Micrologix RTC problem

On the Micrologix 1100, I'm having an issue with RTC freezing. I think its only happening after a power outage. But when I go to enter values into the RTC, it causes a fault. The only way I can unlock it is to go to the RTC online and press the set date and time. My computer will write to the RTC then I can go back and write to it from my HMI. Is the battery backup bad?

Can you write to the RTC using the CPW instruction from the PLC program?
CPW #N7:0 #RTC:0.HR 1

Then the computer or screen can set the correct time.

Just a thought,

Normally, there is no problem. That's exactly how I have it set up. But it appears that there was a power outage at the site and after that, when the time is entered via a touch screen using the CPW command, it triggers a fault. I went online with my computer and reset the RTC. After that, it worked again. Something about the power outage caused the issue.

You might want to check the value from the HMI for limits before the copy instruction.

What is the fault?

RTC Issues

The fault said write error to RTC. When I went to the RTC, all the values had gone to 0. That's why I'm thinking there is something up with the back up battery. But the controller is hardly a year old.