1. Content and purpose
This technical manual is intended for performing battery replacement and program saving in programmable logic controllers (PLCs) used in industrial systems. Battery replacement is necessary to keep the PLC operational in the event of battery failure, and program retention ensures continuous system operation after power is restored. This manual is intended for repair technicians, production service managers, and reliability engineers.
2. Network security measures
Any work with the PLC must be done in compliance with safety regulations, including blocking and attaching power.
Before starting work with the PLC, take the following safety measures:
- Turn off the PLC and system power.
- Use electrical protective gloves, goggles and protective clothing.
- Perform blocking and energy attachment using blocking and tagging tools.
- Make sure that there are no electrical loads on the device.
3. Tools and materials
| Name of the tool | Specification | Quantity |
|---|---|---|
| Screw wrench | The range is 4–30 Nm | 1 |
| Multimeter | Range 0–20 V, 0–200 Ohm | 1 |
| Compact cable stand | The size is 100 mm | 1 |
| AA 1.5 V battery | 1.5 V, 2500 mAh | 1 |
| Optical meter | The range is 0–100 mm | 1 |
4. Inspection before service
| Point | Verification | Acceptance/rejection criteria | Notes |
|---|---|---|---|
| 1 | Turn off the power | The reading of the power supply device is 0 V | Use a multimeter |
| 2 | Check the absence of voltage | Measure the voltage on all cables | Use a multimeter |
| 3 | Check the battery status | Battery voltage > 1.2 V | Use a multimeter |
| 4 | Check the condition of the cables | No wear and tear | Use an optical meter |
5. Passportized steps of the procedure
- Power off
Perform a complete power off of the PLC and the system. Use a multimeter to check for no voltage. Disconnect the power supply at the input switchboard.
Error: Power off failed, which may cause malfunction or injury. - Removing the old battery
Open the PLC case using the wrench. Remove the old battery paying attention to the electrical connections. Check the contacts for wear.
Error: Opening the case without turning off the power may cause malfunction or injury. - Replacing a new battery
Insert the new battery into the appropriate slot. Check that the voltage (1.5 V) and size (2500 mA·h) match. Use a multimeter to check the voltage.
Error: Using the wrong type of battery can cause malfunctions or impaired performance. - Saving the PLC program
Download the PLC program to an external medium (for example, a USB flash drive). Use the software to save the program. Check if the saved program is displayed on the screen.
Error: Improperly saving the program may result in data loss or malfunction. - Checking the operation of the PLC
Return the power to the PLC. Use a multimeter to check the voltage on all cables. Check whether the PLC is working properly.
Error: Failure to check the operation of the PLC may lead to a lack of system functionality.
6. After service check
| Test | Expected result | Actual result | Pass/Fail |
|---|---|---|---|
| 1 | Voltage on input cables | 0 V | Pass/Fail |
| 2 | Battery voltage | 1.5 V | Pass/Fail |
| 3 | PLC work | It works without any problems | Pass/Fail |
7. Recommended ways to solve problems
| Symptom | A possible reason | Actions to resolve |
|---|---|---|
| The PLC does not turn on | Lack of power | Check the power and perform the lockout |
| The PLC program is lost | Save error | Check the program save |
| Case opening error | Invalid key | Use the correct key |
8. Recommended maintenance schedule
| The task | Frequency | Continuity | Skill level |
|---|---|---|---|
| Replacing the battery | Annually | 30 min | Average |
| Save the program | Annually | 45 min | Average |
| PLC operation check | Annually | 60 min | Tall |
9. Special components
| Description of the component | Typical specification | UNITEC-D category |
|---|---|---|
| AA 1.5 V battery | 1.5 V, 2500 mAh | Category 250 |
| Cable for PLC | Specialized for PLC | Category 300 |
| Screw wrench | The range is 4–30 Nm | Category 150 |
| Multimeter | 0–20 V, 0–200 Ohm | Category 200 |
10. Links
This manual complies with EN 60204-1, ISO 13849-1, DSTU 4608:2011, and the requirements of PLC manufacturers such as Siemens, Allen-Bradley, and Omron.
