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  • spumco
  • spumco
31 Jan 2025 21:30
Replied by spumco on topic PROBE RADIUS COMPENSATION

PROBE RADIUS COMPENSATION

Category: General LinuxCNC Questions

  • my Questions are : 
    • 1- if i switched to spherical shape instead of rectangular one will it simplify the calibration process, especially when compensating for B-axis tilt?
      2- is there is a predefined probe radius compensation in linuxcnc which i can use and it take considaration a titled workpiece
      3- For a DIY probe using the method described above (24V signal on contact), will this provide sufficient accuracy and reliability for calibration purposes or should I invest in a commercial probe for the long term ?

  • 1 - All commercial calibration artifacts I've seen are spheres
    • They are attached to the work surface, and the probing routines (DIY or purchased) probe the sphere at various locations - including A- and B-axis tilts.
    • Center of rotation for each rotary axis is calculated after the calibration ball is probed in multiple locations
    • Some machines then write the absolute value of the rotary axes CoR to non-volatile parameters for use by TCP.  All that's needed from that point is to re-probe a few locations after operation to check & adjust for thermal changes.
  • 2 - A number of the GUI's available with LCNC have probing features/functions.  I believe all of them have some sort of probe tip diameter compensation adjustment.
    • I don't think any of the LCNC GUI's offer rotary axis calibration probing macros, however.
  • 3 - This is not the way commercial probes work - they don't pass current through the probe and part back to the controller.
    • Probes have a number of internal mechanism designs, but they are essentially a switch.  When the probe stylus is touched/displaced from it's resting point, the switch triggers and the controller sees that state change as a 'touch.'
    • Higher-cost probes use internal strain gauges to detect stylus deflection.  Lower-cost probes use the 6-ball mechanism Andy mentioned in his response.  An internet search for 'CNC touch probe mechanism' or similar should help you visualize what's going on inside.
  • If you don't want to DIY a probe, and you don't want to pay for a Blum or Renishaw, there are lower-cost probes (wired & wireless) available which provide quite decent results.
    • The nice thing about purchasing a higher-end probe is that they generally come with a suite of probing macros which can be installed on the controller.  I've never used a commercial probe with LCNC, so I don't know if commercial probing macros are compatible.
  • 10K
  • 10K's Avatar
31 Jan 2025 21:20
Replied by 10K on topic Spindle Pulses Lost in System

Spindle Pulses Lost in System

Category: General LinuxCNC Questions

The counts are all negative, that is they get more negative when the spindle is turning. Same for the RPM. I have an entry in my postgui that flips it:
setp scale.0.gain 60
setp lowpass.0.gain 0.010000
net spindle-velocity-feedback-rps               => lowpass.0.in
net spindle-fb-filtered-rps      lowpass.0.out  => abs.0.in
net spindle-fb-filtered-abs-rps  abs.0.out      => scale.0.in
net spindle-fb-filtered-abs-rpm  scale.0.out    => gmoccapy.spindle_feedback_bar
  • PCW
  • PCW's Avatar
31 Jan 2025 21:09
Replied by PCW on topic Spindle Pulses Lost in System

Spindle Pulses Lost in System

Category: General LinuxCNC Questions

Check that the counts are going up (the count direction depends on the state of the 'B' encoder input)
  • tommylight
  • tommylight's Avatar
31 Jan 2025 21:06
Replied by tommylight on topic Brilliant Bambu Lab

Brilliant Bambu Lab

Category: Off Topic and Test Posts

More choices
  • Cant do this anymore bye all
  • Cant do this anymore bye all's Avatar
31 Jan 2025 20:55
Replied by Cant do this anymore bye all on topic The dumification of humanity through internet

The dumification of humanity through internet

Category: Off Topic and Test Posts

The Lunch box thing makes sense the creator is from Germany. As shown in the above post.
  • 10K
  • 10K's Avatar
31 Jan 2025 20:54
Replied by 10K on topic Spindle Pulses Lost in System

Spindle Pulses Lost in System

Category: General LinuxCNC Questions

I moved wires around on my BOB so that the encoders are connected to the proper inputs on the Mesa 7i92.. I made some changes to the .HAL file. I got several things working:

1) The spindle speed shows up on my display, and matches what I see on my separate DRO, even at 2,000 RPM.

2) Based on Tommylight's earlier question, I figured out why my HalScope was running at 250Hz (double click on samples button, and changed divisor from 4 to 1. That change made the missed pulses go away completely, and validated my cheap Chinese BOB was not glitching.This is the first time I've ever seen 180 pulses per revolution on the HalScope.

 

3) I used a stopwatch to time 10 seconds, and watched hm2_7i92.0.encoder.00.count. I had calculated I should get 1440 pulses in 10 seconds at 48 rpm, and that's almost exactly what the difference was in the pulse counts before and after. That means that all the pulses are all being seen! I figured out later that I also could just rotate the chuck by hand, and see 180 counts per revolution.

The only remaining problem I have is that something is mis-configured in my .HAL. When I try to thread, the cutter moves in to position, and is either not receiving the index pulse to start or the 180 pulses per revolution or both, and is not starting to thread.
loadrt [KINS]KINEMATICS
#autoconverted  trivkins
loadrt [EMCMOT]EMCMOT servo_period_nsec=[EMCMOT]SERVO_PERIOD num_joints=[KINS]JOINTS
loadrt pid names=pid.x,pid.z,pid.s
loadrt hostmot2
loadrt [HOSTMOT2]DRIVER config=[HOSTMOT2]CONFIG
#setp   hm2_7i92.0.watchdog.timeout_ns 25000000
setp   hm2_7i92.0.watchdog.timeout_ns 10000000
#loadrt encoder num_chan=1
loadrt abs count=1
#0-invert is used in pendant hal file
loadrt scale names=scale.0,0-invert
loadrt lowpass count=1

addf hm2_7i92.0.read              servo-thread
addf motion-command-handler       servo-thread
addf motion-controller            servo-thread
#addf encoder.update-counters     servo-thread
addf pid.x.do-pid-calcs           servo-thread
addf pid.z.do-pid-calcs           servo-thread
addf pid.s.do-pid-calcs           servo-thread
addf hm2_7i92.0.write             servo-thread
#addf encoder.capture-position     servo-thread
addf abs.0             servo-thread
addf scale.0             servo-thread
addf lowpass.0             servo-thread

# latch all stepgen position counts 50 usec before nominal read time (add per PCW):
setp hm2_7i92.0.dpll.01.timer-us -50
setp hm2_7i92.0.stepgen.timer-number 1

# increase tolerance to read errors
# setp hm2_7i92.0.packet-read-timeout 30 --removed per pcw 12/25/24
setp hm2_7i92.0.packet-error-limit 100

# ---setup spindle---

# set the HAL encoder to 180 pulses per revolution.
setp hm2_7i92.0.encoder.00.scale 180

# set the encoder to non-quadrature simple counting using A only.
setp hm2_7i92.0.encoder.00.counter-mode true

# connect the HAL encoder outputs to LinuxCNC
net spindle-position hm2_7i92.0.encoder.00.position => spindle.0.revs
net spindle-at-speed => spindle.0.at-speed
net spindle-velocity-feedback-rps hm2_7i92.0.encoder.00.velocity => spindle.0.speed-in
net spindle-index-enable hm2_7i92.0.encoder.00.index-enable <=> spindle.0.index-enable
net spindle-phase-a hm2_7i92.0.encoder.00.input-a
#net spindle-phase-b hm2_7i92.0.encoder.00.input-b
net spindle-index hm2_7i92.0.encoder.00.input-index

#  ---probe signal---

net probe motion.probe-input <= hm2_7i92.0.gpio.020.in

# --- ESTOP-EXT ---
net estop-ext     <=  hm2_7i92.0.gpio.014.in_not

# --- BOTH-HOME ---
net both-home-x     <=  hm2_7i92.0.gpio.016.in
net both-home-z     <=  hm2_7i92.0.gpio.003.in_not
  • Cant do this anymore bye all
  • Cant do this anymore bye all's Avatar
31 Jan 2025 20:50
Replied by Cant do this anymore bye all on topic The dumification of humanity through internet

The dumification of humanity through internet

Category: Off Topic and Test Posts

Ok once again its a regional thing.

Silicon was given the name Silicon in 1817 Thomas Thomson.

In 1787, Antoine Lavoisier suspected that silica might be an oxide of a fundamental chemical element,[18] but the chemical affinity of silicon for oxygen is high enough that he had no means to reduce the oxide and isolate the element.[19] After an attempt to isolate silicon in 1808, Sir Humphry Davy proposed the name "silicium" for silicon, from the Latin silex, silicis for flint, and adding the "-ium" ending because he believed it to be a metal.[20] Most other languages use transliterated forms of Davy's name, sometimes adapted to local phonology (e.g. German Silizium, Turkish silisyum, Catalan silici, Armenian Սիլիցիում or Silitzioum). A few others use instead a calque of the Latin root (e.g. Russian кремний, from кремень "flint"; Greek πυρίτιο from πυρ "fire"; Finnish pii from piikivi "flint", Czech křemík from křemen "quartz", "flint").
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