[odingalt]

My previous post is still pending moderation, but I'd like to update that post as I found some useful information in the EMC2 documentation pertaining to my question. (Dear Moderator, please merge my two posts). Here 'tis below:

property name="spindlepwm1" type="float" value="0.2"
property name="spindlepwm2" type="float" value="0.8"
property name="spindlespeed1" type="float" value="100.0"
property name="spindlespeed2" type="float" value="800.0"



PWM Rate
The "carrier frequency" of the PWM signal to the spindle. Enter "0" for PDM mode, which is useful for generating an analog control voltage. Refer to the documentation for your spindle controller for the appropriate value.

Speed 1 and 2, PWM 1 and 2
The generated configuration file uses a simple linear relationship to determine the PWM value for a given RPM value. If the values are not known, they can be determined. For more information see section ([.])

If I am reading this correctly then, for the stepconf posted above, the spindle is assumed to run at 100RPM for a 20% duty cycle and 800RPM for an 80% duty cycle. And the relationship inbetween is assumed to be linear.

The EMC2 documentation goes on to talk about spindle speed calibrating and measuring the spindle speed. Does anyone know what tool could be purchased to measure spindle speed??

[odingalt]

One thing I'm not currently able to locate within the stepconf file is the PWM frequency. Any kind souls with EMC2 willing to open White Quark's stepconf file to reveal the PWM frequency?

http://lab.whitequark.org/files/3020T.stepconf

[odingalt]

Answer to another of my own questions. To measure spindle speed, if you are a hobbyist, build some sort of reed switch / magnetic switch and write custom software for a microchip PIC controller or Arduino or similar.

For a for-profit guy like me, buy a "non-contact Tachometer" from E-bay. You apparently would stick a piece of reflective tape on one of your bits, turn on the spindle, and then hold this device up to the spindle to detect the reflective tape and get a count of RPM's

Digital Laser Photo Tachometer Non Contact RPM Tach Meter Motor Speed Gauge USA | eBay

[vbgraves]

I control my router with a SuperPID. It incorporates an optical sensor to provide speed feedback for control. Calibrating the LinuxCNC pwm was fairly straightforward if you follow their procedure. If I remember correctly, they just default to the 0.2 and 0.8. I don't remember what my values ended up being.

[odingalt]

Please merge post with http://www.cnczone.com/forums/linuxc...conf-file.html

[andypugh]

Answer to another of my own questions. To measure spindle speed, if you are a hobbyist, build some sort of reed switch / magnetic switch and write custom software for a microchip PIC controller or Arduino or similar.

No need for that, LinuxCNC can convert pulse-frequency to RPM using the "encoder" HAL component in counter-mode. Set the scale to 60 and the encoder.N.velocity HAL pin value will be rpm directly.