Driving a charge pump with a Mesa 5i25 stepgen

flat lined high or low?

Ack! I didn't look carefully at the hal file you posted

It has nothing setting x-enable at all (nor are any of the other stepgen axis enabled)

I would start with a pncconf created hal/ini file set,
there seems to be a lot missing from yours

The HAL file was based on one generated by pncconf (see attached for pnconf one).  I deleted out all the PID-related stuff because my system has no position feedback and the home / limit switch stuff because it doesn't have those either.  I also got rid of the "closed loop stepper signals" section for each joint, which looks like it was probably a mistake to do looking back at it now (I just saw closed loop and thought it didn't apply to my system).  Those sections look like:

# ---closedloop stepper signals---

net x-pos-cmd    <= joint.0.motor-pos-cmd
net x-vel-cmd    <= joint.0.vel-cmd
net x-output     <= [HMOT](CARD0).stepgen.00.velocity-cmd
net x-pos-fb     <= [HMOT](CARD0).stepgen.00.position-fb
net x-pos-fb     => joint.0.motor-pos-fb
net x-enable     <= joint.0.amp-enable-out
net x-enable     => [HMOT](CARD0).stepgen.00.enable

Also got rid of HALUI, coolant, probe, and toolchange sections toward the end.

But, the charge pump section still has the line

net x-enable => [HMOT](CARD0).stepgen.04.enable

So I'm not sure why that's not outputting.

Are you saying the that complete pncconf created file does not drive the chargepump? It should (though at 2500 Hz)

Your original hal file will not because x-enable is unconnected (not driven by any pin so always has the value of 0)

I would start with a pncconf created file and only change the chargepump frequency (it looks like pncconf calculates it wrong)

I went back and edited the pncconf-generated INI file as follows:

-commented out these lines:

#HALFILE = custom.hal
#POSTGUI_HALFILE = postgui_call_list.hal
#SHUTDOWN = shutdown.hal

-changed [KINS] and [TRAJ] coordinates to XYZY (were XYYZ)
-put joint 3 as Y2 and joint 2 as Z
-made step scale value for Y2 negative

And edited the pncconf-generated HAL file as follows :

-changed stepgen.04.position-scale and stepgen.04.velocity-cmd values to fix charge pump frequency
-removed toolchange, coolant, probe, HALUI, and home / limit switch sections (tried commenting out each section one at a time so I could see the effect)

The PID stuff is apparently important - if you comment that out, LinuxCNC will start up fine, the charge pump works, and you can home the axes, but the second you go to jog, it faults.  So that stuff should be left alone in the INI and HAL files.  The "closed loop stepper signals" sections in the HAL file should be left alone too.  Working INI and HAL files attached.

Once I was able to jog and issue MDI commands, there was only one thing left to check - the "spindle".  Grabbed my laser safety googles (and respirator) and was able to turn it on and off via MDI.  I loaded up an old nc file that I had for a wooden bracket and ran that on some scrap cardboard, which came out swimmingly.  See attached pic.

Lesson of the day is don't delete stuff you're not really sure about and if you are going to delete stuff, trying commenting one thing or section out at a time.

Thanks again for your help, Peter!

P.S. Other changes to the INI file that I forgot to list:

-got rid of kinstype=BOTH callout in [KINS] section
-added HOME_SEQUENCE values in each [JOINT_#] section:

joint 0 (X) --> 0
joint 1 (Y1) --> -2
joint 2 (Z) --> 1
joint 3 (Y2) --> -2

Negative for the Ys keeps them from being jogged independently in joint mode.  More info in section 8.3.6.10 of the 2.8.2 documentation .

Thank you for interesting post

I have a question: with the parallel port, can the frequency be generated with a stepgen, for Driving a charge pump?

Yes, you can run a stepgen in velocity mode to generate a square wave at a
selectable frequency.

man stepgen

Thanks for your answer, could you post a general example of how to do it?