Intermittent DC Bus Under-Voltage Fault on R-20 with NXB-CBL-512-001 Cable

Description

We are experiencing intermittent shutdowns on our R-20 series robot, which is used in a pick-and-place application. The controller is logging an 'E-2103: DC Bus Under-Voltage' error. The fault occurs randomly, but seems more frequent when the arm is performing rapid, high-extension movements. We have verified the main power supply is stable at 48.5VDC. The problem seems to be related to the power delivery to the robot base. We are using the specified NexBot Robotics NXB-CBL-512-001 Bus Power Cable, which was installed about 18 months ago. Wiggling the cable near the connector at the robot base sometimes temporarily clears the fault, leading us to suspect an internal break in the cable itself despite its high-flex rating. The production line is currently stopped, and we need to identify the root cause urgently.

Symptoms

• Robot arm halts unexpectedly during operation.
• Controller logs a recurring DC Bus Under-Voltage error (E-2103).
• Fault is more prevalent during high-acceleration or full-extension movements.
• Manipulating the NXB-CBL-512-001 cable near the robot base connector can induce or clear the fault.

Resolution

The customer was guided through diagnostic steps to confirm the integrity of the NXB-CBL-512-001 cable. A continuity test performed with a multimeter while flexing the cable revealed an intermittent open circuit on one of the 48VDC conductors. The repeated stress from the robot's motion cycle had caused an internal wire to fracture near the overmolded M12 connector. Replacing the faulty NXB-CBL-512-001 with a new unit restored stable power to the robot arm and permanently cleared the E-2103 under-voltage error. The robot has been running without interruption for 24 hours post-replacement.

Resolution Steps

1. Safely power down the robot controller and apply Lockout/Tagout procedures.
2. Disconnect both ends of the suspect NXB-CBL-512-001 cable.
3. Set a digital multimeter to the continuity test setting (audible beep).
4. Test continuity on each corresponding pin from one end of the cable to the other.
5. While testing the main power pins, gently bend and manipulate the cable along its length, paying close attention to the area behind the connectors.
6. Confirm the intermittent break when the cable is flexed in a specific direction.
7. Replace the identified faulty cable with a new NXB-CBL-512-001.
8. Power on the system and run a test routine to confirm the fault is resolved.