1. Purpose and Purpose
This practical guide is designed for maintenance technicians and focuses on the essential procedures for managing industrial robot controllers. The goal is to ensure operational continuity, reliability and longevity of robotic systems, preventing unplanned downtime and ensuring constant performance. The guide covers the most popular controller models in the machine tool building industry, including principles applicable to series such as ABB IRC5, KUKA KRC4 and FANUC R-30iB.
The maintenance described includes three critical aspects: replacing the cooling fan filters, checking and possibly replacing the memory backup battery, and performing firmware updates. These activities, when performed regularly and accurately, help keep the controller within optimal operating parameters, protecting your investment and maximizing productivity.
2. Safety Precautions
ATTENTION: Carrying out the procedures described requires maximum caution and strict compliance with current safety regulations (e.g. UNI EN ISO 10218-2). Failure to comply may cause serious injury to personnel, damage to equipment and production interruptions.
- BLOCK/LABELING (LOTO): Before any intervention, ensure that the controller is completely de-energized and that the Lockout/Labeling procedure has been applied in accordance with the UNI EN directive ISO 14118 to prevent accidental restarts or unexpected power supply dangerous.
- PERSONAL PROTECTIVE EQUIPMENT (PPE): Always wear safety glasses compliant with regulation EN 166, certified insulating gloves EN 60903 for electrical work (where appropriate), and EN safety footwear ISO 20345.
- ELECTRICAL DANGERS: Robot controllers operate with high voltages (e.g. 400V AC, 24V DC). Make sure you have verified the absence of voltage with a certified multimeter (CAT III 1000V) before touching any internal components. Pay attention to the residual discharges present in the capacitors.
- MECHANICAL HAZARDS: If the power supply to the controller has not been fully isolated, there is a risk of unexpected movement of the robotic arm. Always check that the robot is at a safe standstill and that all axes are blocked.
- FIRE RISK: Backup batteries may contain flammable substances. Handle them with care and avoid short circuits. Make sure there are appropriate fire extinguishers (class C) nearby.
3. Tools and Materials Required
To perform maintenance tasks, prepare the following tools and materials:
| Tool/Material | Specify | Quantity |
|---|---|---|
| Digital Multimeter | CAT III 1000V, with DC and AC voltage measurement function | 1 |
| Torque wrench | Torque range 5-50 Nm, accuracy ±4% | 1 |
| Torx Screwdriver Set | T15, T20, T25, T30 | 1st Sep |
| Hex Key Set (Sockets) | Measurements from 5mm to 10mm | 1st Sep |
| Industrial vacuum cleaner | With HEPA filter, for fine dust | 1 |
| Antistatic cloth | In microfibre, without fibres | 2-3 |
| Spray for Electronic Contacts | Non-conductive, rapidly evaporating | 1 can |
| Replacement Fan Filters | Specific for controller model (e.g. G4 EN 779, 200x200x22 mm) | 2-4 (depending on model) |
| Backup battery | Specific to controller model (e.g. Lithium 3.6V, 2000mAh, or NiMH 2.4V) | 1 |
| USB drive | Minimum 8GB, with OEM certified firmware | 1 |
| Laptop PC | With diagnostic software and connection cables (Ethernet/USB) | 1 |
4. Pre-Maintenance Inspection Checklist
Before starting any work, carry out a detailed visual and functional inspection of the robot controller. Record all findings.
| Item | Control | Acceptance/Rejection Criteria | Notes |
|---|---|---|---|
| External Cabinet | Check for dents, deep scratches, signs of corrosion or infiltrations | No structural damage, visible corrosion, signs of liquids | |
| Door seals | Visually inspect gaskets for cracks, hardening or missing sections | Seals intact, elastic, without interruptions; no dust or humidity inside | IP protection compromised if damaged |
| Cooling Fans | Listen to the noise during operation; check outgoing air flow | Absence of abnormal noises (squeaking, excessive buzzing); constant and vigorous airflow | Abnormal noises indicate worn bearings or unbalanced blades |
| LED indicators | Check the status of the LED indicators on the front or internal panel | All status LEDs in green (or color indicated by the OEM manual as normal); no active alarm LED | Active alarm LEDs indicate a pre-existing problem |
| Internal Ambient Temperature | Use infrared thermometer to measure temperature on display or inside cabinet (if safely accessible) | Temperature ≤ 40°C (104°F) | High temperatures can shorten the life of electronic components |
| Internal Cleaning (Visual) | Visually inspect electronic components for dust, debris, cobwebs, or condensation | Clean interior, no significant accumulations of dust or contaminants | Dust can act as a thermal insulator and cause short circuits |
| Internal Wiring | Visually check for loose, damaged, frayed, or compromised insulation wires | Cables intact, well secured, without sharp bends or signs of overheating | Damaged wiring can cause signal interruptions or short circuits |
5. Step-by-Step Procedure
5.1. Preparation and Safety
- Robot deactivation: Place the robot in a safety configuration ('Home' or 'Parking' position) and deactivate all drives.
- Energy Isolation: Proceed with complete disconnection of the robot controller. Open the main power switch and apply the Lockout/Labeling (LOTO) procedure on the main energy source (e.g. isolation switch in the electrical panel), according to the UNI EN ISO 14118. standard
- Verify Absence of Voltage: Use a digital multimeter (CAT III 1000V) to verify the absence of voltage on all access points to the controller (e.g. power terminals, internal busbars). Common mistake: Relying only on the controller's indicator lights. Always check with a multimeter.
- Wear PPE: Make sure you wear all the required Personal Protective Equipment: safety glasses, gloves and safety shoes.
5.2. Replacing Fan Filters
- Accessing Filters: Locate the panels or doors that house the fan filters on the controller cabinet. You may need to use a Torx screwdriver (e.g. T20) to remove the retaining screws.
- Removing Old Filters: Carefully remove used filters. If the filters are very clogged, be careful not to disperse the dust into the environment or inside the controller.
- Cleaning Grilles and Housings: Use an industrial vacuum cleaner with a HEPA filter to carefully remove dust and debris from the ventilation grilles and filter housings. You can use compressed air for hard-to-reach areas, but be sure not to direct the flow directly at electronic components and vacuum up any expelled dust.
- Installing New Filters: Insert the new filters, ensuring they are oriented correctly (usually indicated by an arrow on the filter indicating the direction of airflow). Make sure the filters are of the type and size specified by the OEM (e.g. G4 EN 779, 200x200x22 mm).
- Re-fixing Panels: Reposition and fix the panels or filter doors. Tighten the screws with a torque of 2.5 Nm. Common mistake: mounting the filters upside down, compromising cooling efficiency.
5.3. Checking and Replacing the Backup Battery
- Battery Location: Open the controller cabinet (if necessary, with a T25 Torx screwdriver) and locate the backup battery module. Its location varies depending on the controller model (often on the motherboard, memory module, or a separate drive).
- Measure Battery Voltage: With the digital multimeter set to 'V DC', measure the voltage across the battery. A voltage below 2.8V for 3.6V batteries (or proportional for other types, e.g. <2.0V for 2.4V batteries) indicates that the battery is low and needs to be replaced. Critical voltage for a complete cycle: < 2.2V per batterie al litio 3.6V.
- Battery Replacement (if necessary):
- Gently disconnect the old battery connector from its slot on the board.
- Remove the used battery. Dispose of the old battery according to local regulations (WEEE).
- Insert the new battery (e.g. lithium 3.6V, 2000mAh) making sure of the correct polarity.
- Reconnect the connector. Tighten any battery module fixing screws with a torque of 0.8 Nm.
- Check Battery LED Status: Some controllers have a LED dedicated to the battery status. Check that, after replacement, this LED indicates an 'OK' status (usually green).
5.4. Firmware update
- Preparing USB Drive: Load the latest firmware file (obtained from the OEM manufacturer) onto a USB drive formatted in FAT32. Make sure the file is not corrupt and that it exactly matches the controller model.
- USB Drive Connection: Insert the USB drive into the appropriate port on the controller (usually front or internal, indicated as 'USB Service').
- Access Service Mode: Turn on the controller. Enter the system menu or maintenance/service mode. The exact procedure varies for each OEM (e.g. by pressing specific keys during startup, or via HMI). Refer to the manufacturer's manual.
- Firmware File Selection: From the service menu, navigate to the 'Firmware Update' or 'System Update' option and select the firmware file from the USB stick.
- Start Update: Confirm the start of the update procedure. CAUTION: Never turn off power to the controller while updating the firmware. This can make the controller unusable.
- Completion and Restart: Wait for the update to complete and the controller to automatically restart. The process can take 10 to 30 minutes.
- Check Firmware Version: After rebooting, access the 'System Information' or 'Versions' menu to check that the firmware version has been correctly updated.
5.5. Re-assembly and Initial Testing
- Closing Cabinet: Close all doors and panels of the controller. Make sure that the gaskets are correctly positioned and that all screws (e.g. Torx T25) are tightened to the specified torque (e.g. 2.5 Nm for external panels).
- Reconnect Power: Remove the lockout/tagout and restore power to the controller.
- Start Controller: Turn on the robot controller. Carefully monitor the startup sequence, checking for any error messages or alarms on the operator panel or HMI.
- Robot Functional Test: Perform a short robot movement test (e.g. manual 'jog' of each axis) to verify correct operation. Make sure that the movements are fluid and without hitches or abnormal noises.
6. Post-Maintenance Verification Checklist
After completing maintenance, perform the following checklist to confirm successful restoration of controller functionality.
| Test | Expected Result | Actual Result | Result (Pass/Fail) |
|---|---|---|---|
| Controller startup | Completed without errors or alarms on the operator panel | ||
| Firmware version | Corresponds to the version installed during the update | ||
| Fan noise | Normal, air flow perceivable from the grilles, no vibrations | ||
| LED indicators | All status LEDs green (or 'OK' status according to OEM manual) | ||
| Robot Movement Test (Jog) | Smooth and controlled movements on all axes, no drive alarms | ||
| Access to Programs | Loading and running a robot test program (if applicable) |
7. Troubleshooting Guide
This section provides a quick reference for common problems that may arise after servicing the robot controller.
| Symptom | Probable Cause | Corrective Action |
|---|---|---|
| 'Fan Malfunction' or Overheating alarm | Clogged fan filters, faulty fan, excessive ambient temperature | Clean or replace the filters. Check and replace the fan if faulty. Ensure an ambient temperature below 40°C. |
| Loss of Configuration Data after Reboot | Backup battery discharged or faulty, battery connection interrupted | Replace the backup battery. Check the correct battery connection. |
| Firmware Update Failed or System Error | Corrupt or incompatible firmware file, power failure during update, faulty USB drive | Check the integrity and compatibility of the firmware file. Repeat the procedure with another USB drive. If the error persists, contact OEM technical support. |
| Controller Does Not Start or Stops | Loose or incorrect cable connections, faulty hardware component, power problems | Check all internal wiring. Retry startup. Check the power supply voltage. |
| Abnormal noises from the fans after replacing the filters | Filters installed incorrectly or not original, fan unbalanced or at the end of its life | Check the correct positioning of the filters. Replace the fan if the noises persist. |
8. Recommended Maintenance Schedule
An effective preventative maintenance program is critical to maximum controller reliability.
| Activities | Frequency | Estimated Duration | Level of Competence |
|---|---|---|---|
| General Visual Inspection | Weekly | 15 min | Operator / Technician |
| Cleaning Fan Filters | Monthly | 30 min | Technical |
| Replacing Fan Filters | Semi-annually (or based on operating environment) | 45 min | Technical |
| Check Backup Battery Voltage | Annual | 30 min | Specialized Technician |
| Backup Battery Replacement | Every 3-5 years (or if critical voltage) | 45 min | Specialized Technician |
| Firmware update | Upon OEM indication (typically annual or for new features/security patches) | 1-2 hours | Specialized Technician |
| Wiring and Connection Inspection | Annual | 1 hour | Specialized Technician |
9. Spare parts reference
The use of original or equivalent quality spare parts is critical to maintaining the performance and reliability of the robotic controller. Below is an indicative list of common spare parts.
| Part Description | Typical Specification | UNITEC category |
|---|---|---|
| Air Filter for Fan | Material G4 according to EN 779, ISO Class Coarse 65% according to ISO 16890. Variable dimensions (e.g. 200x200x22 mm) | Ventilation Components |
| Backup Battery (Li-Ion) | Lithium-Ion, 3.6V DC, Capacity 2000-2600 mAh. Specific OEM connector. | Controller power supply |
| Backup Battery (NiMH) | Nickel-Metal Hydride, 2.4V DC, Capacity 1000-1500 mAh. Specific OEM connector. | Controller power supply |
| Cooling Fan | 24V DC, with speed sensor (PWM), variable dimensions (e.g. 120x120x38 mm), minimum flow rate 150 CFM. | Ventilation Components |
| Industrial USB Memory Drive | 8GB or more capacity, USB 2.0/3.0 interface, resistance to industrial vibrations and temperatures. | Control Accessories |
| Shielded Ethernet Cable | Category 6a (Cat6a) or higher, SFTP shielding, PVC/LSZH sheath. Variable length. | Cables and Connectors |
For the supply of high quality original and compatible spare parts, consult our online catalogue: www.unitecd.com/e-catalog/
10. References
- UNI EN ISO 10218-2: Robots and robotic equipment - Safety requirements for industrial robots - Part 2: Robotic systems and integration.
- UNI EN ISO 14118: Machinery safety - Prevention of unexpected starting.
- CEI regulations: Guide to protection against indirect and direct contacts in electrical systems.
- Operation and Maintenance Manual of the Robot Controller Manufacturer (e.g. ABB, KUKA, FANUC).
- Machinery Directive 2006/42/EC.
