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GS3 Drive to GS-EDRV Comms Issue

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  • GS3 Drive to GS-EDRV Comms Issue

    I am controlling GS3 drives, 75HP x2, along with 10HP x1, from a Do-More BRX, via GS-EDRV modules. The smaller drive runs fine without issue. When the larger drives are started (simultaneously), the RS-485 communication side of the GS-EDRVs drop out, indicated by a loss of updates to the drive structure data. The Ethernet I/O monitor show no lost packets,
    nor do the .$drive.ExtCommFault and the $drive.IntCommFault bits indicate any failure. However the STAtus LED on the GS-EDRV may go off and the structure data will remain frozen
    until comms are re-established. We used the standard cable provided with the GS-EDRV for the RS-485 side, but will be changing it out for a shielded cable as one possible solution.
    We lowered the carrier frequency of the GS3 drives from 6KHZ (default) to 1KHz per recommendation of ADC tech support which made some minimal improvement but still comms
    loss remains. I am looking for suggestions from anyone who may have dealt with this issue in the past. The drives by their nature emit considerable electrical noise and the RS-485
    comms to the drive are vulnerable. Suggestions or solutions most welcome!

  • #2
    I have not dealt with this issue before, but I would imagine that starting such large motors is putting out a very strong magnetic field and this is causing your comm loss.


    • #3
      Are you getting a voltage drop when the 2 75hp motors start that is bringing down the voltage. We have a portable plant that runs off a generator that if the biggest motor isn't started first the generator bogs down when it starts that drops our voltage below the minimum threshold. The motor I'm talking about is a 250hp though.


      • #4
        No Brueck, the power is steady. It seems that the drives generate enough noise such that the unshielded flat RS-485 cable that comes with the drive is affected.
        We are going to try shielded cables tomorrow to see if that improves the situation.