PlasmaC Fiber laser 1Kw head height control + auto focuas
btw the encoder signal is very stable,,, i just rewire it again., and start over,, i have very stable readings nowI guess that depends on height measurement scaling
(what distance range scales to 0 --> 10V) and what precision
you need
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- tommylight
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Good.
The slowest thing in your setup is the RS485 interface, everything else is much faster.
i change the head no more rs485
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wetransfer.com/downloads/f1ca513c6e1a26b...0200413172114/ffb78e
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this is my pwm generator,, using stm32 board good for testing
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The core clock speed on 3.3v promini style boards is 8 MHz, providing:
8 MHz / 64 = 125 kHz /13 ticks = 9600 /sec (256 reads =27.6ms, 1024 =106ms, 4096 =426ms) (default)
8 MHz / 32 = 250 kHz /13 = 19230 /sec (256 reads = 13ms, 1024=53ms, 4096=200ms)
8 MHz / 16 = 500 kHz /13 = 38000 /sec (256 reads = 6.7ms, 1024=27ms, 4096=108ms)
8 MHz / 8 = 1 MHz /13 = 76900 /sec (256 reads = 3.3ms, 1024=13ms, 4096=53ms)
based on THCAD it makes how many read/second? 1MHZ
1024=1ms?
this result for promini@8mhz.. i will use stm32@72mhz
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there is no much noise from the system,, 10 bit is good for me
but how can the low pass filtering effect the resolution
Because the THCAD is a V-F converter. It has an output frequency range of
about 100 KHz to about 1 MHz. LinuxCNC reads this frequency by measuring
counts per servo thread period, so if the servo thread period is 1 ms , full scale
volts will read about 1000 counts per servo period (roughly 10 bits of resolution)
If you chose a longer servo period you would have more counts and higher resolution
A low pass filter has a similar effect, that is, the more the frequency output is averaged,
the higher the resolution.
I would try the 9V battery, you should not see 1% of full scale noise, only about 0.12%
(at 1 ms servo thread)
i dont think its calculated this way
because the servo thread check 1000 times a seconds and if i run @ 50khz then 5 pulse will be count in each cycle, this count measure the pulse frequency with 5 pulse per cycle servo threat then count this 5 pulses and measure the frequency
i think adding IIR filter will smooth out those pulses
iir filter will produce more stable and less fluctuated
easyupload.io/540elt
u can see the effect of low freq on the video
also after test i found esp32 a way more better for this application,,, i use the web-server in the esp to set the higher and lower frequency,, and i will add the scale factor there,,
it accept capacitance and analog voltage 0-3.3 for plasma THC becouse probing using capacitance will be faster the float or ohmic, specially for type of sheet we cut
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i dont think its calculated this way
because the servo thread check 1000 times a seconds and if i run @ 50khz then 5 pulse will be count in each cycle, this count measure the pulse frequency with 5 pulse per cycle servo threat then count this 5 pulses and measure the frequency
Actually it _is_ calculated this way when using the Encoder velocity.
Even if the maximum frequency is 1 KHz you still get ~ 10 bit
resolution full scale, this is because of the way velocity is calculated
(its not just counts/servo period)
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for example i have 1k servo and 50khz pwm,,
each count 5 pulse,, but is the 1st pulse is 45khz and second pulse is 46khz pulse and 3rd is 47khz and so on till 50k
( this simulate sheet is moving away from the head)
then Linuxcnc will count the average or those pulses?
more pulse = more accurate signal,.
if the signal is not filtered,, then u have to have more freq,, to build more stable signal
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edge and last edge per period so say you have 4500 hz = 4.5 pulses per servo thread
The encoder component will count 4 pulses and divide 4 by the time between
count 1 and count 4 to get the frequency (4.5 KHz) so the resolution is not
dependent on the number of pulses per servo thread.
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