Thanx been there too, that post is ref back to where we are now, Machsupport and the two threads they refer to there also don't have much....
But I have studied the PDF that the author of the Modbus pde file for the arduino and Mach typed, and it seems that (perhaps I am getting close to understanding it better) one has to have the register tables and reference sheets printed out and have them next to the laptop/PC when within a brain as it seems that specific kind of in-outputs and functions have specific addresses in Modbus and is seemingly also restricted to specific registers. So perhaps having these next to the PC it might be easier to write a brain that will be functional.
All I need to do now is to write a couple of small test brains and see if I can get some reaction from any of the features on my machine.