M1G Common Negative Quick Question

[RichardU]

In this picture, A is the negative coming out of my Auxilliary power supply. B is the 485 Data bus. And C is the AC "negative" going into the M1G. 
 
Am I supposed to connect A to B? If not, to what exactly should I connect A so that I have a common negative? 
 
What about C?
 
Thanks, Richard
 

 

[RAL]

You should connect the DC negative terminals on A and B together to provide a common reference for any devices that are powered by the aux supply that also connect to the M1.
 
Do NOT connect that common negative to C.   That's an AC voltage that will cause damage if you do connect it to the DC power.