Troubleshooting Error E-1015: Axis Drive Power Fault on NexBot R-20, R-50, and S-5 Series Robots

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Tools Required

• Lockout/Tagout (LOTO) kit
• Calibrated torque wrench
• Appropriate size socket/wrench for connectors
• Multimeter with insulation test function (or Megohmmeter)
• Safety glasses
• Isopropyl alcohol and lint-free swabs

Article

This article provides troubleshooting guidance for the error code E-1015 (Axis Drive Power Fault) on NexBot R-20, R-50, and S-5 series articulated robots. This fault typically points to an interruption in the power supply between the servo drive amplifier and a specific joint motor. A common cause is a fault with the motor power cable, specifically the NexBot Vision PWR511-003 Motor Power Cable (SKU: NXB-SRV-PWR511-003).

Following these steps can help maintenance personnel identify the root cause and restore the system to operational status.

Symptom

When this fault occurs, the operator will typically observe the following:

• The error message "E-1015: Axis Drive Power Fault" is displayed on the robot teach pendant, often specifying which axis is affected (e.g., J1, J2, etc.).
• The affected robot axis may go limp as the motor brake engages and drive power is lost.
• The robot stops its current program and enters a faulted state.
• The status indicator on the corresponding servo amplifier in the controller cabinet may show a fault light (typically red or amber).

Cause

The E-1015 fault can be traced to several potential issues with the motor power cable (NXB-SRV-PWR511-003). The most common causes include:

1. Loose Connectors: The M-type connectors at either the controller cabinet or the robot joint motor have loosened due to vibration, resulting in an intermittent or open connection.
2. Cable Damage: The cable's outer jacket or internal conductors are damaged from abrasion against machine surfaces, pinching in axis housings, or exceeding the minimum bend radius during robot motion.
3. Connector Contamination: The connector pins are contaminated with oil, coolant, or metallic debris, causing a high-resistance connection or a short circuit.
4. Internal Conductor Failure: One or more power conductors inside the cable have broken due to metal fatigue from repetitive motion.
5. Improper Installation: The connectors were not torqued to the correct specification during a previous installation or maintenance activity, leading to a poor connection.

Resolution Steps

WARNING: This procedure involves hazardous voltages (400VAC). Only qualified personnel who have completed all required safety training should perform these steps. Always follow your facility's Lockout/Tagout (LOTO) procedures.

1. Safety First: Perform a full LOTO procedure on the robot controller cabinet to de-energize the system completely. Verify that all stored energy has been dissipated.
2. Identify the Affected Cable: Using the error message on the teach pendant, identify the specific joint axis that is faulting. Locate the corresponding NXB-SRV-PWR511-003 motor power cable that runs to that joint motor.
3. Visual Inspection: Carefully inspect the entire 3-meter length of the identified cable. Look for signs of pinching, abrasion, cuts, or heat damage. Pay close attention to areas where the cable flexes or passes through tight channels.
4. Connector Inspection:

• Disconnect the cable's circular connector from the motor at the robot joint.
• Disconnect the corresponding connector at the servo amplifier inside the controller cabinet.
• Inspect the pins and sockets on both the cable and the mating receptacles. Look for bent or broken pins, signs of arcing (black marks), or contamination. Clean the connectors with isopropyl alcohol and a lint-free swab if necessary.

1. Electrical Testing (Requires Multimeter):

• Continuity Test: Set your multimeter to the continuity or resistance setting. Test for continuity between the corresponding pins at each end of the cable (e.g., pin A to pin A, pin B to pin B, etc.). An open circuit (infinite resistance) indicates a broken internal wire.
• Insulation Test: Set your multimeter or megohmmeter to the insulation test setting. Test for shorts between each power conductor and the connector's ground shell. Also, test for shorts between the individual power conductors (e.g., Phase U to Phase V). Any reading other than infinite resistance indicates an internal short circuit.

1. Reseat and Torque Connectors: If the visual inspection and electrical tests pass, securely reconnect the cable at both the motor and controller ends. Use a calibrated torque wrench to tighten the connector collars to the specified 3 Nm. An improper torque value can lead to connection issues.
2. Cable Replacement: If any part of the inspection or testing fails (visible damage, failed continuity, or shorts), the cable must be replaced. Order a new NXB-SRV-PWR511-003 cable. Ensure the new cable is routed correctly, avoiding pinch points and respecting the minimum bend radius.
3. Verification: After completing the steps, remove the LOTO devices and power on the robot controller. Clear the fault from the teach pendant. Carefully jog the affected axis at a low speed to confirm that it is functioning correctly. Run a test program to verify full operational recovery.

Prevention

To minimize the recurrence of this fault, implement the following best practices:

• During routine maintenance, visually inspect all motor power cables for wear and ensure they are properly secured within their cable management tracks.
• Verify that all connector collars are torqued to the specified 3 Nm.
• Ensure that the robot's programmed movements do not cause the cable to bend tighter than its specified minimum bend radius or to rub against abrasive surfaces.
• Keep the area around the robot free of debris and fluid leaks that could contaminate connectors.

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