Interlocking diagram

Is there some standard for making interlocking diagrams?
I have to make some interlocking diagrams for plant that makes compost.

Interlocking diagram, in our terms, should say if some mashine goes off because of a problem or some other reason, which mashine should PLC software switch off.

Thank you.

I am not aware of anything internationally recognized, though that is not to say it's not present. The company I work for has a group who defines these as corporate standards that we follow. Mostly, these vary greatly from machine to machine. What is standard and does not vary is the process that is used to identify what hazards must be protected against, and what methods to use to protect against these hazards.

What type of diagrams? Electrical? P&ID's?

On P&ID drawings, I put a diamond with a capital "I" and a number on the interlocked device, and the initiator device also. Then in the drawing notes, I put the diamond again, with text describing the interlock. Something like:

When temperature transmitter TT-100 exceeds 100 C, control valve TV-100 will be interlocked closed, and cannot be opened until TT-100 drops below 95 C.

Lesa said:

Is there some standard for making interlocking diagrams?
I have to make some interlocking diagrams for plant that makes compost.

Interlocking diagram, in our terms, should say if some mashine goes off because of a problem or some other reason, which mashine should PLC software switch off.

Thank you.

Click to expand...

Understand the requirement is digital process application.

The logic requirements can be prepared

1. In the form of write ups which explains the sequences of start up, preconditions for respective equipment/process, interlocking requirement for announciation/trip to take care of safety requirements and safe shut down of the equipment/process.
2. NEMA or SAMA/ABMA standards have symbols for gates like AND, OR, NOT etc. These symbols can be used for preparing the interlog logics
3. Can also be prepared in ladder logic form which is used in PLC programming.

R.Thiyagarajan

The Norsok System Control Diagram standard is quite interesting, but I have not heard of many people using it.
It covers a lot more than just interlock diagrams. To my surprise you can still download it.
http://www.standard.no/pronorm-3/data/f/0/10/04/5_10704_0/I-005.pdf