S5 remanent memory deleted

Hi,
Last night there was a problem with an S5 PLC, don't now what just happened but the failure we got in U-stack & B-stack was 'REMAN : = Alle zeiten /zahler/merker geloescht 1 = nur 2 haelfte z/z/m' so it seems that all timers, counters and flags where deleted. Does anyone know what could cause such an error?
Thanks

Heino,

the timers, counters and flags are not 'deleted', but 'reset'. Ther's a big difference between these two terms. Secondly, the text 'REMAN : = Alle zeiten /zahler/merker geloescht 1 = nur 2 haelfte z/z/m' tells you that only the first half of all timers, counters and flags were retentive to start with, the second half is never retentive. This is a situation common to the S5-115U series. These settings are related to the bottom switch on the front of the CPU. It has three markings:

1. NR or Non-Retentive: the PLC has no retentive timers, counters and flags.
2. RE or REtentive: the first half of all timers, counters and flags are retentive, the others ain't.
3. OR or Overall Reset. This could well be that somebody (accidently or not) used this setting. Normally putting the switch to this setting does nothing, but if you switch the RUN-STOP switch twice from STOP to RUN while you're holding the bottom switch in the OR position, then the entire memory gets erased.

So, to me, the most likely thing that happened to your installation is that somebody has put the bottom switch in the NR position and then power has failed.

Kind regards,