I have an application that reads Modbus data and display/stores in a database. I want to upgrade the application to have an engineering screen where the calibration team can enter in calibrated slopes/offsets and then have these corrections applied to my OPC tags, and then everything in the app should use these ‘adjusted’ values.
I did some searching on scaling but didn’t see much. Does anyone have design ideas? I need to have the calibration data available, so I assume I need to create my engineering page and have a button at the bottom with something like ‘write to database’. Then maybe when the app opens, I read all of these values (slope/offsets) into client tags, then do math? So create a whole separate set of tags…
Adjusted Tag = OPC tag * slope + offset
where Adjusted Tag will be a DB or Expression tag. I will then put the Adjusted tags into my transaction groups, into my trends, etc, instead of the OPC tags I have now.
There are scaling fields in the OPC tag setup, but that doesn’t look like it takes variables.
Thanks in advance for your design ideas!