DB initialize

Hello friends, i have a question about the initialize of DBs, what the conditions for a datablock return the initial value? Can happen this whe tunr off/on my CPU? Or only when donwload the block? 

Thanks

lrkunierski

Hello friends, i have a question about the initialize of DBs, what the conditions for a datablock return the initial value? Can happen this whe tunr off/on my CPU? Or only when donwload the block? 

Thanks

The datablock returns to start values when the PLC starts up when the datablock is not set to retain its values. There is also the situation where the retained values are lost -- because of battery failure or power removed from the PLC for too long. The memory clear mode (switch) can also be a cause of a loss in memory _{{statement needs verification}}.

The hardware configuration of the classic PLCs (S7-300 / S7-400) is where the DBs are selected to be retained though a power outage / PLC reset.