back up from plc

hello.

suppose that i have a s7-300 plc with cpu315 which has a mc card and battery.there is an op17 that values of op transferred to retentive db on cpu.

will all data on mc be erased if the battery became disconnected?

what does happen on value of db and op if i download the earlier backup file to the plc?

i have a cpu with part number 315-2af01-0ab0.are data blocks in this cpu retentive?

best regards.

hello.

suppose that i have a s7-300 plc with cpu315 which has a mc card and battery.there is an op17 that values of op transferred to retentive db on cpu.

will all data on mc be erased if the battery became disconnected?

Not if the power (24V) is on.


what does happen on value of db and op if i download the earlier backup file to the plc?

You will get the old values from the backup.
If you have the gear to download, why not do an upload imediately?

i have a cpu with part number 315-2af01-0ab0.are data blocks in this cpu retentive?

The DB's values survive a restart of the CPU. Still it might be done a programmed (p)reset in the startup OBs.

Kalle

thanks a lot for your reply.

please excuse me because my english isn't good. are you mean that value of dbs will not be erased after power down of cpu?

are db values saved in mc card?

if i turn off cpu(remove 24v) and pull out the battery the data saved
in mc card will be erased or not?

MC card does not need power to keep its data.