The perfect checklist to assist with PLC maintenance
Creating and keeping up with a routine maintenance schedule can greatly increase the life of your Programmable Logic Controller (PLC) and greatly decrease the chance of your system malfunctioning. This preventive maintenance should be done as frequently as needed, depending on the controller’s environment — harsher environments will need more frequent maintenance, while more protected environments may not need it as much.
No matter what environment your PLC is in, you should check the system at least quarterly to make sure everything is running smoothly. Check these 13 things for your PLC maintenance routine:
1. Ensure your PLC program is saved
This simple action will ensure that you have a backup just in case the PLC fails. It’s best to have an up-to-date backup, but any fairly recent backup will do. Your saved program can be downloaded onto a new PLC and save you time and money.
2. Check LED indicators
Checking the battery LED indicators can let you know if there are any potential power issues. Check the power and battery indicators to see if they are off or flickering. If so, this may be a sign of low battery or power issues.
3. Replace the battery
When your Battery OK light is on, or even flickering, this means it’s time to change the battery. Losing main control power can create big problems for your system. Avoid this and change the battery regularly; it’s fairly simple and is important to do.
4. Check the operating environment
Your PLC needs to be running in the right conditions to operate optimally. The temperature, humidity, and any potential moisture are all things to check. Clean the filters in the enclosure to ensure quality airflow to help prevent overheating.
5. Check operating voltage
The input voltage that powers your PLC should be in the appropriate range and free from any power spikes or brownout conditions (unintentional drops in voltage).
6. Check program functionality
Ensure that the program, system, and equipment are being controlled as intended. Ensure all is operating as it should be with the system.
7. Check for overheating
Check the CPU and modules for any signs of overheating, including distorted, warped, or discolored cases in addition to any scent of burning.
8. Check venting and clear dust
Dirt and dust that accumulate on the PLC’s components could hinder cooling vents and lead to circuit malfunction. Make sure the module cooling vents are clean and debris-free. Check the electronic boards to make sure no dust is accumulating there as it can cause a short circuit, which could result in permanent damage to the boards.
9. Check connections
All cables, plugs, sockets, terminal strips, wiring, and modules should be connected properly. If your PLC is in an environment that has constant vibrations or other such movement going on, this could loosen connections, so perform this check more often and consider getting a vibration detector.
10. Updates (as necessary)
Keep updated on product notices and upgrades, and update your system as necessary.
11. Clear the area
Your PLC should be free of unnecessary items such as manuals, drawings, or other materials, as they could obstruct air flow and cause the system to overheat due to the creation of hot spots. Over time this could result in a system malfunction.
12. Audit the parts being used
Check each component of the PLC system and see if the parts are in good standing or need replacement.
13. Take inventory of replacement parts
Replacement parts for your PLC should be kept in stock to minimize downtime from a component failure. Already having a spare part in stock during a failure could make your downtown only minutes instead of hours or days. Your PLC is an integral part of your business. By properly performing routine maintenance checks for these 13 things, you can ensure that your PLC is working properly and will work great for years to come. If you need replacement parts to keep in stock or need a PLC part repaired, Qualitrol’s certified technicians can help you out. Check your PLC regularly to prevent failures or malfunctions!