THC not activating

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09 Nov 2022 04:03 #256259 by Jalapeno56
Replied by Jalapeno56 on topic THC not activating
Maybe I spoke too soon.... Update does not work for my build apparently, I am stuck on 223.185. one of the many errors: W: Possible missing firmware /lib/firmware/i915/cnl_dmc_ver1_07.bin for module i
915

I definitely don't remember such tight tolerances for velocity to get the thc to work and its sparingly at best. Something changed, Maybe me, maybe the program. I was able to make this work in 30 minutes last time and I was clueless then. Im not a Phd by any means , but this time I have spent almost 16 hours and $200 worth of metal to get back to where I was 8 months ago. I have spent hours reading. Everything I find is vague at best. What is the best way to set Velocity and Acceleration for each axis? And "what sounds good" is not acceptable, I am a newbie and have no clue what is good or bad.  Not trying to be rude, I just dont know.
Here is my current ini file...
Please and thank you
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09 Nov 2022 05:51 #256263 by rodw
Replied by rodw on topic THC not activating
What OS did you upgrade to?
What does uname -v say?

The i915 is an intel graphics driver which they stuffed up in kernel 5.19 which Debian bookworm used briefly (now on 6.0). I don't think it was going to get fixed until kernel 6.1 which I think may be in the Bookworm repo so it could be installed from synaptic.

As far as velocity and accelleration goes, there is no benchmark as it all depends on your gantry weight, motor voltage, motor specs, gearing and other factors. The acceleration target should be 0.3 G (3000 mm/sec/sec,  118 in/sec/sec). You really need to do a lot of trial and error with real cuts as if you tune for maximum linear motion, the wheels will fall off in the real world. I learnt this from some brutal crashes.... :)
 
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11 Nov 2022 00:16 - 11 Nov 2022 00:19 #256394 by Jalapeno56
Replied by Jalapeno56 on topic THC not activating
uname -v: #1 SMP PREEMPT_RT Debian 5.10.84-1 (2021-12-08)
My install is a probably a one-off. I am fairly sure I did everything the hard way. I am running Debian 11 with Linuxcnc 2.9. You and several others helped me many months ago get all the right things in the right places to make this work.

Maybe I just don't have my head wrapped around the terminology.
My assumption is that MAX_VELOCITY would be the fastest feed rate possible.
MAX_ACCELERATION would be how fast it gets to max velocity.
However, when leaving MAX_VELOCITY alone and turning MAX_accel up to 100 IPS2 in the ini file, the movements are super fast with a 200IPM setting in material tab. Change the material tab feed rate to 50 and the speed is exactly the same according to Halscope. Is my gcode lacking? And why is there a button to disable the Velocity Anti Dive if it doesn't disable it? Disabled anti dive would be super helpful in troubleshooting. I feel as though I have gone from one extreme to another with velocity and accel settings with no real indications of where to go. I don't remember having these type issues in the beginning other than learning how PIDs work. Definitely not saying that I know what Im doing, just that something, somewhere has changed and I cannot seem to find it. On a positive note, the last OS update did fix my issue of the wifi turning on and off randomly!
Last edit: 11 Nov 2022 00:19 by Jalapeno56.

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11 Nov 2022 05:26 #256405 by rodw
Replied by rodw on topic THC not activating
If you have lots of short segments and corners, physics means you will never get to max velocity regardless of  your cut speed.
I don't think the MDI uses max velocity and speeds either.
 
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11 Nov 2022 11:08 #256413 by tommylight
Replied by tommylight on topic THC not activating
-check the machine velocity and cutting feed rate
-cutting feed rate can not be higher than max machine velocity
--
From what i gathered, that is the only issue.
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12 Nov 2022 19:36 #256523 by Jalapeno56
Replied by Jalapeno56 on topic THC not activating
It is most definitely fixed this time! I checked the velocity by cutting 2 inch lines with x-vel-cmd in halscope running. The velocities were spot on with commanded vs. actual.
The acceleration however was way off. I adjusted the MAX_ACCEL in the ini file match commanded vs. actual and I am actually cutting better than before! I also ran arc voltage that helped me see that 1 out of 5 pierces, the THC delay was a bit too early causing erroneous sampling. I am assuming that the acceleration problems were due to gantry weight, friction, driver and stepper limitations, etc., something Rodw mentioned. And thank you Tommy for the idea of checking! I know verification should be the first step in troubleshooting, but I seem to run around with blinders on sometimes!
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12 Nov 2022 19:47 #256525 by tommylight
Replied by tommylight on topic THC not activating
A bit of testing always helps a lot! :)
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