1. Field of application and purpose
This manual defines the schedule for technical maintenance of industrial robot controllers (as an example of typical control systems of KRC, IRC and DX series), which are operated on manufacturing enterprises in Ukraine. The procedure covers replacement of cooling filters, inspection and replacement of backup batteries (RTC and CMOS), as well as safe updating of embedded software (microcode).
Regulation developed in accordance with the requirements of norm DSTU EN ISO 10218-1 (Industrial works - Safety) and the standard ISO 13849-1 regarding the safety of control systems. Technical maintenance should be carried out in a planned manner according to operating hours or based on the results of the equipment condition diagnostics.
2. Safety Measures
WARNING! DANGER OF ELECTRICAL SHOCK AND KINETIC ENERGY.
Before starting work, perform a complete lockout/tagout (Lockout/Tagout - LOTO) procedure. Turn off the main input circuit breaker of the controller, lock it with a padlock, and install a warning tag.
PROHIBITED to open the control cabinet while energized. Residual charges on the intermediate loop capacitors of the frequency converter are retained for no less than 5 minutes after turning off the power supply. Check for the absence of voltage with a multimeter on the terminals of the main rectifier before touching internal components.
PERSONAL PROTECTIVE EQUIPMENT (PPE): - Anti-static wristband (ESD protection), connected to a grounded point of the cabinet.
- Protective goggles with side shields (DSTU EN 166).
- Dielectric gloves (class 0, up to 1000 V).
- Non-metallic protective clothing, with protruding elements.
3. Required Tools and Materials
| Tool / Material Name |
Technical specification |
Quantity |
| Torque Wrench |
Range 1.0 – 5.0 Nm |
1 pc. |
| Set of insulated screwdrivers |
Spline (SL) 0.4x2.5, 0.8x4.0; Cross (PH) No. 1, No. 2 |
1 set |
| Digital multimeter |
True RMS, CAT III 1000V / CAT IV 600V (verified) |
1 pc. |
| Anti-static mat and grounding bracelet |
Resistance of the resistor 1 MOhm |
1 set |
| Industrial dust collector with HEPA filter |
ESD safe execution |
1 pc. |
| Air filters for the cabinet |
According to OEM specification (for example, polyester, class G4) |
Kit |
| Backup Battery Packs |
Lithium (Li-SOCl2), 3.6V / 14.4V (OEM spec) |
Kit |
| Certified USB drive |
Formatting FAT32, capacity up to 32 GB (for firmware update) |
1 pc. |
| Woven paper towels and isopropyl alcohol |
Purity not less than 99.4% |
1 package |
4. Pre-inspection Checklist
| Check Element |
Method of inspection |
Acceptance / Rejection Criterion |
Notes |
| Condition of the external seals of the enclosure |
Visual and tactile inspection of doors |
No cracks, breaks, elasticity of rubber preserved |
Provides protection degree IP54/IP55 |
| Ambient Temperature Range |
Measurement with a thermometer near the air intake |
Temperature within the range of +5°C to +45°C |
Above 45°C — critical risk of component wear |
| Presence of errors on the control panel (SmartPad/Teach Pendant) |
System Logbook Report |
Absence of active alarm signals (Error codes) |
Fix previous errors before turning off |
| Integrity of cable entries (hermetic entries) |
Manual torque check and visual inspection |
Cables are not weakened, seals are tightened, no signs of moisture are present |
Prevents dust and lubricant ingress |
| Status of backup batteries in the interface |
Diagnostic menu check |
Voltage of the element above the threshold value (minimum 3.0V for the 3.6V element) |
Warning of discharge appears in advance |
5. Step-by-step procedure for performing the work
- Workplace Preparation and Lockout/Tagout (LOTO)
- Notify the production line operators of the shutdown of the work complex.
- Place the machine in a safe position (maintenance) and turn off the main switch of the controller.
- Install the pendant lock on the power switch and hang the sign «DO NOT TURN ON! People are working».
- Wait 5 minutes for the discharge of the power capacitors inside the enclosure.
Error: Starting work immediately after turning off the automatic circuit breaker results in electric shock on the DC bus (up to 650 V). - Air Filter Replacement and Cleaning for the Controller
- Open the fan protective grilles on the doors or walls of the control cabinet.
- Remove contaminated filter media. Inspect them for the presence of oil stains or metallic dust.
- Use a static-dust vacuum cleaner to remove dust around fan modules and radiators.
- Install new filter mats in accordance with the direction of airflow (the arrow on the filter frame should point into the cabinet).
- Close and secure the fan grilles.
Error: Installing filters backwards restricts airflow, causing the processor board and power supply units to overheat. - Checking and Replacing Backup Batteries
- Attach an anti-static wristband and connect it to a grounded point on the cabinet.
- Find the battery block (usually located on the back panel of the combined CPU board or on the chassis).
- Measure the voltage across the battery terminals using a multimeter (expected value for a new element: 3.6 – 3.7 V for lithium elements, or 14.2 – 14.8 V for assemblies). If the voltage is lower than 3.1 V — the battery is to be replaced immediately.
- CRITICAL: Do not disconnect the old battery connector until reserve power is available or follow the OEM instructions for hot-swap, otherwise the data of absolute encoders will be lost and full zero calibration of the axes will be required.
- Disconnect the old battery connector, install the new battery and securely fasten the connector. Record the installation date on the marking label of the battery.
Error: Long power outage of the motherboard without a backup battery causes loss of CMOS memory and axis calibrations of the robot. - Firmware (System Software) Update Procedure
- Create a full backup (Archive / Backup) of current settings, user programs, and safety configuration to a certified USB storage device. Save the copy on an external company server.
- Check the compatibility of the update version with the operating hardware configuration and peripheral modules of the bus (Profinet, DeviceNet, EtherCAT).
- Insert the USB drive into the service port of the controller or Teach Pendant.
- Launch the update process through the system menu (System -> Software Update -> Install). Follow the instructions on the screen.
- PROHIBITED to turn off power or remove the accumulator during the process of writing files to internal memory (Flash/SSD).
- After completion of installation, perform a controller reboot (Cold start / Power cycle).
- Check the correctness of the system loading, absence of errors, and the operability of the safety interface (Safety controller status).
Error: Interruption of the update process or use of an inappropriate software version causes damage to the bootloader, requiring service intervention and factory reprogramming.
6. Post-repair verification checklist
| Testing / Test |
Expected result |
Actual Result |
Status (Passed / Failed) |
| Leak test and filter installation check |
Filters are installed tightly, no gaps are present, grids are fixed |
|
[ ] Pass / [ ] Fail |
| Voltage measurement on a new battery |
Voltage stable, ≥ 3.6 V (or according to assembly specification) |
|
[ ] Pass / [ ] Fail |
| Temperature control inside the cabinet |
Working temperature of components does not exceed +45°C under load |
|
[ ] Pass / [ ] Fail |
| Safety Chain Testing |
Pressing the emergency stop (E-Stop) button immediately removes the supply voltage (STO) |
|
[ ] Pass / [ ] Fail |
| Axis positioning check |
Deviation at control points (Mastering check) is absent, zero marks coincide |
|
[ ] Pass / [ ] Fail |
7. Troubleshooting and Search Guide
| Symptom |
Likely cause |
Correction action |
| Error "Low Battery Voltage" after replacing the battery |
Poor contact in the connector or installed depleted element |
Check polarity, clean contacts, check voltage with a multimeter. Ensure that the connector is fixed to the click. |
| Controller does not load after software update (black screen or hang on POST) |
File write failure, SSD loader damage |
Perform recovery from a backup system (Recovery USB). In case of critical failure — contact UNITEC-D service support. |
| Overheating of the control cabinet, thermostat trips |
Clogged air filters, cooling fan failure |
Check the rotation of the cooling fans, clean the air ducts, replace the contaminated filter mats with new ones. |
| Encoder error (Encoder Error) after battery replacement |
Loss of power of a high-speed encoder during battery handling |
Perform the procedure of precise zero position calibration of the axes (Mastering / Calibration) according to the robot manufacturer's instructions. |
8. Recommended Technical Maintenance Schedule
| Task |
Periodicity |
Estimated duration |
Personnel Qualification |
Air Filter Inspection and Cleaning/Replacement
Every 1000 hours or 3 months |
0.5 years |
Junior Electromechanic (Qualification 3) |
| Battery status check and voltage |
Every 6 months |
0.5 years |
Automation Engineer (Qualification 4) |
| Full replacement of reserve batteries |
Every 24–36 months (or as signaled) |
1.0 year |
Automation Engineer (Qualification 4) |
| Creation of a full backup (Backup) |
Monthly and before each software update |
0.5 years |
Automation Engineer (Qualification 4) |
| Firmware Update and Cabinet Diagnosis |
For requirements (OEM bulletin issue) |
2.0 – 4.0 years |
Senior Engineer (Qualification 5) |
9. Spare Parts Catalogue
To ensure uninterrupted operation of industrial robots, use original components and high-quality compatible alternatives. Below is a basic list of components for robot controllers:
| Description of the part |
Typical specification |
Category UNITEC |
| Air filter kit for control cabinet |
Size 250x250 mm, class G4, non-flammable |
Control Panel Components / Filtration |
| Lithium battery of the controller (RTC / CMOS) |
3.6V, 2.4Ah, JST connector, Li-SOCl2 |
Electronic Components / Batteries |
| Battery backup module for axes |
14.4V, lithium battery pack with OEM connector |
Electronic Components / Robot Batteries |
| Cooling Cabinet Fan |
24V DC / 230V AC, rolling bearing, IP54 |
Cooling systems / Fans |
Are you looking for original spare parts for industrial robots? Familiarize yourself with the complete range in our electronic catalog UNITEC-D.
10. References to Standards and Documentation
- DSTU EN ISO 10218-1:2019 — Works and Robotics. Safety requirements for industrial robots. Part 1. Robot.
- ISO 13849-1:2023 — Safety of machinery. Details of safety-related control systems.
- IEC 60204-1 — Safety of machinery. Electrical equipment of industrial machinery. Part 1. General requirements.
- Technical documentation from OEM manufacturers (KUKA, ABB, Fanuc, Yaskawa) regarding servicing of controllers series KRC, IRC and DX.
