John, you are absolutely correct.
Sorry for not updating the thread, we have been slowly chipping away at some of the issues. We wired the machine up as suggested, with the AMPENx in series with the opto-22, so MO will kill the motors etc. We also set up the off on error. We have purchased an oscilloscope, and have found a few interesting things;
- We have traced the cause of the machine running away back to the F to V converters. When you start the machine for the first time (and the motors are stationary), they are outputting a signal of 10v. If the drives are then turned on, the motors run away.
- Switching the drive power off and on will return the output voltage to 0v when the motor is stopped, and the machine is completely controllable until you switch both the cabinet and the computer off.
- Alternatively, the F to V converters have some sort of shoddy switchable circut, which introduces 5v to various places on the board when activated (see photo linked below, the yellow and black wires going into the front of the boards). This is connected to a relay on the opto-22 board, and flicking this on and off a couple of times will set the voltage to 0v when the motor is stationary. You can then turn the drives on and again the machine is completely controllable until you switch both the cabinet and the computer off.
Photo (sorry for the poor quality and large size)
http://img199.imageshack.us/img199/4765/gw06.jpg - Once the machine is controllable, the voltage out of the f to v converters seems to be pretty stable and consistant with relation to motor speed.
- The encoders seem to be only recieving around 4v. They are using the standard galil 5v output, however there appear to be alot of things attached, and the 5v is being pulled down to around 4v. The F to V converters have their own individual precision 5v output, we are unsure if using this would be better or if it does not matter?
It appears that once we have this sorted out, the axies should be functional. Thank you everyone for your help so far.