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Analog module - Unable to get input or output

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  • Analog module - Unable to get input or output

    Currently running with a DL06 and the F0-2A2DA-2 analog module.

    I have a single 24Vdc power supply. I am supplying 24Vdc to the analog module. I am trying to read a transducer outputting 1-5Vdc. This transducer is powered by the same 24Vdc power supply.

    Reading the bare ends of the transducer output wires I get a 2.5Vdc signal, correct for what it should be reading. HOWEVER, when I plug these signal wires into the analog module, it immediately drops to ~0Vdc. Unplug it again and it reads 2.5Vdc. Acting like the module is shorting it out.

    I have tried an identical analog module in a different slot with the same result. I never setup the module in the software, I assumed it was automatic. Is there something I need to turn on???

    I will gladly provide more info as requested, unclear on what else might be needed.


  • #2
    Download the manual - http://www.automationdirect.com/stat...ionsm/ch12.pdf - read it thoroughly and make sure you are following the wiring diagrams. There are jumpers on the board to set the range of the signals.

    Read the example program information and follow it.

    If you wish post your wiring diagram.
    thePLCguy

    Bernie

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    • #3
      You should be connecting the negative (common) wire from your transmitter to the 0V on the module, and the positive from your transmitter to the IN !. Is this how you have it wired?
      Circumstances don't determine who we are, they only reveal it.
      Jason Wolthuis

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      • #4
        I believe my wiring is correctly following the manual. I have also set up a program verbatim from the manual (the PDF you linked above). Excuse my poor drawing, but this is the basics of my setup.

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        • #5
          Is the 24 VDC power supply dropping in voltage?

          Do you have a part number for the analog transmitter? (To verify the wire connections. I assume your wire colors are direct from the transmitter. if you wired from terminals on the transmitter can you verify those?)

          Otherwise your drawing seems essentially correct.
          thePLCguy

          Bernie

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          • #6
            Thanks for the assistance so far.

            Power supply is not dropping any voltage. Steady at ~24.14Vdc. Colors are not correct from transducer. Here it is:
            http://www.ashcroft.com/installation...cers-G2-T2.pdf

            I have red wire to +24Vdc bus, black wire to common bus and white to the analog module "1 IN".


            This info may be more telling. With nothing plugged into the module, I am getting a +5Vdc from nearly every terminal on the module to the 24Vdc power supply common.

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            • #7
              Good news is that I did get the output channels of the module working. So I know the module should be okay.

              Baddish news is that the input still does not "work." Though, I think I might have an issue elsewhere causing the signal to short out. I tested the transducer alone and it works as expected. Might be a missed common connection or something I am overlooking.

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              • #8
                You could tie the output to the input to verify the input, and your ladder is working properly.

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                • #9
                  Could there possibly be some sort of minimum current required from the sensor?

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                  • #10
                    Voltage input works using a standalone voltage source.

                    So something fluky with the sensor.

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                    • #11
                      In the end I tried another vacuum sensor that worked. Unfortunately its signal was too complex to make use with limited math functions on the PLC.

                      So I ended up with a vac. sensor from AD with linear output. Works as should.

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