Teach Pendant freezing when robot stops

    I have a strange issue that I need help on. So the robot (R-2000iA/165F) was executing the last move of a program when it suddenly applied the brakes and stopped. The program ran fine multiple times before this started happening. When this happened the teach pendant also went unresponsive. I power cycled and tried again, and the same thing keeps happening: the teach pendant freezes when the robot stops and while I can touch the screen and it recognizes that, none of the buttons do anything. When moving it manually I discovered that the problem seems to happen when I try to move Joint 4 past a certain position. I have set the Joint 4 and 6 axis limits to 9999999, so that shouldn't be an issue. I looked at the robot joint and nothing seems to be hanging up or colliding. I opened up the cabinet and when this happens the main board displays a 5 (servo alarm) and LEDs 3,4, and 8 (bottom two of the top set and bottom right of the second set, which the maintenance manual doesn't have a meaning for) are lit. The servo amplifier has the left three LEDs (two green and one red) lit, meaning an emergency stop signal is sent. I'm using a remote safety enable/deadman switch wired into the Model A remote I/O unit for the HOLD, SFSPD, Fault Reset, and Cycle Start signals. The IMSTP signal is wired to 24V always on. The main issue is that the teach pendant freezes when this happens, so I can't see the error. Please give any insight you have into this issue. I don't want to have to replace any boards, but I will if that's the only option. Thanks.

    Quote from WisconsinCheesehead

    I have had issues with TPs freezing and is usually a result of a bad CPU card, SRAM/FROM module or mainboard. Can you clarify the status of D1-D4 LEDs on the mainboard.

    Those are the ones in a square, right? The bottom two are lit. The maintenance manual says these two signal that "The initialization of the communication IC is completed." I should point out that I am able to start it up normally with no issue. This only starts when Joint 4 moves and the robot subsequently locks.

    On the mainboard there are 3 cards. CPU card, SRAM/FROM card, and Servo Card. I would order all the cards and mainboard and replace it all. You can take a chance at replacing individual cards and seeing if that fixes your problem. I usually don't do this because by not replacing everything you may wreck a brand new part. In the past a CPU card and mainboard resolved this issue. As far as jogging J4 to me it seems like it may be something with the servo card.

    I just switched out the main board and the problem persisted, so I'm fairly sure it's not that. I'm gonna try the amplifier next.

    UPDATE: it wasn't the amplifier either. I had pretty much much set the axis limits on Joints 4 and 6 to "none" and over the course of a few weeks' testing Joint 4's angular position got to over 8,000. I guess the system just *really* didn't like that, because I reset Joint 4 to its position within 360 and the problem went away. What a headache...

    Seen this before when someone set axis limits way beyond default. Glad you figured it out although I don't understand why the limits were moved so far past default unless this is a dismantled unit just spinning motors. Likely the software developers didn't think to put boundaries on axis limits with regards to specific arms and expanded limits on others like Nobot.

    You should set this thread to 'Resolved'.

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