Machsupport Forum
Third party software and hardware support forums. => Galil => Topic started by: mikey9911 on June 29, 2009, 10:51:29 PM
-
Has anybody tried to write code for the galil controller to use the analog input for torch height control without going through mach3. It appears that mach has to slow an update rate 10hz or is there away to get mach to look at this faster.
-
It will have to be done on the Galil. I'm not real familiar with the concept of THC, so if you will explain what needs to be done, I'll put it in the plugin.
Things like do you need to configure a max movement range. And what happens at +10v and -10v. +10 is Z riased and -10 is Z0? Stuff like that.
Steve
-
If you look at the experimental thc plugin written by Brian Barker it has everything needed. But it has to be done in the galil for the fast update. It should only work when the torch is in motion.
-
has anyone got this right on the galil yet? if so can you share your code
-
You can help us by giving details of what you want it to do and how you want it to work electrically. I know nothing about plasma cutting, but can make the plugin better with your help. Please e-mail me with some information so that I can get working on it. Thanks,
Kenny
-
http://www.candcnc.com/
see dthc section
basically it requires an analogue input to read from a voltage divider circuit ( 0-400v dc at torch cathode output divided down to give 0-10 v at galil input)
the operator sets initial pierce height (variable for different material/thickness etc) above the metal which is higher than the cut height, also a variable parameter set by the operator for material to be cut.
the plasma should have a floating head with height rference switch touch off on it. ( z reference lowers the torch, in switched off condition to metal . the torch continues down until it activates the the z reference switch fitted to the floating head. at this point the z is raised by the travel of floating head to z ref switch plus pierce height to give correct pierce height above the metal
an output is then given to the torch on relay. starts plasma arc and pierces metal
the plasma outputs an arc ok signal back to control to tell control it is on once arc is established
the control dwells for a parameter set time (to allow full pierce of the material)
the z is now lowered to the parameter set cutting height
motion commands given to start cutting movement
during movement the voltage divided signal is referenced continually and any change moves the torch up or down to keep the arc at the precise voltage.
the voltage / current loop is what makes for a perfect cut.
this movement must be virtually instantaneous to keep the arc set as required.
also this needs to be able to be disabled or reduced at very slow feed rates ie tight corners to stop the torch diving down into the metal in corners where it is cutting faster than its moving
-
by the way i have a candcnc unit here but its not a stand alone unit. it works with their interface and breakout only and outputs step/dir to motors only
i dont like the way their auto install removes any other saved profiles from mach so only their stuff turns up in mach loader!
they use serial com port for speed required to update.
-
Is there any news on this thc in galil as I have begun working on the plasma again and would still like to use thc in the galil
-
Sorry,
No progress to report at this time. I could use some help determining what needs to happen.
Thanks,
Kenny
-
I'm currently fitting a galil/mach combo to a woodworking machine (one router spindle, 10 vertical drills, 6 horizontal drills, grooving saw, 7 position tool changer), and I've just reached the point of controlling the three axes by mach (rapids at 65 (2560 inches)/min!). I really like the fact that with the galil plugin, mach is operating as the front end of a proper industrial control.
I also have a plasma table that runs off an old Burny 2.5 control, which works fine, but I find it limiting because the memory is so small, and it's really slow to download and calculate kerf offsets etc. I also want to add a torch height control, and I am attracted by candcnc's integrated mach solution, but I feel like it'd be a backwards step (no pun intended..) to remove the closed loop control and replace it with a parallel port solution- I'd really like to run it off a galil and retain the current drives and servos, but the integrated THC products don't work with the galil plugin.
The candcnc THC uses the serial port to relay arc volts etc back to mach- wouldn't this be relatively straightforward to do via the galil plugin, using one of the analogue inputs on the galil? I'm speaking from (my usual!) position of almost total ignorance about mach and the galil language, but in principle the THC is just an ADC (with all the noise supression etc around it), isn't it?
If Tom Caudle at candcnc did a galil-plugin version of his THC, surely it would be an extremely attractive retrofit for all the thousands of commercial servo-based plasma tables already out there (particularly since the existing analogue drives could be retained)?
X and Y axes, as well as an integrated servo-driven torch lifter, all controlled by the very fast bombproof galil.... I'd buy one. Please Tom!
-
isteve p. here as well!
i was thinking about this yesterday, wondering if i could add plasma to my "duzzit"
i think it could be done quite easily using the plasma screen set with a few modifications, as just about everything is already there.
the only thing that puts me off doing it to mine is the machine has too high inertia so wouldnt accel/decelerate fast enough for plasma without overshooting position
im going to find some space to put the plasma table back together and do this with an old pc fitted with 1750. il use the voltage divider from toms thc as i have it here.
im sure kenny will help like he has so many times with the galil plugin lately.
im pretty sure the thc could be run easily in a seperate galil thread using the notify plugin passthrough to send the settings from the screen to the thc thread variables
>:D
-
I don't know why I bother posting on these forums, I might as well just pick up the phone and call you!
Somehow I knew you'd be the one to sort it out.. I've got a nice advantech industrial pc with a 1750 inside, which is the perfect size to fit in my burny cabinet, so get that plasma table out and get cracking! You'll have it finished in a week at your usual rate.
The amount of **** that the plasma produces would make a right mess of your biesse, my table is extracted out through the roof, but if I forget to turn the fan on for a few seconds the smoke is everywhere.. Maybe you should set up your machine outside to alleviate your space problem as well as the fume problem?...
-
I have recently installed Mach3 + Galil DMC-1830 on a large plasma cutting machine. I was planning to use the CandCNC torch height controller (LCTHC). I purchased the unit without consulting Tom at CandCNC and learned during the installation that it wouldn't work with the Galil board.The Mach3 + Galil combination is excellent. Would it be possible to run a thread(subroutine) on the Galil dedicated to reading two inputs - the torch up and torch down inputs - to modify the torch position?
Steve Hasbury
-
I'd like to try that, but, if you have a contact at C&CNC, and he would e-mail me at the address in the PDF manual for the Galilplugin, I am willing to try and make it work properly. I don't know anything about their torch height control, but am willing to learn, if they are willing to help me.
Thanks,
Kenny
-
I've emailed Tom Caudle about using his THC products with the Galil plugin, but he feels it's too much of a niche to make it worth putting time into. I thought there could be quite a lot of owners of analogue-drive servo machines out there like myself, who would be interested in a Mach solution.
The candcnc THC (MP3000) is embedded into Mach, and Tom doubts whether the communication between the Galil and Mach would be fast enough, or would have too much latency, for real-time control via Mach.
Ive noticed recently that Tom now markets a low cost THC, which seems to me to perform the main tasks required of a THC (filtering and dividing the arc voltage, comparing it to a reference and outputting torch up/down signals). It doesn't appear to me to be embedded into Mach in the same way as the MP3000. Ive been thinking that surely we can use the LCTHC, but send the torch up/down signals to the galil, which then drives the axis. This would be done without mach's knowledge, so effectively would be a standalone THC, with Mach running the X and Y axes only.
Obviously, if one of the galil analog inputs could be used to monitor the arc volts, compare this to the reference voltage on a second analogue input, and get the data record back to Mach fast enough for Mach to drive the Z axis, it would be great, but if it's not feasible then perhaps the above idea might still allow for a low-cost retrofit solution?