Mechanical Harness Issue Tiny IRB 1200 Robot

  • I took a functioning cable set out of the robot. Replaced it with another one and am getting this alarm. abb resolver values x low voltage y low voltage. 38209 error.

    I feel like all the cables are connected to each appropriate motor. MSB board is plugged in and communicating. I might've shorted something since it's a low voltage resolver error fault, right?

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  • SkyeFire

    Approved the thread.
  • @Skooter


    SO! I took the original cable harness and connected everything on the outside of the robot right. Left the new cable harness inside just disconnected. Had the same faults. SMU you mean the smb card right? best part its dangling outside the robot constantly since its a shop training robot. Error is only in axis 2.


    What makes me worry is I originally only did this because the old harness would randomly have a ovc alarm causing it to stop but it worked originally. I didn't take pictures of the connections like the manual instructed to do. I'd assume the cables are label simple enough to just plug and play into each axis motor. I guess not.

    • Helpful

    For me:

    SMB = Serial Measurement Board is the PCB.

    SMU = Serial Measurement Unit is the entire unit - metal mounting frame and PCB.


    I'm a proponent of making sure the SMU frame is grounded and the cable shielding grounded. Fixes noise that causes other, sometimes intermittent issues.


    Have you tried another SMU? Do you have another ABB motor to try just the resolver - resolver connections are standard across many ABB motors.

    NOTE! Do not remove or loosen the resolver.

  • Skooter


    What cable is the resolver going to the motor r2. mp1,2,3,4,5,6? I need a connection example of how to connect each cable back into each motor. The tags seem simple, but I could've plugged in one of them wrong to cause this issue. I also plugged in axis 2 motor cable into the SMB by mistake and had a communication failure between board and cabinet could this of fried the board? I swapped the cable around and the board turned on with good communication but a that error 38209 occurred.

    Edited 2 times, last by one0fakind: reasons :) ().

  • Thank you +1 rep Skooter

    I attached a axis 5 motor to axis 2 connections and it worked. I sadly updated rev counters while the robot wasn't at zero but shouldn't matter I hope? I need to buy a new axis 2 motor. I don't know how it went bad.

  • Regarding rev counters, jog all axes to their zero position and any that don't match - update those counters.

    Closely double-check the pins in the resolver connector for axis 2 motor. Perhaps a pin is pushed in or bent.

    After axis 2 motor is changed or removed, you will need to do a Fine Calibration on axis 2.

  • is there anyway to swap the resolver for motor two ? out instead of replacing the whole motor? or can't dismantle it? I need a part number and the pins look great on the motor power/resolver.


    Could this have happened due to plugging in the SMB power cable into the axis 2 motor by mistake and shorting the motor out? Since the motor was working in the past.

  • See note in post #4. The resolver is precisely set to a specific position on the motor to give it a commutation of 1.5708 rad. Any good servo motor repair shop familiar with ABB motors will have the equipment and knowledge to set the resolver to the correct position.


    I don't have the IRB1200 in front of me to understand how the SMB power cable could have been plugged into the motor resolver connector. Pins 3 & 7 in the power cable are the 24VDC and pins 3 & 7 at the motor resolver connection should not have continuity. The resolver should have resistance between pins 1 & 6, 2 & 7, 3 & 8. Resistance should measure the same between 1 & 6 and between 2 & 7.

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