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STP-DRV-4850 Seek Home Issue...

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  • STP-DRV-4850 Seek Home Issue...

    I am using a STP-DRV-4850 to drive a stepper motor and cannot get the "SH" command to respond for the life of me. I am using 3 prox sensors to emulate a "home, end of travel CW and end of travel CCW". I have tried using just a "SH3L" with the driver software set to "CM7" (pulse and direction) and also a "DL1" and then the "SH3L" with the driver software set to "CM21" (point to point). At one time I had the motor turning when the SH command was sent but the sensors were not signaling (they were firing but not stopping the motor) but like a fool I did not save that iteration and am now deep in the grass and am getting no motor response when the SH command is implemented. If anyone has insight as to what settings the driver software need and if I can simply do a SH command with the sensors as always I would really appreciate it. This one has truly got me stumped...

  • #2
    Guess I should have also mentioned that I am using a P1K PLC with the drive, if there is any other pertinent information that I have left out please let me know.


    • #3
      "SH3L" would say move until the enable input goes low. If you are using a normally open sensor, then the enable will most likely already be low. So your command could be executing but it immediately thinks it is done as soon as it starts because the sensor is opposite what the command is expecting. If you use a NO sensor, you could either use an SH3H command, or switch to a NC sensor. NC sensor is safer because if power drops out then the sensor looks like it is triggered so commands wont execute, which is safer than the same station on a NO sensor the command would execute and move past the sensor because it would never trigger without power.

      When using seek home, dont forget to use "DL" before to ensure your CW and CCW limit switches are defined and active. DL1 for NO sensors and DL2 for NC sensors.
      Last edited by MikeN; 11-18-2019, 10:37 AM.


      • #4
        The sensors are indeed N.O. ( I really like the N.C. sensor idea for safety and will lobby to change them but this is what I was given to make work for now, currently using Automation Direct P/N-APS4-12M-E2-D Koyo prox sensor) so I will try the SH3H command along with the DL1 and see if that will get me going. I may also need to double check my wiring but the sensor was sending an input signal and I am assuming that was going to the drive (trying to use the EN, STEP and DIR functions). The project is at home and I will have to retry it and will provide an update tonight (PST). Thanks for the insight and confirmation!


        • #5
          Just to follow-up, the DL command only works when you are in point-to-point (CM21) or analog position (CM22) modes. Any other modes have the STEP and DIR inputs predefined.

          This version of the SCL manual has a lot of details left out of Automation Direct's (or Applied Motion's) SCL manual (including the command mode limitations on the DL page). Hope this helps!