Hour Meter Reseting

I do this kind of thing on Micrologix systems by using a relatively short interval timer to increment locations in a data file. That way, all you lose is the unexpired time in the timer when the power went down.

You have to be careful with the interval - because of the uncertainty in the start/stop time, you can lose (or is it gain?) a few milliseconds at each tick. By a bit of experimenting, you can adjust for that. I have timers measuring 10 hrs ± about 2 sec.

Send me a private mail if you want more info.

There's probably a way to use the RTO (retentive timer) instruction, but I've not played with it.

I never lost anything with battery back-up. What am I missing here?

James

In AB speak, most types of timer & counter instruction reset the accumulator when you power down.

As I kinda suggested, stashing the current time or count in "ordinary" memory (which is retentive) ensures that it's saved; also there is a retentive timer instruction which doesn't reset over power cycling.