Grabbing persistence value not working

Add-ons Persistence Services
1

I’m trying to grab the latest value of an item, but I keep getting an error. Tried it with different iterms, they all have values in the db.

part of .rules
logInfo("Meterstanden", MeterElekDag.lastUpdate)
logInfo("Meterstanden", MeterElekDag.previousState)

log message
2017-11-03 10:08:00.884 [ERROR] [.script.engine.ScriptExecutionThread] - Rule 'Load meterstanden': An error occurred during the script execution: Could not invoke method: org.eclipse.smarthome.model.script.actions.LogAction.logInfo(java.lang.String,java.lang.String,java.lang.Object[]) on instance: null

I also trued it with sendCommand, but het the same message.
If I understand it well, it reports that there are no values?

2

Have you configured any persistence for this ihem?

Try

logInfo("Meterstanden", MeterElekDag.lastUpdate.toString)
logInfo("Meterstanden", MeterElekDag.previousState.toString)
3

this looks better! The lastupdate output is correct, but the previousState not.

2017-11-03 16:33:46.746 [INFO ] [.smarthome.model.script.Meterstanden] - 2017-11-03T09:58:31.560+01:00
2017-11-03 16:33:46.753 [INFO ] [.smarthome.model.script.Meterstanden] - org.openhab.core.persistence.internal.QueryablePersistenceServiceDelegate$1@12556fe

I changed it to

logInfo(“Meterstanden”, MeterElekDag.previousState.state.toString)

Now I get the correct entry

Thanks!