In order to the get most life out of your GE 90-70 series PLC system we’re going to start with the basics: the controls themselves. It pays to know your hardware.
In addition to the manufacturer’s recommended PM schedule, we’ve found that there are some simple steps that help alleviate a lot of headaches.
Stock up on Spare PLC Parts
PLCs are tough, and often seem like they can last forever. Inevitably, though, some component is going to fail, and the quickest solution is to simply replace the part. GE recommends that you keep one of each component, or 1% – whichever number is higher – on hand for quick replacement.
We’ve found there are a couple of components that we know are going to wear out pretty consistently. For these, it’s worth your while to schedule swapping them before they go bad.
PLC Processor Batteries
The batteries that power the processors in the PLCs are not rechargeable, and will need to be replaced every two to three years. The lifespan of the batteries can be affected negatively by both the age of the system and the temperature they’re subjected to, so take into account your system when scheduling a time to swap them out.
And we do strongly recommend replacing them before they fail. Although a system can continue to operate with a bad battery, if a power outage occurs, the programming will be wiped out. That leaves you looking for backups and the system likely out of service beyond the outage.
If you’re ready to change your existing batteries but need a little guidance, we’ve produced a video you can watch here.
PLC Power Supplies
Along with your output modules, power supplies are the hardest working parts of your system. And like the processor batteries, you can count on them needing to be replaced on a regular schedule. We recommend changing out the power supplies every five years, especially in environments where it’s hot.
Due to their hard-working status, it’s best to keep extra power supply units on hand – even above the minimum “one of each” recommendation.
Additional Considerations for Your PLC System
Any part of your system that drives current or builds up heat is going to be at high risk of failure. Be ready with these components already on hand. Since output modules are also heavy lifters, keep extras of them as well.
You can get by with the minimum recommendations for on-hand stock with input modules, as they don’t draw a lot of power and are fairly hard to kill.
Scheduled Maintenance of PLCs
Sure, everyone knows how important that PM schedule is. Yet, neglected maintenance tasks are easily the number one missed opportunity to find problems in the system before they become a major issue.
So we’re going to harp on it for just a bit. Bear with us.
In our capacity as the only authorized GE repair facility and the go-to service for GE 90-70 PLC troubleshooting and on-site assistance, we see a lot.
And we can tell you that staying on top of your entire PM schedule is incredibly critical. The more you put off PM the more trouble you are going to have in the future. It’s simply not worth it; for your mental well being or your wallet.