[GTstartup]

Or boolean logic

 

[ScottyUK]

Google "SAMA diagrams" without the " ". They're typical of what we use in the power industry. Probably outdated and outmoded, but we are an old industry and we like them!

First link for free - there are dozens more on the net. The Siemens ones seem pretty good on the whole - maybe a legacy of the Westinghouse buyout?

http://www2.sea.siemens.com/NR/rdonlyres/2B00B4DA-6A47-4F82-9550-A28C4F2FFC67/0/AD353131r1.pdf

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

Sometimes I wake up Grumpy.
Other times I just let her sleep!