Symbol (Tag) Naming Conventions for PLC Programming

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Thread Starter

Richard Forrester

I need a tag naming convention to help me accurately translate infomation from P&ID drawings to my PLC programs. Is there some kind of standard out there that is the programmers equivalent to the ISA Symbols and Identification Standard?
Example:
A symbol shown as R300 PIT on a P&ID drawing works well to show the origin of an analog signal going to a plc, but once it is in the realm of software, what do you call the unscaled value, the scaled value, the filtered value, the limited value?
If anyone knows where I can find such a standard, I would greatly appreciate your help.
thanks,
Rich
 
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Bob Peterson

> A symbol shown as R300 PIT on a P&ID drawing works well to show the
> origin of an analog signal going to a plc, but once it is in the realm
> of software, what do you call the unscaled value, the scaled value, the
> filtered value, the limited value?

I don't think there are any official standards so I have made my own conventions.

For example:

PIT1001 is the instrument name

PLC symbol names

PIT1001 = raw analog input value in the PLC

PI1001=scaled value

PAL1001SP=setpoint for the low alarm
PAL1001=alarm bit
typ for PAH, PALL, PAHH

Bob Peterson
 
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ITS SHAHID WAQAS CHAUDHRY

We normally use a pretty similar conventions to Bob:

Area.ItemName.Function
e.g.: The Feedback of a motor on an plants Ammonia area would be:
Ammonia.Motor101.FB

But usually every programmer has his/her own symbol/tag naming convention!

Best Regards,
Shahid Waqas Chaudhry
 
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