SRVO-037 IMSTP

    Fanuc R-2000ib/210f Robot. R-30iA controller.

    Robot is controlled by a PLC through ethernet but keeps randomly stopping with a SRVO-037 IMSTP alarm. Some cycles it runs without issue, but others it will stop with this alarm. I am not a PLC programmer but I assume this alarm is triggered from the PLC? Any ideas on what could cause this would be appreciated.

    The IMSTP-signal is part of the remote interface and needs to be TRUE for the robot to be able to run.
    The reason you get the SRVO-037 alarm is because this signal dropped (turned to FALSE).

    Since this signal is coming from a PLC (through Ethernet), then you better find out why the PLC resets this signal.

    We are trying to find out but our plc programmer can't find the issue.

    He monitors the robot heartbeat and thinks that we are dropping the heartbeat which is sending the IMSTP alarm. The heartbeat is configured through an output for the plc to monitor. When I watch the teach pendant, every now and then the output does appear to get stuck on either off or on for an extra second or two. But I believe that is just a lag because the cell interface is working correctly.

    The visual representation of signals on the TP is not the same thing as the actual status of the physical signal (bus or hardwired). There's always the factor of lag in the display and so on.

    Don't know how your heartbeat function is set up, but it would be possible to build a simple heartbeat function using BG Logic.

    Also, to be clear, the PLC isn't sending an IMSTP alarm, the IMSTP signal drops (whether it's due to logic in the PLC, bad connection on the bus, or whatever), the robot recognizes this state and issues an alarm (SRVO-037) because of this state.

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