(E1339)[MC1]P-N high voltage.(Servo board1) (E1338)[MC1]P-N low voltage.(Servo board1)

    Hi guys,


    Has anyone come across (E1339)[MC1]P-N high voltage.(Servo board1) fault followed instantly by a (E1338)[MC1]P-N low voltage.(Servo board1) fault?


    After the the initial faults resetting would result in only (E1339) P-N high voltage fault.


    After cycling the power the robot produces the following faults:

    (E1339)[MC1]P-N high voltage.(Servo board1)

    (D1566)P-N capacitor has not discharged.(Servo board1)(MC1)


    The MC unit was replaced with a known good unit that was tested on a working robot.


    Initially no faults until the servos were powered up to hold position.

    then the following faults would occur again:

    (E1339)[MC1]P-N high voltage.(Servo board1)

    (D1566)P-N capacitor has not discharged.(Servo board1)(MC1)


    Original MC unit and now bad MC was put into the known good robot and still displays the same errors:

    (E1339)[MC1]P-N high voltage.(Servo board1)

    (D1566)P-N capacitor has not discharged.(Servo board1)(MC1)




    This leads us to believe something on the bad robot/controller is taking out MC units when servos are powered up. We are currently in the process of looking for bad connections, shorts circuits in the robot harnesses and next will start checking inside the controller. Just want to know if anyone could shed more light what else we could check or have any theories on what might be the root cause.


    We have one spare good MC unit left but don't feel confident putting it in until we find something on the wiring or explanation on what could be destroying the MC units.


    Current theory is hinging on bad wiring, short/disconnection or potentially a bad regenerative unit/resistor which are used on E43 controllers.


    This is on an E43 controller with a ZD130 robot manufactured in 2012.



    Snippet from the error log below of the original fault :


    860 - [20/02/10 06:59:01 SIGNAL:00 MON.SPEED : 69 REPEAT mode]

    (E1338)[MC1]P-N low voltage.(Servo board1)

    OPERATION1:[20/02/07 03:57:58] ( CYCLE START )

    OPERATION2:[20/02/07 03:57:58] ( Motor power ON )

    OPERATION3:[20/02/07 03:57:02] ( CYCLE START )

    ROBOT1:

    PROGRAM:pg0 Step:130 Cur_Step:134 STATUS:WAIT

    Interpolation Type:JOINT S_parameter:0.000000

    PC1 PROGRAM: pos_create Step No: 40 STATUS: STOP

    PC3 PROGRAM: autostart3.pc Step No: 18 STATUS: WAIT

    JT1 JT2 JT3 JT4 JT5 JT6


    -42.963 44.488 -7.361 -139.542 0.000 0.000


    ------------------------------------------------------------------------------

    861 - [20/02/10 06:59:01 SIGNAL:00 MON.SPEED : 69 REPEAT mode]

    (E1339)[MC1]P-N high voltage.(Servo board1)

    OPERATION1:[20/02/07 03:57:58] ( CYCLE START )

    OPERATION2:[20/02/07 03:57:58] ( Motor power ON )

    OPERATION3:[20/02/07 03:57:02] ( CYCLE START )

    ROBOT1:

    PROGRAM:pg0 Step:130 Cur_Step:134 STATUS:WAIT

    Interpolation Type:JOINT S_parameter:0.000000

    PC1 PROGRAM: pos_create Step No: 40 STATUS: STOP

    PC3 PROGRAM: autostart3.pc Step No: 18 STATUS: WAIT

    JT1 JT2 JT3 JT4 JT5 JT6


    -42.963 44.488 -7.361 -139.542 0.000 0.000

    Apparently there is one fan that isn't operational. There are also signs of corrosion. I'll find out which fan is not working.

    I'll have to check regarding the manual brake release. I believe the 24v DC from the 1TU board is intact, but will have to get back to you.

    I ask this, as I have experienced issues some of the FETS on the 1TU board failing during power cycles.

    This was a good 4 years ago, but I went down to component level and discovered the FETS were actually discontinued and the equivalent was a higher spec device, which I fitted and never had further issues.

    I did this on about 10 1TU boards in total which had failed in the same way.


    The main power that the control voltages are derived from on the 1TU are supplied by the AC40 supply from the mains transformer (it is this AC source, I believe was responsible for the failing).

    This source provides the supply to the fans, supply to the brakes and what they refer to as the 'hot' control voltages for the power electronics (separate from the AVR voltages).


    In addition, it also contains the controlled bridge rectifier to provide the PN voltage which also contains the power transistor or IGBT (can't quite remember which) that is used to charge/discharge the PN circuit and also the regeneration circuitry.


    The point I am trying to make, is that I have experienced something similar with the 1TU boards failing and the conclusions were down to inrush/transients coming from the main incoming supply.


    Worth checking your incoming supplies I think for clean and balanced phasing.

    Incoming power supply was checked and well within tolerances. But we suspect there was a power anomalie when the original fault first appear. Either a spike or a brownout or unbalanced phase. It's just that usually when there is bad incoming power supply there are other fault numbers that usually come up when 2 phasing and generally out of the expected tolerances.


    Either way I think you are correct that it could be the FETS and related to the AC 40 volt supply/ incoming supply.


    Unfortunately due to the time pressure on this, I believe the process has begun on replacing with a CP180 and an E03 controller.

    But having said this, it gives us a bit more time to investigate the old controller and i'm sure we will find the root cause.

    Just an update, it was fan #7 on the external regen resistors. There are corroded terminals on the fan.


    The robot motor brakes on jt1 and j4 were releasing ok and the 24Vdc on the brake circuit was measured at 24v. Other joints were not released due to its positioning and gravity being constant at 9.81m/s2.


    Resistance across the regen was measured and tested ok. No shorts between resistors, fans or the thermal switches were found.


    Checked for shorts between all motor phases and
    the break coils and ground     and were all ok too.


    Robot harness cables were meggered and no leakage to earth/shield or other motor phases.

    That's what I call a thorough check, including meggering the cables...…………..:top:

    If the fan was short circuit, maybe......but just corroded terminals, I doubt would cause any disturbance on the supply line.


    Previous C/D Controller

    - Brake supply off the mains transformer was 21-26VAC and was purely for the brakes and brake control.

    - Fans were supplied from a separate transformer tap at a mains level.

    - Control logic was sourced from the AVR.

    - Control voltage for the power amplifier PWM was sourced from the AVR.


    E Controllers

    - They have consolidated all of the above from the AC40 tap off the mains transformer.

    - Brakes are at 24VDC level.

    - Fans are at 24VDC level.

    - Control logic is still sourced from the AVR.

    - Control voltage for the power amplifier PWM, PN and Regeneration monitoring is sourced from a 20VDC derived from the incoming AC40.

    - These were the FETS I was referring to - they form a SMPS for the 20VDC hence any issue electronically on this line whether it be the FETS or other components could introduce a whole host of PN, Regen errors.


    What you've described points to power surges...…….. IMHO

    Quote

    It's just that usually when there is bad incoming power supply there are other fault numbers that usually come up when 2 phasing and generally out of the expected tolerances.


    For sure, Kawasaki never really introduced any incoming phase monitoring, phase ordering errors.

    So you could swap the incoming phases over and suddenly you would receive different errors, controller power cycling etc.....Very misleading.


    I think on the F Controllers, they do have phase monitoring now, not sure about the universals, but I expect they do on the E03 controllers with the regeneration option feeding back into the mains.

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