Control loop numbering on P&IDs

[Procman]

What would form part of one single control loop? I have level in a tank that speeds up or slows down feed pumps on low and high level. The same tank level will also close a feed valve (on/off valve with limit switches) on high high level. Would the level transmitter and associated level indication and alarms, as well as the SIC's on the pumps and the ZSO/ZSC (limit switches on valve) be the same control loop and therefore have the same number?

 

[jalvarez]

I don't remember mandatory practices for this.
My experience is to use the same numbers for all pieces of hardware related to a transmitter.
It would be interesting to see others opinion.
Have a safe day
J.Alvarez

 

[CARF]

Yes,

I would say

LT001 : Level Tranmitter 001 (the level sensor)
LIC001 : Level Indicating & Controller 001 (the PID controller)

SIC : Speed Indicating & Controlling => wrong here, you're controlling level, speed control through a Variable Speed Drive is just a method to control level.

The rest of the stuff, the same number.

see :

ISO 3511-1:1977

Process measurement control functions and instrumentation -- Symbolic representation -- Part 1: Basic requirements

http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=8869&ICS1=25&ICS2=40&ICS3=40

and also part 2 and 3.

Hope this helps,
CARF

 

[Procman]

Thanks for the help.

CARF,

only when I thought about the loop numbering did I also wonder about the SIC. It is a level controller as you rightfully said, however, how do I indicate that the pump actually has a variable speed drive?

 

[CARF]

What I mostly do is put "VSD" with the name of the pump on the P&ID, so:

VSD mono-pump
PU710
crude oil

Do not know if this official standard, but very clear for all people how work with the P&ID drawings.

Regards,
CARF

 

[Procman]

Carf,

thanks. Similar was suggested by our instrumentation guys.