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Author Topic: Controlling THC?  (Read 16573 times)

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Offline Davek0974

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Controlling THC?
« on: April 25, 2014, 05:42:44 AM »
For those of us not fortunate enough to have an embedded THC system, i.e. we are using simple boxes like the PromaTHC which only output up, down & arc good signals, is there a way to control THC within Mach3 Plasma?

I have got two macros - M10 & M11 which contain one line - EndTHC() or StartTHC(), I used M10/11 as they seem to run without causing a glitch in axis movements.

In Sheetcam, we have new cutting rules to play with, I have one which turns off (supposed to) THC when it starts a small circle and back on after.

However, when the code is running, you can see the Z motor moving the torch when it is supposed to be stationary while cutting the circles.

The THC Led on the Mach screen stays on continuously regardless of the M10/11 issued, not sure if that is right or if it is indicating that the macros are indeed ineffective?

Is there a working method of doing this or have I missed a step out?
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline stirling

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Re: Controlling THC?
« Reply #1 on: April 25, 2014, 06:18:11 AM »
M10 & M11 are in-built reserved macros - you can't re-program them. They are designed for laser users and turn on and off designated outputs upon axis movement. It doesn't matter what you put in the TEXT files M10.m1s or M11.m1s - it won't be run.

User macros start at 100

Offline Davek0974

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Re: Controlling THC?
« Reply #2 on: April 25, 2014, 06:21:15 AM »
Ah, bugger  ;)

I tried higher number macros but they created a serious glitch in the movements, however, with the new rules system I have more control so will have another go at them.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Controlling THC?
« Reply #3 on: April 25, 2014, 06:43:42 AM »
Moved to M101/102 and it seems to be ok now, the LED goes on/off as well :)

With the new Sheetcam rules, the pauses in movement do not seem to occur as we now have more control over when the M code is inserted.

thanks for the help
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline stirling

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Re: Controlling THC?
« Reply #4 on: April 25, 2014, 06:47:12 AM »
The "rules" are called the post processor or just the post.  ;)

Macro pauses shouldn't be an issue for what you're doing as you're doing it BETWEEN cuts not DURING cuts.

Offline Davek0974

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Re: Controlling THC?
« Reply #5 on: April 25, 2014, 06:58:49 AM »
AFIK, the new rules are not connected with the POST, they are a feature built into the actual main body of Sheetcam, the THC codes in the POST need to be disabled to make them work correctly :)
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline stirling

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Re: Controlling THC?
« Reply #6 on: April 25, 2014, 07:17:49 AM »
Sorry but that makes no sense to me - the pause for an M code is down to how Mach executes them. SCam has no control over that. Wherever you put an M code - it will always cause a slight pause. Whether that pause is an issue depends on where it is. If it's DURING CV'd feed movement then it will affect movement - If it's BETWEEN rapid and feed movement, or between exact stop feed movements the pause won't matter. You could always put M codes in any of these mentioned positions. I'm still using SCam 4.0.19 and I can turn THC on/off whenever I like with no pauses during cutting. YMMV.

Offline Davek0974

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Re: Controlling THC?
« Reply #7 on: April 25, 2014, 07:52:04 AM »
Hmm, I'm on V6.01, maybe a change?

Anyway, it seems to be working so all OK.

Dave
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline Davek0974

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Re: Controlling THC?
« Reply #8 on: April 25, 2014, 09:08:27 AM »
. I'm still using SCam 4.0.19 and I can turn THC on/off whenever I like with no pauses during cutting. YMMV.

Would you care to divulge how you do that?

Anyway, as I'm still learning here, as an experiment, i tried the job below, picture attached.

N0010 (Filename: Test 1.tap)
N0020 (Post processor: Mach3 THC with scriber 2.scpost)
N0030 (Date: 25/04/2014)
N0040 G21 (Units: Metric)
N0050 F1
N0060 G53 G90 G40 G64
N0070 (Part: Test 1)
N0080 (Operation: Outside Offset, 0, T2: 1.5mm Steel, 30A, Std Tip, 103v)
N0090 G00 X41.3478 Y30.1053
N0100 G28.1 Z3.00 F800.0
N0110 G92 Z0.0
N0120 G00 Z3.9000
N0130 G92 Z0.0
N0140 G00 Z3.5000
N0150 M03
N0160 G01 Z1.0000
N0170 M101 (THC Off) (On arcs)
N0180 G03 X50.9478 Y20.5053 I9.6000 J0.0000 F2310.0
N0190 M102 (THC On) (On arcs)
N0200 G01 X72.6444 F3300.0
N0210 M101 (THC Off) (On arcs)
N0220 G02 Y9.4947 I14.3556 J-5.5053 F2310.0
N0230 M102 (THC On) (On arcs)
N0240 G01 X29.3556 F3300.0
N0250 M101 (THC Off) (On arcs)
N0260 G02 X0.5522 Y9.7414 I-14.3556 J5.5053 F2310.0
N0270 M102 (THC On) (On arcs)
N0280 M101 (THC Off) (On arcs)
N0290 X9.7414 Y29.4478 I14.4478 J5.2586
N0300 M102 (THC On) (On arcs)
N0310 M101 (THC Off) (On arcs)
N0320 X29.3556 Y20.5053 I5.2586 J-14.4478
N0330 M102 (THC On) (On arcs)
N0340 G01 X50.9478 F3300.0
N0350 X52.4478
N0360 M05
N0370 G00 Z10.0000
N0380 X0.0000 Y0.0000
N0390 M05 M30

It's a dog-bone shape, so I presumed that THC would be off for the curves and on for the straights, this sort of made sense. However, as expected there is a pause at the end of the lead-in (unexpected but i can understand why) then one at each start/end of arc. The odd bit is the two extra pauses on the left hand arc, these made no sense and it seem sheetcam has thrown a wobbly at this point so i will pop it over on their forum too.

So, due to my lack of knowledge, is this shape possible with THC on/off or should it just be kept off and fingers crossed???
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives

Offline stirling

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Re: Controlling THC?
« Reply #9 on: April 25, 2014, 11:12:42 AM »
. I'm still using SCam 4.0.19 and I can turn THC on/off whenever I like with no pauses during cutting. YMMV.

Would you care to divulge how you do that?

Maybe slide the finger off that trigger Dave - don't want to shoot yourself in the foot. Right?

Re-read my last post - it's all right there.

It's a dog-bone shape, so I presumed that THC would be off for the curves and on for the straights, this sort of made sense.

Why? You've mentioned this before about turning THC off for arcs - why? Generally speaking unless you're doing small holes - just leave THC ON.

The odd bit is the two extra pauses on the left hand arc, these made no sense and it seem sheetcam has thrown a wobbly at this point so i will pop it over on their forum too.

Look at the code - lines 250 to 320 - it's made of 3 arcs. Between each, you turn THC ON and then immediately OFF again.