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Analog card scaling issue

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  • Analog card scaling issue

    I am using a D06 controller and have a F0-08ADH-1 card to read pressures between 0-200 psi. I have done this with other brand plcs with the same sensors (Honeywell MLH025BSD14B) and never had any issues. I can get the scaling correct at the high end or at the low end by changing the engineering unit to try and compensate. The values are consistently off and stable. If I get the sensor to read correctly around 200psi it will be about 10-15 psi of at the lower range. The same is true if I get it correct at the lower range the high readings are off. e have checked for loose wires and proper grounding to eliminate any noise issue also have a better quality 24vdc power supply to also eliminate any power issues. I am using the the program from the back of the manual for the scaling.


  • #2
    If a linear scale does not produce acceptable results then the input is not linear. Using a spreadsheet enter as many input/actual pairs as you can in adjacent columns. Try to span the whole range. Then graph the result. I don't know if you have a faulty sensor system or just need a more complex scaling method.



    • #3
      You say you have used "the same sensors" with other PLCs, literally the same sensor or just the same type?, there is always a non zero chance a specific sensor could be faulty (same goes for the card too)
      Since mistaking 4-20mA for 0-20mA would probably be a much larger error than you are seeing I doubt that is the problem but one might double check.
      It looks like your sensor is a 25 bar (362psi) model, at 200pis you are only using a little more than half its range, that doesn't help things, but half isn't like, say, 10% so I wouldn't expect that to be a huge problem, but again doesn't help.