Raspberry_Pi_SL + SoftMotionLight + Beckhoff EL7XXX

  • igunadi

    igunadi - 2020-04-07

    Hi there,
    I have been trying to configure Beckhoff EL7221-9015 (DSP420) but unable to make it work.

    So far I have only been able to add the drive but once I add the axis, the axis returned a configuration error.

    Any pointers?


    Last edit: igunadi 2020-04-07
  • eschwellinger

    eschwellinger - 2020-04-07

    Hi, not sure if this drive is possible to use with SoftMotion light.
    I would prefer to use it with SoftMotion. ( Sure you need a realtime Linux patch for your Kernel on this PI)
    If you go with Softmotion light you need to check if this drive is SML capable by this project:
    "c:\Program Files\CODESYS 3.5.15.x\CODESYS\Projects\SoftMotion\4.6.x.x\SoftMotionLight\SML_CompatibilityCheck_DS402.project"


  • igunadi

    igunadi - 2020-04-10

    Hi Edwin,
    Thank you for the pointer on using Softmotion vs Softmotion Light.

    Since last time, I have now used a Raspberry Pi 3 (RPI 1 is too slow to sync motion) and was able to get further.
    1. All EtherCAT seems happy
    2. Can go to config mode
    2. Able to turn on the servo. Motor is firm with no error.

    However when I try to jog, the position setpoint would change but the actual does not move anywhere. Any pointer?

  • eschwellinger

    eschwellinger - 2020-04-10

    In case of the error you should check the axiserror and logger in the plc -

  • igunadi

    igunadi - 2020-04-13

    Hi Edwin,
    I could not find axis error but here is the log on SoftMotion.

  • eschwellinger

    eschwellinger - 2020-04-15

    goto the watch windows and check
    in case of the error


  • igunadi

    igunadi - 2020-04-16

    Hi Edwin,
    Thanks for the hint above, I found the following similar post:

    I can now enable/disable/reset drive, and perform absolute move from configuration mode and LD instructions.

    On the next step for motion, how do you tune the servo motor. What interface do I have available for SoftMotion.

  • eschwellinger

    eschwellinger - 2020-04-19

    For Beckhoff drives you need to use Twincat for the drive comissioning.


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