Mach3 Plugin

Discuss Laser CNC Software Issues

Mach3 Plugin

Postby bdring » Wed Dec 22, 2010 2:37 am

I had a little glimmer of hope out of the Mach3 plugin today. I am testing the theory that Tweakie runs at a much higher resolution than most of us. I dialed my KL 4020's up to 8,000 steps/in and setup a Mach3 profile to test it. I started out with my normal kernel speed of 60kHz. I turned up the motors, but that kernel speed limited me to around 450 in/min.

I setup a 600x600 image with a 2in x 2in output and a 0.002 inch Y step over. It started to run and was actually putting down some decent power. The image was not very sharp and it stopped with an error about 10% complete. I repeated several times and continued to get that error. I don't recall the exact error text, but it sounded like the computer was not able to keep up with the 60k kernel speed. (It is a decent quad core machine with nothing else running.)

I lowered it to 25kHz. I was now limited to about 180in/min. I started another engrave. I was putting out more than enough power and the image was a little sharper. I am going to continue to play with the setting to see if I can improve it.

The flexibility of the KL 4020s is nice. I can easily switch from 250 to 16,000 steps/in by flipping DIP switches. I am going to run the FSE controller though this setup to make sure there is not something in my setup affecting the sharpness. The FSE is usually pretty foolproof though.
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

Re: Mach3 Plugin

Postby lasersafe1 » Wed Dec 22, 2010 2:54 am

I'm actually surprised that you haven't dug into the code and found the reasons. With your demonstrated programming skills in other projects I thought it would be a no brainer. What surprises me even more is that no one seems to be pursuing EMC2. Clearly Linux has a tighter control over the parallel port than any Windows system. That was immediately apparent to me when I played with both Mach3 in Windows and then EMC2 in Linux on the same PC set up for dual boot. EMC2 won hands down when it came to the smoothness of the motor stepping. It also had a very nice utility for setting up the motors by swinging the motors back and forth while you adjust ramp acceleration and speeds. Just my two cents.
lasersafe1
 
Posts: 599
Joined: Fri Nov 27, 2009 8:23 pm

Re: Mach3 Plugin

Postby bdring » Wed Dec 22, 2010 3:08 am

I have read the code several times. Actually my request on the Mach forum got the source code released. I have spoken about the issues before, but never really had the tools to compensate for the fixed pulse issue. The plugin taps into the basic kernel and you don't know what happens in there. The plugin allowed me to keep 40uS pulse even when the kernel speed was set above 25,000KHz which does not make much sense because 40uS would be longer than any period above 25kHz. Maybe 40uS just means, the full length of the period.

I think my next test will be a lower resolution of 6250.
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

Re: Mach3 Plugin

Postby Tweakie » Wed Dec 22, 2010 2:54 pm

Another Aztec calendar recently done in reverse on some mirror tile using the Mach3 plugin.
(The result is better than the photo, mirror is real hard to photograph).

Tweakie.
Attachments
DSC00612a.jpg
DSC00604a.jpg
Tweakie
 
Posts: 120
Joined: Tue Apr 27, 2010 5:17 pm
Location: UK.

Re: Mach3 Plugin

Postby macona » Thu Dec 23, 2010 6:42 am

bdring wrote:I I started out with my normal kernel speed of 60kHz. I turned up the motors, but that kernel speed limited me to around 450 in/min.
'

I have mach on a bunch of different machine and it is real difficult to get anything useful out of it past 60KHz. I was running 60-65 on my CNC mill but with the new MachStdMill screen set I had to lower that as I was having glitches. Thats a decent speed AMD 64bit processor in there (And the last AMD I will ever buy)

Next machine is my Hercus CNC lathe. It is running a CoreDuo at 2GHz. I also have a hard time getting even up to 45khz. Get glitches there too. Need to go through the system and optimize and see if that helps.

I also have it on my little cnc lathe but that runs a smooth stepper so the point is moot.

Top kernal speed really depends on the motherboard and is the biggest variable. Some boards run great, some not so.
macona
 
Posts: 363
Joined: Tue Aug 17, 2010 10:30 pm

Re: Mach3 Plugin

Postby bdring » Thu Dec 23, 2010 1:30 pm

Often at the higher ranges, I start to hear the problems. Instead of a perfect tone coming out motor you hear a little a little "Wow and flutter". I'll bet the younger, digital crowd never heard those terms :D
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

Re: Mach3 Plugin

Postby lasersafe1 » Thu Dec 23, 2010 2:05 pm

The glitches are due to the non deterministic timing of the various threads handled by Windows. This is why you see all these warnings on the Mach3 forum about turning off other threads that can occasionally want to start up and check something (like anti-virus software). Each time another thread jumps in, it adds a delay that was not expected by your stepper motor and it throws off the momentum and can cause it to slip poles.

I am not a big Linux fan because I never took the time to fully work with it, but at least I know enough about it to know that they are capable of running "real time" operating systems with highly deterministic timing. The retina engrave card and the DSP cards are very nice, but I think that one day we will see someone make a linux build specifically for running a CNC laser that can match their performance. After all, we are comparing a 100Mhz microcontroller against a machine that can deterministically run threads at Ghz. This build will be a variant of EMC2.

It is true that motherboards can also cause some differences, but this is because the software running in the BIOS can also change timings. Even in those instances, you can usually turn off the offending processes in the BIOS.

Off the subject, I took one of my old PC's that I retired and loaded a linux system called AMAHI on it. This created a home server that has been running for about a year now without a single reboot. It stores my music library and makes network drives that are available to all other pc's in my house. They also have some cool linux builds now to make your own DVR and server for HDTV.
lasersafe1
 
Posts: 599
Joined: Fri Nov 27, 2009 8:23 pm


Return to Software

Who is online

Users browsing this forum: No registered users and 7 guests

cron