Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: sinkyster on April 24, 2012, 03:11:57 PM

Title: Pause Mach3 with miss fire?
Post by: sinkyster on April 24, 2012, 03:11:57 PM
Hi,

would it be possible to pause mach3 when the plasma had a misfire? We sometimes cut a lot of holes and afterwards we would see there is a few holes missed because of misfire issues...

Any Ideas? Or is there already something like that in place?

Thanx!

CD
Title: Re: Pause Mach3 with miss fire?
Post by: Hood on April 24, 2012, 03:36:41 PM
If there is a signal out of the plasma when a misfire occurrs then it would be simple enough. Dont know anything about Plasmas so not sure if that is a standard thing or not?
Hood
Title: Re: Pause Mach3 with miss fire?
Post by: sinkyster on April 24, 2012, 03:40:11 PM
Maybe I can use the Arc Good signal. Whenever a "Good Arc" is established in the machine (current flowing) it close a contact inside for signal purpose. How do I hook up that signal to pause Mach3?
CD
Title: Re: Pause Mach3 with miss fire?
Post by: Hood on April 24, 2012, 03:49:07 PM
Is ArcGood not a normal signal to Mach? If you had it in on Input 1 to Mach then enabled the option on General Config G Code would not proceed unless the signal was seen. Not sure if that would work properly though as it may just stop all code.
You could use a brain to look at it instead and have other factors such as whether Mach is moving to call a feedhold if its not seen when its meant to.
Terry would be the guy to say as he uses Plasma a lot, I am sure when he sees this thread he will pop in.
Hood
Title: Re: Pause Mach3 with miss fire?
Post by: sinkyster on April 24, 2012, 03:52:01 PM
Thnx, will wait for him!

 :D
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on April 24, 2012, 09:06:11 PM
What type syytem are you using(;-) Candcnc? other?

(;-) TP
Title: Re: Pause Mach3 with miss fire?
Post by: sinkyster on April 25, 2012, 04:53:52 AM
We use a local (other) system.

CD
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on April 25, 2012, 10:37:40 AM
DO you run a THC? What type

IF you are running a THC then you have the things you need to do a Feedhold  on MISFIRE.

IF you do not run a THC then you will have to run a signal (ArcGood) from the plasma unit to Mach3.

THen in your M3 macro you need to add a couple lines of code do check for arcgood before it releases the Macro and MACH3 does any motion.

We can help with the macro code.

(;-) TP
Title: Re: Pause Mach3 with miss fire?
Post by: sinkyster on April 25, 2012, 02:14:38 PM
That sounds like it might work!  :)

We use a Hypertherm Plasma Cutter, so we can use the Arc Good Signal. As for the THC , THAT is local! We use TurboNest for nesting/CAM and we have modified it to disable THC with holes with certain diameter... That is where the problem comes in. When we have THC ON (like you said...) it does work, and machine will not move with THC ON because it is not "authorised" to do so. That part does work! However, whenever we cut the smaller holes with THC disabled the torch sometimes misfire and continue moving, and if the operator doesn't see it, Mach keeps on going because it thinks everything is OK.

So now I want to force MACH to stop/pause when we get no current transfer (good arc).

Any help with the M3 code will help, thanks!! I'm not very good with that...

CD
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on April 25, 2012, 09:20:11 PM
OK what does LOCAL mean for the THC???

What is the input number for the arc good signal?

(;-)TP
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on April 25, 2012, 09:46:00 PM
oops, (;-) TP
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on April 25, 2012, 09:46:49 PM

OK this should work BUT it depends on IF there is a plugin trying to override it. That is WHY i asked about what THC you were using. IF yours is a simple M3 macro then add the info after the DoSpinCW() statement.

DoSpinCW()
While Ismoving()
Wend
If Isactive(1)=true Then End
If Isactive(1)=false Then
DoSpinStop()
While Ismoving()
Wend
DoButton(1)
While Ismoving()
Wend
Message" Feedhold due to Misfire, Press stop then correct misfire"
End  If
End

(;-) TP
   

Title: Re: Pause Mach3 with miss fire?
Post by: sinkyster on April 26, 2012, 06:34:08 AM
Thnx Terry, works!!...BUT...

There is 2 things:
1. It works when the THC is of, it pause and gives the message. I've tested it on my notebook, so it should stop, since I don't have the "arc Good" signal to work with. But now it continues when the THC IS active - EVEN though there is no signal.. ?? Should the macro set a certain variable back to zero again after you have pressed stop or something?
2. The message stays on the screen, can I get rid of it when pressing START again? How?

Thnx so far!

CD
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on April 26, 2012, 02:40:42 PM
That is becasue there is a piece of code somewhere telling it to . It is overriding the M3 code.  WHAT thc are you using. That can answer a lot of questions.

What is in your M3 macro code wise?

(;-) TP
Title: Re: Pause Mach3 with miss fire?
Post by: rrc1962 on April 29, 2012, 10:22:31 AM
Why do you disable the THC on small holes?  We burn holes as small as 1/8" with the THC enabled with no problem.
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on April 29, 2012, 11:33:41 AM
With air plasma some machines struggle cut wise with small radius cuts such as cirlces. EVEN the advise for Hypretherm is to SLOWDOWN the feedrate to improve cut quality of the small holes or arcs.

With most THC you cannot reprogram the Arc voltage on the fly so when you slow the feedrate down it effects the cutting as the cut parmaters are no longer correct. The easy fix is to turn OFF the THC when you slow down to stop the head from diving into the material.

AND there are problems even with that approach with MACH3 as when you command a macro to turn OFF the thc there is a small dwell involved and it creates a divot in the material from the axis being stalled from the dwell while the torch is still ON.

I had talked to Brian about it but have not heard back from him about a solution. I had hoped we could get a new Gcode to turn the THC on/of internally wilthout the DWELL from an outside macro.

(;-) TP
Title: Re: Pause Mach3 with miss fire?
Post by: rrc1962 on April 29, 2012, 12:47:22 PM
In cases like that, we either turn on anti-dive or in most cases just put the THC in manual mode. In manual mode, you contol the Z with a remote pendant. Mach THC is still active so no arc will pause motion. The difference is that in manual mode, once the torch pierces and moves to cit height, you control the Z. Works great for fine detail where the feedrate slows way down.

Anti-dive works also, but I prefer the added control with manual mode.
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on April 29, 2012, 02:22:41 PM
Anitdive does not work in this case as it it based on progammed feedrate verses actual.  IN this case teh Feedrate is correct to commanded so the antidive does not kick in. That leaves it cutting with the WRONG arc voltage for the lower feedrate and the head will compensate by going lower.

MOst do not have a manual override for the THC. ADN in most cases it is not needed for simple corrections to feedrate based on arc angle and span.

It is NOT to correct fine detailed artwork but just to correct things like small holes and an ocassional small tight arc.

On my machine I just layers the areas to be adjusted by tool# and I have MACH3 so that it CAN modify the ARC voltage based on Tool# so it takes care of itself. Most do not have those options and just need a simple fix.

(;-) TP
Title: Re: Pause Mach3 with miss fire?
Post by: rrc1962 on April 29, 2012, 08:07:52 PM
Our THC just compares set voltage to tip voltage and if tip voltage exceeds set voltage + 10%, it goes into anti-dive mode and suspends Z motion.  This all happens inside the THC and has nothing to do with Mach or feedrate.  If the speed slows, the lerf gets wider and the tip voltage increases.  If it increases to 10% greater that set voltage, anti-dive goes active and prevents the torch from crashing.  If the tip voltage comes back within range inside of 5 seconds anti-dive turns off and Z motion resumes.  If not, it shuts the torch down.  Aside from the fact that your speed slows without reducing cutting current, which may not produce the best cut, the system does do a good job of preventing a torch crash.

I'm guessing that by saying that his THC is "local" that means he  built it himself.  If that's the case, he should be able to make a few mods to the THC and get it working properly.  The problem is really a THC issue, not a Mach3 issue.   IMO, you shouldn't be turning off THC mode in Mach at all.   If you pierce with THC mode off, you stand a good chance of beginning motion before you have a good arc transfer.
Title: Re: Pause Mach3 with miss fire?
Post by: stirling on May 01, 2012, 05:23:04 AM
Terry - the macro you posted above suffers from some subtle timing issues which is why it's not achieving the desired result. Can I suggest some changes?

First wait a tad for the arc to light - you're not giving the poor bugger a chance.
Then replace your TWO "if"s with an "if then else". Things could change between the two tests - then what?
Now the:

DoSpinStop()
While Ismoving()
Wend
DoButton(1)

If THC is ON then turning the torch OFF will result in continued execution of the gcode. i.e. THC will only wait for arcok IF the torch is ON. HOWEVER the feedhold will be executed before the XY movement has had a chance to start. A feedhold issued when there's no motion is ignored. Hence the behaviour the OP is seeing.

The following mod to your code works here. i.e. it will stop execution if no arcok for both THC ON and OFF

Code: [Select]
activateSignal(OUTPUT1) 'start torch

i = 0
While (Not isActive(26)) And (i < 100) 'wait NO MORE than ~second for arcok - season to taste
  sleep 10
  i = i + 1
Wend

If Not isActive(26) Then 'if no arcok
  doOEMButton(1003) 'we're not moving so a feedhold won't work and stop is better anyway
  deActivateSignal(OUTPUT1) 'turn off the torch AFTER stopping otherwise if THC is on - gcode will resume
  message "Stopped due to misfire" 'issue the message
End  If   

Ian
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on May 01, 2012, 09:23:39 AM
HIYA IAN, Does that cause a one sec delay in motion??  IF you wait up to 1 sec before motion after the arc starts you may have created a big divot in thin guage metal.
We have the SAME type problem with the slowdown routine for arcs and circle. There is a small delay in motion while the macro runs and makes the cut UGLY.

With Guage metal thinner than 14 we run with NO intentional pause after the arc fires.

THe reason for the 2 step approach with if is IF it sees the signal first test it exits without running the rest of the code. Least time delay. BUT I can see where it may MISS the signal on some systems by asking too soon.

Plasma CAN be a tricky critter.

ALSO some of the THC's plugin WILL "override" anything you try to do. The plugin I run automatically will HALT the system on arc loss or no arc on start.

Thanks (;-)TP

BUT I LIKE the code

DUH, I see where it will start as soon as it sees the signal(;-). The plasma side has lots problems with pauses and delays. I still see MACH3 ignore m3s from time to time AND has delays of motion after the m3 starts. COuld be MACH could be plugins?????  COuld be multiMUXed hardware ????

(;-) TP
Title: Re: Pause Mach3 with miss fire?
Post by: stirling on May 01, 2012, 10:17:14 AM
HIYA IAN, Does that cause a one sec delay in motion??  IF you wait up to 1 sec before motion after the arc starts you may have created a big divot in thin guage metal.
We have the SAME type problem with the slowdown routine for arcs and circle. There is a small delay in motion while the macro runs and makes the cut UGLY.

With Guage metal thinner than 14 we run with NO intentional pause after the arc fires.

No it waits UP TO 1 sec FOR the arc to start but continues IMMEDIATELY the arc starts - no delay. (I just read your edit - I think you've got this now)

THe reason for the 2 step approach with if is IF it sees the signal first test it exits without running the rest of the code. Least time delay. BUT I can see where it may MISS the signal on some systems by asking too soon.
Nope - your wrong here Terry. An else is not only the correct way to do it but it's FASTER - you waste time doing the test again when it's not needed. Note my code doesn't even need the else. (EDIT: Mind neither does yours if you used "if NOT isActive" - never explicitly test for equality to true or false - it's not cool  ;))

Plasma CAN be a tricky critter.
I can think of another word than critter - bastard springs to mind!!!

ALSO some of the THC's plugin WILL "override" anything you try to do. The plugin I run automatically will HALT the system on arc loss or no arc on start.
That can NOT be the case here. Any such plugin would just be doing what this is doing so it would just DOUBLE stop things. Remember the OP's problem was that it WASN'T stopping. Unlesshe has a plugin that deliberately continues execution when the arc fails (why?) then this can't happen.

Thanks (;-)TP
Title: Re: Pause Mach3 with miss fire?
Post by: BR549 on May 01, 2012, 11:07:38 AM
HIYA Ian,

Lets see add that tip into the Mach3 CB notebook

GoodTip #7342

SO when are you going to write a book for us lost souls that cannot program???  I hear the title "Programming Mach3 CB for Dummies" is available.

It would probably be less work for you(;-)

THe plasma process is fairly simple to remember it is getting MACH3 to read the plasma torchs MIND  is the problem. The best cutting is done on a foggy night AFTER 11pm in months that contain the letter "R" while standing on 1 leg and 1 eye closed.

Thanks, (;-) TP
Title: Re: Pause Mach3 with miss fire?
Post by: stirling on May 01, 2012, 11:52:26 AM
I hear the title "Programming Mach3 CB for Dummies" is available.
How about "Zen and the art of camel humping"?  ;D

Ian