RX90 - Joint 5 locked

[jespinos]

Hello, I can not move by hand joint 5 on a RX90 arm.

I have a RX90 arm with a CS7 controller.
I power up the controller and when the system finished loading OS, I can move the rest of joints by selecting them on the selector switch of the base of the robot but not the joint 5.

Do you know how to check joint 5 brake?

Thanks in advance.

[Jim C]

Can you jog joint 5 with out it make a horrible noise? If yes then the brake is releasing.

Joint 5 and joint 6 on a RX arm use worm gears. This type of gear does not like to back drive. While it is possible to move them by hand, it take a large amount of force usually involving some type of long lever to get enough torque. I don't recommend doing it.

You can remove the wrist from the forearm. On a RX90 you may have to remove the access cover on the forearm and disconnect the electrical cables to get clearance. With the wrist removed, the motors still attached to the wrist and the electrical connector hooked up to motor, do a brake release. You should be able to easily spin the couplings between the motor and wrist. This is the best way to test the brakes on joints 5 and 6.

One note, the RX60 does not have any brakes on joints 4, 5, or 6. It relies on the resistance of the worm gears to keep the joints from moving when powered down.

[jespinos]

Hello, Jim C

I can not move joint 5, I use a big lever and two guys with no results, no energized noise. Joint 4 brake is released when I push the brake pushbutton, and I can move Joint  6 by hand without excessive torque even without pressing the brake pushbutton, no noise like energized motor.

Please see attached pictures about OS messages and LED's status of the controller, because I am speaking with Staubli support at Spain and they are looking for some problem on OS, about SPEC config of the robot, that's it, they think that the arm is not right configured.

I think that it could be a wiring problem or a 030/MI-6 board damage
and I don't like to remove wrist because I have no experience with this arm and I don't know if after removing the wrist I need to make a calibration with special tooling.

Thanks in advance.

[Jim C]

You can remove the wrist without having to recalibrate the arm as long as you leave the motors connected to the wrist.

On the original RX90, the gear ratio on joint 6 was around 32 to 1, on joint 5 it is 75 to 1. You will not be able move joint 5 by hand even with a lever. You still could have a bad joint 5 brake, but you need to pull the wrist our and try to spin the coupling while the brake is released to find out.

The robot spec file looks right for the V+ version. The over travel errors are actually thermal switch errors from the motor. There were not any inputs for thermal switches on the controller and we were not using the over travel inputs. They just never changed the error message.

The thermal switches were always an issue. A large number of the motors had bad switches from the supplier. On later systems they were removed.

I am guessing that you have an older controller connected to a newer arm.  The controller is looking for the thermal switches, but arm does not have any. You could try to jumper the thermo switch inputs on the J2 connector of the safety board (J2 1 to 2, 3 to 4 ... 11 to 12).

This is a separate issue from the brake.

[jespinos]

I will remove the wrist, as a last option.

The controller & arm have the same serial number:
Arm Type: RX90   - Controller Type: CS7 RX90
Machine No: 1RP234-01
Fabrication: F-09-1996

For the thermal switches, I figure out that there is a direct wire from the J2 connector at the safety board to the plug connector at the base of the robot. I have D.280.075.24.B - Rev B 10/97 electrical drawing set, and the installled safety board is different (I have D.231.249.01). I suppose that you want to jump J2-1 to J2-2, jump J2-3 to J2-4  up to THERMO6. Please could you verify that the attached drawing is correct? "D_07524b-Safety - Pinouts.jpg"

I have never seen before a RX90 arm but, please take a look to the attached picture, the connector at the base of the arm had a hit.
I think that it is not normal, that's it,  the right hand connector pins look burned, see attached picture "IMAG0079.jpg"

What do you think?

Thanks Jim

[jespinos]

I found 2 female pins out in the air connector that fit to the base of the arm, I open the casing and I pull out the pins, and I fix the connector harness.

Then I load the new SPEC file that Staubli Spain support team send me.

Now the overtravel errors are go out. Joint 5 continue locked, and I when enable power a error message at the pendant say that JOINT 2 IS OIT OF RANGE.

I need to perform an absolute calibration procedure for this robot RX90.

[Jim C]

Loading the new SPEC file overwrites the calibration. Use brake release to move Joints 1,2,3 and 4 to their witness marks. Load the SPEC application and run it, "ex 1 a.spec". You will need to enter the "spec_cal" password to get to the maintenance mode. Record new values for all 6 joints (at this point 5 and 6 will not be on the marks). Save the system data from the main menu of SPEC. Reboot and everything should be good except for 5 and 6, but now you should eb able to get power on and jog them with pendant. Align them to the marks and run spec again for a final calibration. Once you have saved the system to your C drive, do it again to the A drive and you will have a back up on floppy.

[jespinos]

 B I C

 Best
 In
 Class

I a few words, CONGRATULATIONS to STAUBLI TEAM.

Thanks to Eduard & Jim for your support.

This is my first contact with the forum and with the Staubli support team and I am very happy with them.

I finished the Absolute Calibration and the robot is running.

Best Regards and See you soon.