Light Machine Corp. Benchman XTr (retrofit)

Hi guys,

I also decided to do the 5i25 with 7i77 card for my Benchman XT. This forum's been excellent, I'm very close. I just hooked up the encoder, it increments on the screen when I rotate the motor, so I'm guessing its hooked up correctly. I hooked up the servo, it moves when I jog from the program with the encoder UNPLUGGED (runaway). BUT, when I plug the encoder back in and go to jog, the servo is buzzing and just jittering back and forth. Any idea what the problem is? This is what my config looks like:

#********************
# Axis X
#********************
[AXIS_0]
TYPE = LINEAR
HOME = 0.0
FERROR = 0.1
MIN_FERROR = 0.05
MAX_VELOCITY = 2.0
MAX_ACCELERATION = 2.0
P = 40.0
I = 2.0
D = 70.0
FF0 = 0.0
FF1 = 1.0
FF2 = 0.0
BIAS = 0.0
DEADBAND = 0.002
MAX_OUTPUT = 0.0
ENCODER_SCALE = -50000.0
OUTPUT_SCALE = 10.0
OUTPUT_MIN_LIMIT = -10.0
OUTPUT_MAX_LIMIT = 10.0
MIN_LIMIT = -0.001
MAX_LIMIT = 8.0
HOME_OFFSET = 0.0


My units are inches and I couldnt find any FF values so they are default, the encoder is negative, when I put it positive, it stops at "joint 0 following error". Any feedback is appreciated!

I got the x,y,z tuned now am onto the spindle for this Becnhman XT. Does anyone know how the spindle was controlled by the original nextmove card? Did the computer do the PID controls or did the DDM-019 do the PID controls with a +/-10 voltage from the computer? I think it's the ladder but not sure then why the spindle encoder wires come out of the DDM-019 into the main control board. Just for feedback? The DDM-019 also seems to send a 0-10V output for feedback so not sure why it would need both...

The spindle PID loop is controlled entirely inside the DDM-019 based on the +/- 10V from the computer.
The encoder signals were brought back into the nextmove system for rigid-tapping type operations where we would slave the Z-axis to the spindle rotation.
The DDM-019 analog feedback lines were used to monitor the spindle speed and the spindle load.

Thanks for clarifying that! Much appreciated. I got it to move with a 1.5V battery after I set the motor enable. Any idea why, with no command voltage, it makes a high pitch noise and spins at very low rpm? Do i need to tweak the PID in the controller or is there an easier method (since I don't have a serial port XP laptop)? Should the spindle enable be on when the cnc turns on or just when turing on the spindle?

Even a few millivolts on the command line will make the spindle spin very slowly.
Do not enable the spindle until you are ready to run it.

Ok makes sense, thanks. Do you know what the clocking/anti-rotate pins in the spindle and tool changer carousel are for? I'm onto programming the toolchanger and it would make the program much easier if I didn't have to home the spindle rotation, I'm thinking of removing those pins.

Side note, If you're ever in Toronto area in Canada, let me know, I'd love to buy you a beer, I would not be as far as I am without your input!