dheater

OPC DA Interface UOM Conversion

Discussion created by dheater on Feb 5, 2018
Latest reply on Feb 13, 2018 by gmichaud-verreault

Q :How do you convert a raw signal input from degrees C to degrees F at the OPC DA level so the archive receives the temperature in degrees F?

A: Refer to the PI Interface for OPC DA 2.x manual, Scaling and Transformations section.

Use these values in Point Builder:

 

OutValue = [ (InValue - Dzero) / Convers ] * Span + Zero

 

Conversion factor = 1

Total Code = 1

Squareroot = 0

In Excdec, write the following: DZERO = 0

Span= 1.8

Zero = 32

Typical value = 33

 

This should result in:

[ ( TagVal – 0 ) / 1 ] * 1.8 + 32

or

TagVal * 1.8 + 32

 

NOTE: Make sure when you have “DZERO = 0” in the Excdec field,  include a space before and after the equals sign!

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