MicroLogix 1400 Series B - RTC resets to UTC

Hi There,

We seem to be having issues with one of our MicroLogix 1400. It appears that after certain days, the RTC time automatically resets to UTC (this happened last Sunday again). This causes issues with our flowmeter reading resets and hours of operation of pumps.
Have we missed any settings which may be causing this issue? Any help will be really appreciated.

Regards,
Anil

Is there a SCADA/HMI system writing to the RTC?

Hi Mickey,
Thanks for your reply, I have checked in the instruction sets as well there are no other system writing to the RTC. I can only see couple of RTC comparisons instructions.
However there is a Grundfos PLC which writes to this PLC (attached Message files, which I am not so much familiar with).
Regards,
Anil

Can you post the program? Zip it first.

You normally can't write directly to the RTC words but there might be an integer being written to and a move instruction writing that to the RTC words.

Zipped file

Hi Mickey,


Please find attached the zipped file, just to inform you the RTC time stays on local time for few days. Last time i updated the code and syncronised the time on 22 Sep 2015 and the RTC reverted back to UTC on Sunday 27 Sep 2015. This is not the first time this has happed, only now we have added the pump control times based on RTC which makes it critical.


Thanks again for your time looking at this, really appreciated.


Regards,
Anil

I'm not at a PC with the software at the moment will take a look later.

Hopefully someone else will.

I don't see anything in the program, but that still does not rule out a SCADA/HMI system or a PC from writing to the RTC.

Is there one connected to the PLC?