Micromotion pulse input to 1756-HSC

[phuz]

Just finished an upgrade from a SLC500 to CLX where they had a 1746-HSCE and we're now using a 1756-HSC. Two wire pulse signal from the micromotion mass flow meter. A+ / A- on the old card, and electrician hooked up to terminals 14/18 on 1756-HSC which looks like 12/24vdc and I'm wondering if the A+ needs to be on #16 for +5vdc. I can't find any info on what voltage the micromotion pulse is, but I would suspect 5.

Having a strange issue where the totalizer seemed to be operating correctly, and then on the next batch it was completely off. I also have the 1756-HSC on Counter mode with no filter enabled.

 

[phuz]

The micromotion is scaled to 60 counts per lb and they're running at 30lb/minute and showing 30hz on the micromotion pulse signal, which jives. However, the PresentValue is showing the count increasing at a rate of about 700 / sec. Not sure what's different on this card vs. the other. I did enable the filter which is good for anything below 25khz. I also just realized that the card in the program is a HSC/B and the actual card is a HSC/A. Keying disabled. Would that have an effect here?

 

[phuz]

Found the culprit. The customer had the signal wires run along/near 120vac VFD control wire and whenever it was energized it would take the incoming meter signal from 30hz to ~700hz. Temporarily ran a wire directly from the meter to the HSC inputs and no issues.