Cause & Effect Diagrams

[GOG]

For a new project I have to submit functional Cause & Effect diagrams for the complete control system of a power plant.
The way I've done this before is not accepted by my client. They stated that an international standard should be used for it.
Does anybody know if there is such a standard for Cause & Effect diagrams, which describes lay out, functional codes, etc.?

 

[Generation]

There is something specified in the NORSOK standards, which is available on the Internet.

Hope this will help.