Hello I have a similar problem but my machine was working properly and there was no battery error. One fine day it was working fine and the next morning I get the 3 PLC Stop Error. Moved the indicator to 2, then started getting the Operator Keyboard Error. I tried efen connecting the padovani keyboard to the X142 but that wont work  but was still worth a try. 

I need to restore my TEA1 & TEA2 and i so have PG-2000 and STEP5 but dont know or have the correct cables. 

Any solution apart from buying the Operator Keyboard? 

Thanks and Regards 

machine: Padovani Labor E350 

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Split from Help sinumerik 805 retrofit in a metal lathe PADOVANI.