Siemens S7 EPROM and battery

At the factory where I work we have a baling machine controlled by an S7 PLC. Recently I had to replace it. When I first went in the panel, the PLC had a small module marked "battery" plugged into a slot. A similar type of module marked EPROM was in a bag at the bottom of the panel.

On fitting the new PLC, I fitted the EPROM in the slot to load the program into the PLC. It seems that the program is for a series of machines and once loaded, several parameters must be set for our particular machine. Now every time the machine is powered down, we have to enter these parameters, obviously because the battery is not plugged in to hold the settings.

How do I get the battery in without losing the program. I assume swapping the EPROM for the battery when the power is on, is a bad thing to do. Yet if I swap it with the power down, the program is lost.

I'm more familiar with S5 where the EPROM and battery have seperate locations.

Are we talking S7 200 series here ?

Yes I think it is. I'm at home now and I shouldn't be thinking about work, but 216 rings a bell, It's about the size of a brick, has 24 inputs and 16 outputs. The module/battery fits into a small slot on the left hand side below the run etc LEDs.

In that case when you power down and take the eeprom out then fit the battery the super-capacitor should hold the program in memory with no problems. On powering up with the battery just reset the parameter defaults. If when you power down and take the eeprom out the plc does loose its program then i would guess the super-capacitor isnt holding its charge so replace the plc. (As long as its had enough time to charge - how much time? Dont know couldnt find that info!)

You could leave the plc powered up, flick the switch to stop swop out the eeprom to a battery then flick to run. (I would however have a spare plc on the shelf if this is a production machine! incase the plc does go pop!)

One other thing, I presume the battery is new ?

You could also buy some more eeproms, have these preset set up for each machines as defaults and put an eeprom in each machine with the relevant defaults etc