Hey Kostas;
I received your PM and I'll try to help if possible.
I'm assuming that you have installed the xml file from cnc4pc website. Please check the following.
Make sure to define pin 14 for step in motor outputs!
These manuals are not very clear in that the on board relays operate using pin 1 and 16 which should be defined on the output signal screen output 1 and output 2. In the engine configuration ports and pins screen and define m3 and m4 (cw and ccw) pins as 1 and 16 in the relay control section. What you have done is define mach output 1 for m3 (cw) and output 2 for m4 (CCW) which correspond to predefined pins 1 and 16 and spindle direction control.
When you test your spindle voltage at the BOB, go to the MDI screen and type in M3 for cw operation then a speed value such as s12000. This should give you a voltage output at the analog out terminal of the c11 card. The potentiometer is just for trimming the speed to the most accurate value and will not cause a voltage change if the speed command is not entered.
Also, I've switched all of my equipment to PMDX BOB and smoothsteppers.
Sooooo, please be aware that I'm not near my equipment and working from memory using the information you have provided and a very old memory!
Hope this helps.
Bill
billyjack
Helicopter def. = Bunch of spare parts flying in close formation! USAF 1974 ;>)