Scheduled Maintenance for Robot Safety Circuits using Kit NXB-KIT-761-008

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Tools Required

• Safety glasses
• Lockout/Tagout (LOTO) kit
• Multimeter
• Precision screwdriver set (flathead and Phillips)
• Wire strippers
• Terminal crimping tool

Article

This document outlines the standard procedure for the 4,000-hour scheduled maintenance of critical safety circuits on NexBot R-20, R-50, C-10, and S-5 series robots. Performing this maintenance is essential for ensuring operational safety, maintaining system integrity, and preventing unscheduled downtime. The procedure utilizes the NexBot Safety 761-008 Multi-Part Maintenance Kit, which contains all necessary genuine replacement components to preserve the validated safety functions of your automation cell.

Failure to perform scheduled maintenance on safety systems can lead to degraded performance, nuisance faults, or a failure of the safety function, posing a significant risk to personnel and equipment.

Schedule

• Interval: This maintenance procedure must be performed every 4,000 hours of robot operation.
• Tracking: Refer to the robot controller's system information screen for the current operational hours.

Parts Needed

All required replacement components are included in the NexBot Safety 761-008 Multi-Part Maintenance Kit.

• Kit SKU: NXB-KIT-761-008
• Kit Contents:
• 1x Replacement Emergency Stop Button (Push-Pull Type)
• 4x Safety I/O Terminal Block Connectors
• 5x Miniature Fuses for Safety PLC (5A)
• 1x Set of Safety Circuit Jumper Wires (Assorted Lengths)
• 1x Terminal Block Labeling Sheet
• 20x Lint-Free Wipes for Connector Cleaning

Procedure

WARNING: This procedure involves working with electrical components inside the robot controller cabinet. Ensure all facility-specific Lockout/Tagout (LOTO) procedures are strictly followed. Only qualified personnel should perform this maintenance.

Step 1: Safety and Preparation

1. Move the robot to its home or a safe maintenance position.
2. Power down the robot controller using the main disconnect.
3. Apply a lock and tag to the main disconnect in accordance with LOTO procedures.
4. Using a calibrated multimeter, verify that there is no voltage present at the main power terminals inside the controller cabinet.
5. Open the controller cabinet door to access the safety PLC and I/O terminal blocks.

Step 2: Replace Emergency Stop Button

1. Locate the primary Emergency Stop (E-Stop) button on the controller or operator panel.
2. Disconnect the wiring from the back of the E-Stop contact block. Note the wire positions.
3. Unscrew the mounting collar and remove the old E-Stop button assembly.
4. Install the new E-Stop button from the kit, ensuring it is securely fastened.
5. Reconnect the wiring to the new contact block, verifying the connections match the original configuration and the robot's electrical schematics.

Step 3: Inspect and Service Safety I/O Terminals

1. Visually inspect all terminal blocks associated with safety I/O (e.g., safety gates, light curtains, E-Stops).
2. Check for signs of discoloration, corrosion, or loose connections.
3. Gently unplug the connectors from the terminal blocks. Use the provided lint-free wipes to clean the contacts on both the male and female sides of the connection.
4. If any terminal block connector shows signs of physical damage or excessive wear, replace it with a new one from the kit.
5. Firmly reseat all connectors.

Step 4: Replace Safety PLC Fuses

1. Locate the safety PLC or safety relay module within the controller cabinet.
2. Identify the fuse holders for the main power or I/O circuits. Refer to the controller's electrical diagram for precise locations.
3. Carefully remove the old fuses. Even if they are not blown, they are replaced as a preventative measure.
4. Install the new 5A miniature fuses from the kit. Ensure they are fully seated in the holders.

Step 5: Inspect Wiring and Update Labels

1. Perform a visual inspection of the wiring connected to the safety circuits. Look for any signs of chafing, cracking, or abrasion.
2. If minor wire damage is found near a terminal, use the provided jumper wires to perform a professional repair as per your facility's electrical standards.
3. Inspect the labels on the safety I/O terminal blocks. If any are faded or missing, use the provided labeling sheet to create and apply new, clear labels.

Verification

1. Ensure all tools and debris are removed from the controller cabinet.
2. Close and secure the cabinet door.
3. Following LOTO procedure, remove the lock and tag and restore power to the robot controller.
4. Power on the controller. Observe the teach pendant for any safety-related alarms. Clear any informational messages.
5. Test the newly installed Emergency Stop button. Press it to confirm the robot's drives de-energize and a corresponding alarm is generated. Pull/twist to reset it and clear the alarm.
6. If other safety devices are present, test their functionality (e.g., open a safety gate to ensure the robot stops).
7. Place the robot in a low-speed manual mode and move each axis briefly to confirm normal operation.
8. Document the completion of the 4,000-hour maintenance in the robot's service log.

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