Problem with the date in a ControlLogix 1756-L62 and its battery

[acortes]

I have a Allen Bradley Control Logix 1756-L62, and we have an applicattion that takes the time from the PLC. Since a couple of weeks, we have the trouble that the time in the PLC(I check it with RSLogix) it doesn´t match with the real time, and i need to reconfigure it 2 times at day.

It seems like when the PLC lost its power, only lost the hour, not the date (For example: 10/11/2010 8:00pm changes to ----->10/11/2010 11:00am)

Is there a problem with the battery? or Could be another kind of problem?

regards...

 

[Gil47]

Does the time always take a 9 hour step backwards

My wild guess is


That you have a PC or another PLC that sets the master time on this PLC and maybe others at a set time interval say every 6 hours.

That PC was given an AM time when it should have had a PM time and then day light saving has stepped the PC one hour.

 

[daba]

If there was a problem with the battery, and it was unable to keep the PLC clock going, then the BATT light on the front of the processor would be on, and you would lose the whole program and data when the power goes off.

Do a search for SSV instructions to see if the date/time is being set from external data. It could look like either of the instructions below....

 

[nightline]

What are the settings in the controller properties tab Time/date ?

 

[rdrast]

I run the Logix5000 Clock Update Tool on one server here to perform scheduled updates to all of our Control/CompactLogix processors. Is it possible someone there is running that tool on a PC with a bad time reference?

 

[acortes]

Hello again¡ Thanks for the answers, all were really helpful. Right now, the problem is solved.
All was about the reference time that the PLC takes in their register of WallClockTime. The Control Logix takes the reference of time of the GMT (taken from the controller properties tab time/date).
I tried several times, change the time in this tab. But I was using my time (Mexico Time). That´s the reason for the time most commonly was 7 o 8 hours step backwards.

To fix the problem, I set the time with the GMT.

Regards

 

[Operaghost]

Check the logic where you are reading the time (look for GSV instruction). The parameter you want is LocalDateTime instead of DateTime. LocalDateTime is adjusted by timezone and optionally by daylight savings.

OG