Servo Drive EMC Issues...

Well now this is a very odd state of affairs, been start-up testing a machine the last few days with a large amount off servo drives; approximatly sixteen axis each individually AC controlled...Its a monster of a machine but found some huge issues, firstly the person who is getting a serious **** kicking monday morning did not fit earth wires from the RFI filter to any of the drives - and to top that off he linked all the -0VDC wires powering the resolver backup together and then not to the power supply itself! I ended up finding out it was back-feeding through another circuit with a couple of pushbutton lamps on it! :0

However does anyone think this could have directy attributed to all the servo drives having communicaion issues on RS-422, i have had to replace all the RX/TX line driver chips on the PCB's just to get things up and running without random communication errors.

Also the amount of noise generated due to **** poor earthing was phenominal, i had an opto-pushbutton that stopped working once the drives were enabled - even it if i isolated it from the machine and powered it up from a bench top PSU!

Also does anyone have any advice for reducing inrush current on large servo applications? I already have a main incomming 110A RFI filter and each drive has its own filter too... but the surge current is still quite large as AC is supplied from a couple of duel contactors controled from a complex safety circuit.