Process vs Drawing IDs

Just wondering for those of you who work on process machines, do you typically make your drawings follow the ISA designations or do you have double IDs for your devices?

I know in the automotive world everything is labeled by page #, line #. For example, if I had a float switch reading the level in a tank by NFPA designations it might be identified as 1114FLS if it were on page 11 line 14. However, in an instrument diagram it might be identified as LS01 or LS02.

Do you just use the instrumentation IDs in the electrical drawings or follow through with the page# / line #?

I haven't had a customer call us out on this, but we have had several jobs recently where we are creating a P&ID diagram and the symbol IDs don't match the electrical drawings and it drives me crazy (personally). I'd like to use one and stick with it, and I'm leaning toward using the process ID, but I'd really like some opinions before I run with it.

Page and Line number with the 3 letter nomenclature is the basic way most people use there prints.

If you divorce the above and use the Process ID, how do you find the wiring inside your set of prints, page and line number? Either you have an attachment with a cross reference the process ID with page and line number where the wiring is shown? Somewhere you need something to marry the two pieces of info together.

I tend to just go on the electrical drawings with wire number and ID.

Someone goes through the trouble of making the electrical drawings meaningful and descriptive, I take full advantage and use their info.

No point boiling your cabbages twice.

I used page/line number for wiring and PID tag number and description for device identification.

We do the same as Tom Jenkins. We also include the page/line number on the field device tags.

In our systems, the tags on the P&IDs are used to name the Objects in the code.

For example LI_123 is a level indicator, this will match the tag on the device on the HMI and the actual stainless steel tag on the instrument in the field. In the software, the object will have that same tag for the routine and software objects/instructions.

The wire numbers to and from the device are referenced in the drawings and go by either I/O address and drawing page and line number.

When i worked for my past employer we used to do the P&ID first, then the electrical schedules would be based on this and lastly the programming would also use the same designations.
Very easy to follow all the way when everything has the same name everywhere. Ofcourse you need a solid system to name it all - we preferred KKS.

As a system integratorion design engineer who did a lot of both industrial and process control work I always found process control panels nomenclature to be more difficult than industrial panels .

Many devices and wiring related to a panel don’t have anything to do with a process control loop. Example: an interior panel light and door limit switch, or an alarm horn that is triggered by multiple loops.

Most PLC discrete outputs were wired directly to interposing control relays inside the panel. There were typically many, many spare relays included. How are those labeled or what ID# is assigned to it and shown on the drawings?

What I started doing was using page# / line#’s for devices and wiring internal to the control panel or not related to a specific process loop.

Process control devices usually had their ID #’s assigned to them by the consulting engineers so naturally those were used on drawings & documentation.

It wasn’t a perfect system but there was a method to my madness that I could justify.