GSV Walltimeclock Retentive?

I am currently working on a refinery site and looking at an ongoing issue regarding a loss of data after power loss to a Contrologix 5562 Processor. These are gas usage totaliser readings returning to zero. Inside the code the totalisers are reset when the PLCTime variable is set to midnight each day and yearly totaliser on the new years eve at midnight (Year 1, Month 1, Day 1, Hour 0, Minute 0. The PLCTime is produced by a GSV Walltimeclock function, this is in the main routine.

I know that variables should be retained after a power loss, but i wasn't sure how this dealt with the GSV Walltimeclock. Is it correct to think for the first scan this would default to Year 1, Month 1, Day 1, Hour 0, Minute 0, Second 0, mS 0. If this is the case is there a way around this??

I made a simple program using the GSV and Compare instructions to latch bits if Localtime[n] was equal to zero. I used year, month, day, hour and minute. The only way I was able to make bits latch was to remove the battery from the plc. Of course this required to download the project after power up. When I did this the hour bit latched and WallClocktime defaulted to 1/1/1998 00:00

No bits latched with battery in place and cycle of power. The time was retained.

S:FS is the first scan bit in RS5K. Search for that to see if the first scan resets your values.

good luck with your project and Welcome to the Forum.

edit: program was done on L5562 version 18

Welcome to the Forum !

Is it correct to think for the first scan this would default to Year 1, Month 1, Day 1, Hour 0, Minute 0, Second 0, mS 0

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This is only true if the controller battery is dead or disconnected, and the main power has been cycled.

I agree that a powerup routine of something conditioned on the S:FS first scan bit is probably resetting this logic. Also check to be sure that nobody is running the "Logix 5000 Clock Sync Utility" on a misconfigured computer.