Eaton XC200 Series User Manual

10/10 MN05003004Z-EN Data remanence41Data remanenceThe controller has a memory area for remanent data a page 10.The variables declared with “VAR_RETAIN” are saved in this areaand are thus retentive during a warm start of the applicationprogram (Caution: This does not apply for I, Q and M variables!).Data that are remanent for a cold start – “VAR_RETAINPersistent” are not supported. Remanence (non-volatility) of thedata is guaranteed when the PLC is switched off if a battery isinserted.If it was not possible to finish a cycle that was being processed,because of a supply interruption, then the data will not beconsistent, since the interruption could have occurred at any pointof the cycle. When the voltage supply recovers, the residual-cyclewill not be completed. The control starts according to the set startbehaviour.If this is to be prevented, appropriate measures must be taken aspart of the engineering. One solution for this problem is anuninterruptible power supply with additional accumulatorbuffering.Program transferThe transfer of an application program always takes place via thebattery-buffered SRAM area in the controller. Afterwards, abackup can be created on the multimedia card by using the“Create boot project” command. A program backup can only becreated while the system is in the “HALT” state. The internalFLASH memory of the CPU cant be used as storage for a programbackup.Operating statesIn the following overview you will find the state definitions ofXC100. The LED-displays of the corresponding states are alsodetailed..State Display DefinitionRUN/STOP SFSystem test off off System test inprogressSystem update on on System update inprogressSwitch-on OK off off System test finishedwithout errorSwitch-on not OK blinks blinks System test generatedan errorNOT READY off on No applicationprogram presentSTOP blinks off Application programloaded, PLC in“STOP” stateRUN on off Application programloaded, PLC in “RUN”stateSTOP/RUN withgeneral error,diagnosismessageon on General error/diagnosis messageavailable