IRC5 Seventh Axis Drive Overload

    Hey everyone,


    My division just recently inherited an IRB 6640 from another facility, and I've been trying to get it operational once again. This robot came from the facility with a seventh axis already installed. So far, the robot arm seems to work just fine, but once I attempt to jog the seventh axis, the controller spits out Event Message 50417: Drive Unit Overload Once this error has been displayed, any jogging motion triggers the drive overload (even from the robotic arm.)


    Here has been my process so far to try and resolve this issue:
    [list type=decimal]

    • Checked servo motor for mechanical interference by removing from seventh axis housing and attempting to jog. - Error 50417

    • Checked that mechanical brake was being disengaged.

    • Checked that servo shaft rotates freely when brake is disengaged.

    • Checked wiring in seventh axis junction box.

    • Hooked up oscilloscope to seventh axis resolver cable to check for noise.

    [/list]


    After measuring with the oscilloscope, I was able to examine the resolver signal. Since the drive would sometimes overload when I jogged the robotic arm, I had a hunch that I might be getting some electrical noise in the SMB cable. Attached are two pictures. The picture labeled "No_Noise" was taken before I engaged the motors, and the picture labeled "Noise" was taken after I engaged the motors. (Right after moving joystick to jog.)


    Has anyone had a similar issues with their resolver signals before? I would assume that the IRC5 would filter out high frequency signals, but This is roughly double the frequency of the primary coil, so it may be too slow to be removed by a low pass filter.


    Any other suggestions? I have been focusing on the SMB wire because it seems like the most likely, but I could be overlooking another key issue.

    Quote from Woodside_CAT


    Has anyone had a similar issues with their resolver signals before?


    If the problem is caused by interference on the resolver feedback, then yes. For me, it's more often a gap in the cable shield due to corrosion, wear, or improper splicing. Also have had improperly grounded shield on resolver cable, and wrong type of cable used (inadequate shielding). Double-check the shielding and try separating the cables to see if that helps.


    Not convinced it is the resolver signal though. Scope signal wasn't terrible and I would expect a speed or position type error.


    Double-check all motor cable connections for burnt spots. Disconnect the motor cable from the amp and use a megger at 500V on the cable any phase to ground. With the cable unplugged from the amp and the motor, meg between phases and each phase to shield/ground. I like to check the motor phase-to-phase with the milliohm scale to try to catch a shorted or overheated winding.
    Double-check the cable between the Main servo amp and the aux amp to make sure connections are good. Does amp still overload without the motor leads connected? Try another aux amp if you can.

    The error 50417 has nothing to do with resolver signal. It means there's over temperature inside drive unit on controller. As you told you have this error even on system startup, probably you have a defective drive unit.
    You have to replace drive unit or send this one to repair.

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