RESOLVER ERROR / SYSTEM FAILURE

    Please help!
    I have an ABB 6400 S4C robot that keeps faulting out mid-program. It trips the following errors:
    38031 Resolver Error
    39103 Mains Missing
    10020 Execution error state
    20202 Backplane Enable open
    10014 System failure state
    20012 Sys failure state active
    10005 Program stopped


    When this happens, I have to power cycle the robot in order to get it to do anything, and every time I do this, I have to update the rev counter for axis 6
    Any help is appreciated, thank you in advance.

    First, doublecheck the connections at the SMB, upper arm connection box and axis motor. Inspect the cables and grounds.
    Try jogging the robot near where it always gives the fault and try to get the error to stay. It will make it easier to troubleshoot. If it does stay faulted, try measuring the axis 6 resolver resistance from the SMB connector.
    If you can't get it to stay bad, move the robot to the cal position and then try a known good SMB first - it's much easier to change than the cable or the motor.
    Do not physically remove or adjust the resolver, it is aligned to a commutation position. Moving the resolver will likely cause motor issues.
    Besides the SMB going bad, the axis 6 wire harness tends to fail at the base of the coiled part right where it goes into the tilt housing (axis 5).

    It was indeed the axis 6 wire harness. We ohm tested the wires from one end of harness to the other. Third wire we checked, was bad , would go in and out if jiggling the harness ( at the base ).
    After removing the harness and ordering a new one thru ABB ( $1478.00 ) 3HAB7423-1
    WE Dug into the wiring and found 1 wire completely broken in two and 2 more very close to the breaking point.
    I hope this can save someone a lot of headache and downtime.
    Thank you SKOOTER for your input.
    AND it turns out we now have a good used SMB should anybody need one

    If its on all 6 axes, I'd be inclined to try a different SMB...
    I'll see what I can find for resistance values.


    I checked a 2400L - at the resolver(9-pin):
    1-6 = 200
    2-7 = 200
    3-8 = 36


    Resistances are similar at SMB(25-pin) except FB1 and FB2 (as well as FB5 and FB6) share Excitation (3-8) so reading is 20.

    Edited once, last by Iowan ().

    It's been my experience that while resolver signal missing errors will not permit motion it will not put the control in a system failure state. If serial data is missing the control will enter a system failure state.


    I concur with Iowan, another SMB try may be in order.


    If the SMB cannot generate an excitation signal it may flag the control to invoke system failure. Since resolver pathways were checked, it might not be a bad idea to check continuity on the serial pathways. SDI, SDI not, SDO, and SDO not.

    So today i try 3 SMB Boards... result: allways the same
    so i mean is not the SMB
    i found a problem with the power supply from the Controller
    after the trafo unit i have on the secondary site only on 2 wires 260V, one have only 90V.
    on primär i have 3x400V


    its realy not easy to remove the trafo unit :grinning-smiley:....
    i'am process to replace it from another controller....

    very helpfull vegas 1288
    only this week one of my robots has been giving the same problem with axis 6
    has anyone considered splicing both connectors onto new cable between motor and base cable connections behind smb?

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