I have a CompactLogix PLC with an 1769-IF8 AI Card. My level transmitter is a 4-20mA, and my tank level can be between zero and 35 gallons. In RSLogix 5000 I see what is called "Engineering Units" for the card configuration simply is 4,000 to 20,000....this to me in a sense is still "counts" - because in ladder I'd still have to do something to match 4,000 to 0 gallons and 20,000 to 35 gallons, right?

What should I use in Ladder? I've read in the forum for a similar question that someone recommended a CPT block. I'm not sure how I'd use that to do my scaling. Any suggestions on specifics for the CPT block or another way to do my scaling?

I have to imagine this is done everyday by a lot of you out there (I'm new to A-B).

Thanks.

Arun

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Slight Improvement.

Add two checks to this CPT
LES TankLevel 0 Mov 0 Tanklevel
GRTTankLevel 0 Mov 35 Tanklevel

The 1769-IF8 actually goes 3200 to 21000 when in 4 to 20 mode. Anything under 3.2 ma reports as 3.2 and anything over 21 reports as 21.

Be careful, clamping signal can give the illusion that level sensor is perfectly calibrated at all times.

Thanks Guys. Awesome. One last follow up question: If I had a ControlLogix with a 1756 AI...I wouldn't need to do this, right? It looks like perhaps you can take care of this at module configuration in RSLogix 5000...?

Thanks,

Arun

That's correct.