7i96 Configuration Tool

andypugh wrote:

Y

Basically:
spindle-speed-command => PID command
spindle-speed-feedback => PID feedback
PID-output => PWM value

Be aware of units. Use a revs-per-second spindle speed command, as encoder velocity is in revs-per-second.

andypugh wrote:

Yes, this is a perfect application for a PID controller.

There is an example here: wiki.linuxcnc.org/cgi-bin/wiki.pl?Closed...pindle_Speed_Control

But it isn't a very good one.... It adds the PID output on to the spindle speed command. I presume this is because it is old and dates to a time before the PID component included feed-forward terms.

Basically:
spindle-speed-command => PID command
spindle-speed-feedback => PID feedback
PID-output => PWM value

(ie, the PID is inserted between the spindle command out and the PID command in)

Start with P, I, D all zero and adjust FF0 to give the right speed under no-load. Then adjust I (mainly) and some P to get good stiff speed control.

Be aware of units. Use a revs-per-second spindle speed command, as encoder velocity is in revs-per-second.

# Spindle
setp hm2_7i96.0.pwmgen.00.output-type 1
setp hm2_7i96.0.pwmgen.00.scale [SPINDLE]MAX_RPM
setp hm2_7i96.0.pwmgen.pwm_frequency [SPINDLE]PWM_FREQUENCY

net spindle_on spindle.0.on hm2_7i96.0.pwmgen.00.enable hm2_7i96.0.ssr.00.out-05
net spindle_speed spindle.0.speed-out => pid.3.command
net spindle-speed-feedback hm2_7i96.0.encoder.00.velocity-rpm pid.3.feedback
net pid-output-command pid.3.output spindle.0.speed-out


setp pid.3.Pgain [SPINDLE]P
setp pid.3.Igain [SPINDLE]I
setp pid.3.Dgain [SPINDLE]D
setp pid.3.bias [SPINDLE]BIAS
setp pid.3.FF0 [SPINDLE]FF0
setp pid.3.FF1 [SPINDLE]FF1
setp pid.3.FF2 [SPINDLE]FF2
setp pid.3.deadband [SPINDLE]DEADBAND
setp pid.3.maxoutput [SPINDLE]MAX_RPM
setp pid.3.maxerror [SPINDLE]MAX_ERROR

PCW wrote:

By changing

hm2_7i96.0.gpio.XXX.in

to

hm2_7i96.0.gpio.XXX.in_not

PCW wrote:

If you are in doubt about pin or parameter names you can run

halcmd show all > all.txt

(with linuxcnc running) to get a list of all parameters, pins and signals

There are many ways to reverse a step motor direction
hm2_7i95.0.stepgen.00.direction.invert_output
1. swap one motor winding
2. reverse the direction pin wiring (use DIR- instead of DIR+ for example)
3. invert the direction pin in hal ( setp hm2_7i96.0.stepgen.XX.direction.invert_output true )
4. invert the stepgen scale