Siemens Step 7 Global Data Block

Just a quick question I can't find an answer on yet.

I have created my own recipe structure using a Global DB and when I came in this morning after a powered down weekend, I noticed that all of the values in my recipe DB are blank?

Is the Global DB a volatile memory? Meaning when it powers off the memory is not retained only the structure?

If so how can I make it NON-volatile?

Thanks

Assuming a 300 series PLC here. If that is the case DBs are retained by default. I believe when the CPU powers down it writes all data to the SD card.

I am not sure if this is the case for older 300's that had the batteries.

For the 1500's the DBs are not retained by default. Instead there is a column where you must select each item individually to retain them.

back to the 300's. If you do a 'edit - intialize datablock' it will write all the intial values to the DB (in the configuration software). Then you would download the intialvalues. Or if you perform a memory reset via the switch on the PLC that will write the default values to the DBs.

What's the plc type? Old S7 with battery?