Servo Wiring and Tuning detailed How To example Mesa 7i77.

Hi I`m relatively new to Linuxcnc but not new to cnc machines.
 I am retrofitting a bench top cnc mill made by the Light Machine Corperation and I am in the process of testing the motors and drives,
the motors are Lifton 24V brushed servo motors with 1000 line quadrature encoders and the drives are Copley Controls 412`s.
My setup is a Mesa 6i25 and a 7i77 controller, I currently have two of the motors and drives setup as a lathe configuration in Pncconf.
The drives are adjusted so that when power is applied the motors are stationary in thier deadband without input, but the moment I connect
the inputs and enable the dirves the motors run away and cause a following error and also you can`t control them using the open loop test 
in Pncconf.
As for tuning I`m possibly doing somthing wrong or there is a hardware problem, my attempt at tuning with the calibration page and 
hal scope I have  set all the perameters to zero and 1000 with any number inbetween and I can`t change anythig all the motors do is run away and cause
a following error whatever setting I try !
Could someone please help and give me an idear of what to try next.
www.actronic-solutions.de/files/actronic/FTPROOT/400ce.pdf    

these are your drives ?  here is how I would approach this, disconnect the motor and put a load resistor across the drive output say 20 ohm , 40 watt, grab one of amazon, something in that neighborhood for size. Enable the drive, measure the voltages across "leave tach connected" Tach, Motor out, speed input, and then if you could I'd like to know the voltage difference between the ground plane of the Servo drive and the 7i77. 

There is something a bit funny with the attached HAL fie, but I think that is probably an artefact of how it was attached.
For example the line has the d missing from the end. And the x PID gain setup has line-wraps between the [TAG] and VALUE.

However if that was the case in the real HAL file I don't think it would load.

I didn't see anythng obviously very wrong. So the next thing to do is have a look at the pid command, feedback and output using halshow (show hal configuration in the Axis GUI, I am not sure how to launch it in other GUIs but in all cases "halcmd loadusr halshow" at a command prompt will launch it. You need the "watch" tab to see live values.

Hi I have tryed the experiment wit the 100 ohm resistor and I got the following results, with no input voltage and the drive not enabled the x axis had 1.8v across the resistor, and withe the drive enabled the  resistor had 61v across it  wit  0.8v on the input. The z axis had 0.5v not enabled and 61v enabled with 0.225 votts on the input.
You can adjust the volts on the motors by turning the gain pots down, this stops them running away but i can`t seem to get linux to give me a reasonable input volage either by running the program or jogging. I think it might be the 7i77 but  not sure ??
 

P.S What signals do I need to look at in the HAL configuration ?

I would disable feedback (you can do this on a per joint basis by setting P, I, and D to 0)
and then set the output voltage by setting the PID bias parameter. (you can set this live with
the calibrate menus "Test" button)

This should allow you to:

1. Check the 7I77 output voltages (7I77 unconnected to drive)
2. Check the drive behaviour when set voltage are applied from the 7I77 (7I77 connected)

The maximum  voltage I can get out of the 7i77 is 0.096v (disconected) and 0.078 connected, it doesn`t matter what value is in the bias field there is no change in output voltage from the 7i77 when you press the test button.
Assuming linuxcnc is ok then to me its pointing to the 7i77. what do you think ??