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Overview
The Denso RC8 and RC8A series robot controllers can occasionally generate overcurrent errors. This is not always cause for alarm, but the presence of the errors does sometimes mean the arm or controller will need to be serviced. The applicable errors this article covers are listed below.
- 84404571 – J1: Motor Overcurrent
- 84404572 – J2: Motor Overcurrent
- 84404573 – J3: Motor Overcurrent
- 84404574 – J4: Motor Overcurrent
- 84404575 – J5: Motor Overcurrent
- 84404576 – J6: Motor Overcurrent
- 84404577 – J7: Motor Overcurrent
- 84404578 – J8: Motor Overcurrent
- 844044B1 – J1: Excessive current error
- 844044B2 – J2: Excessive current error
- 844044B3 – J3: Excessive current error
- 844044B4 – J4: Excessive current error
- 844044B5 – J5: Excessive current error
- 844044B6 – J6: Excessive current error
- 844044B7 – J7: Excessive current error
- 844044B8 – J8: Excessive current error
- 84404431 – J1: Driver unit Overcurrent (U-Phase)
- 84404432 – J2: Driver unit Overcurrent (U-Phase)
- 84404433 – J3: Driver unit Overcurrent (U-Phase)
- 84404434 – J4: Driver unit Overcurrent (U-Phase)
- 84404435 – J5: Driver unit Overcurrent (U-Phase)
- 84404436 – J6: Driver unit Overcurrent (U-Phase)
- 84404437 – J7: Driver unit Overcurrent (U-Phase)
- 84404438 – J8: Driver unit Overcurrent (U-Phase)
- 84404441 - J1: Driver unit Overcurrent (V-Phase)
- 84404442 – J2: Driver unit Overcurrent (V-Phase)
- 84404443 – J3: Driver unit Overcurrent (V-Phase)
- 84404444 – J4: Driver unit Overcurrent (V-Phase)
- 84404445 – J5: Driver unit Overcurrent (V-Phase)
- 84404446 – J6: Driver unit Overcurrent (V-Phase)
- 84404447 – J7: Driver unit Overcurrent (V-Phase)
- 84404448 – J8: Driver unit Overcurrent (V-Phase)
Error Description:
Current flow through the motor of the corresponding axis exceeded the permitted value.
The overcurrent error indicates that the robot arm attached to the controller has detected the current needed to drive the joint is in excess of a predefined limit. This error is typically caused by improper setting of the [Mass of payload] setting or by the robot being in contact with an external item such as a safety fence or machine fixture. Whie this error is mostly caused by external factors, it is also possible that a arm can start to brake down over time and start to generate this error due to internal mechanical wear.
Symptoms
Possible Causes and Related Symptoms
- The error codes are applicable for both the RC8 and RC8A series robot controllers. Any series robot is capable of generating an overcurrent error.
- Robot will motor power on but when attempting to jog a certain joint a JX overcurrent error may generate.
- In some cases the error will generate immediately after motor powering on.
- Robot may operate in auto mode for a short period but eventually generate a JX overcurrent error.
- The error may be caused by a number of factors including Arm hardware, Controller hardware, Motor encoder cable issue (the cable which connects the arm and controller) the robot crashing into its workspace, and parameter settings within the robot.
- Other errors are not likely to generate in tandem with the JX overcurrent error.
Possible Causes & Solutions
Possible Remedy:
- Confirm the end of arm load is not in excess of parameter value & arm capacity
- Motor encoder cable broken.
- Robot is not colliding with any external obstacle.
- Driver Unit failure
- Robot internal wiring is damaged
- Mechanical failure of drive component in specified joint
- Motor failure
Tools and Parts Needed:
- Full Sized Teaching Pendant
- #2 Phillips Screwdriver
- Hex Wrench Set
- Before attempting any repairs, please extract a backup project from the controller.
1.Confirm the end of arm load is not in excess of parameter value & arm capacity |
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2.Verify the motor encoder cable is not broken or damaged | Confirm visually. If the cable is damaged, replace the motor encoder cable. |
3.Verify the robot is not colliding with any external obstacle. | Confirm visually. If the arm is in contact with an external item. Jog the robot away from the object and then try to resume operation. |
4.Verify Driver unit card operation. The errors listed below are likely to be caused by Driver Card failure.
| Replace Driver Board with spare driver board, or trade boards within the controller that are the same size. If the error is resolved, or if the error moves to the new Driver Board location, the Driver board is the source of the issue. |
5.Verify no damage to wiring harness inside of robot. | Remove arm covers and confirm visually. If the harness is damaged, please contact Denso for support. |
6.Verify there is no mechanical failure of drive component in specified joint | Release brake of specified joint and move joint by hand. Check for seizing, inconsistent movement or rough movement. If mechanical failure is detected please contact Denso for support |
7.Motor failure | Release brake of specified joint and check for seizing or tightness when moving. |
8.Check controller brake function. | Release and set the brake for the motor and listed for an audible "click". An audible click signifies the controller is sending the brake release signal to the joint in question suggesting the arm is the source. If no audible click is detected the controller may not be supplying the brake release signal to the joint in question. Confirm by measuring the voltage on the 2 yellow wires on the motor power connector. The yellow wires should read 24V when the brake is released. If brake release failure is detected, please contact Denso for support. |
- If the source of the error cannot be determined using the above information, please contact Denso for support. Contact information listed below.
Verification
- If you managed to find and resolve the source of the error the robot should be able to jog through its full motion space without generating the overcurrent error. If the error persists, the arm and/or controller should be swapped out with a spare unit. The damaged equipment should be sent to Denso or one of our certified partner companies
Additional Resources / Related errors
Need More Help ?
- For additional assistance, contact support@densorobotics.com or visit our online contact form at https://www.densorobotics.com/contact/
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