Hank,
Setting up the parameters from scratch isn't too terrible, but it sounds like you are going to have to have someone write a new PLC program too.
Maybe you'll get lucky and the PLC will still be there.
To enable the PLC onboard, you need to go into the machine parameters:
Press the DIAGN key.
Press the PLC I/F softkey.
Type this in:
(1001)( )(M)
Press "Input"
Then go to the Parameter screen. The machine parameters should be enabled.
BTW, to switch back to user parameters, enter (1001)( )(U) on the PLC I/F screen instead.
Press the "MENU" softkey and then the "BIT-SEL" softkey.
You need to set bit select parameter 51 to "00000001"
After setting, you should be able to press the "F0" key. When the onboard is enabled, you will see a message and some softkeys.
Hope this helps,
Scott