Can I Program An Alarm Triggered by > 50% Current Draw on a given Axis?

    Hi there,


    We have two Fanuc M-410iB 700 Robots with an end-of-arm tool that has an additional FANUC servo motor (Group 2 Axis 1). It normally draws below 25% of max current but we have had some mechanical issues crop up that cause that current draw to increase to the point of overcurrent alarms and gearbox failure. We would simply like to monitor the current draw on this Axis and turn on a flag that we can use to display an HMI alarm if we go above 50% - to hopefully catch this early.


    I've done a bunch of troubleshooting of our existing FANUC programs but very little actual programming or configuration, so any help is appreciated.


    Cheers!

    Phil

    Hi moln4r, yes I think I do - a PDF here in my files called 'FANUC System Variables' that came with the controller.


    In GRP 1 we have collision monitoring, and the sensitivity is modified depending on what movement the Robot is doing. Could I set up something similar with GRP 2 where I can set the sensitivity?

    Here's the code to enable collision guard on axis seven and eight on a robot with one motion group.


    Code
    :$SBR[7].$PARAM[112]=(2097152/($SBR[7].$PARAM[47]))    ;
:$SBR[7].$PARAM[119]=7282    ;
:$SBR[7].$PARAM[120]=(-7282)    ;
:    ;
:$SBR[8].$PARAM[112]=(2097152/($SBR[8].$PARAM[47]))    ;
:$SBR[8].$PARAM[119]=7282    ;
:$SBR[8].$PARAM[120]=(-7282)    ;
    Quote from mortoch

    Are your robots using PLC's?

    If so CT's + analog input + compare/compute statement and you could conceivably monitor current.

    Yes our Robots are integrated with a ControlLogix PLC and we pass data back and forth all the time. I'm not sure what you mean by CT's.


    We use GO's to send INT values back to the PLC.

    How would I go about mapping that axis's current (Group 2 Axis 1) to a group output [GO]?


    Many thanks.

    I believe that will work for the second group as well. Just look at the values as they stand, if they're uninitialized it probably won't work, but if have values I would give it a try. Just remember to take an image first.

    CT's = current transformers.

    Place current transformers on the axis feed wires and send to an analog card in PLC.

    Then set max/min compare statements in program.

    Have never tried with robots but I have done this on many other machines.

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