Neilzebub

The last input on your  FX3GE40M should be X27 therefore the first input on your extension block should be X30, the last output should be Y17 so your first extension block output should be Y20. Note extension blocks always start their addressing with the next available multiple of 10 (30, 40 ,50 etc) if your last input on your PLC was X24 the first input on your extension would be X30. This is all done automatically, and doesn't require any setting up in software.