Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Davek0974 on April 03, 2014, 10:49:21 AM
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In preparation for fitting a THC unit, I thought I'd try adding the M101/M102 THC on/off codes to my sheetcam post.
I have a test job, a 50mm square that has 5mm loops on the corners to keep nice sharp corners, however with the THC M codes added, when I dry-run this code in Mach3 Plasma it runs to a corner, stops, cuts the loop, stops, cuts the next edge then repeats on all corners??
Is there a reason it does this or is Mach not set correctly, surely just adding THC on/off codes should not upset the smoothness of the code?
Without the codes it runs smoothly????
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Try using G64 at the beginning of your code.
G64 = constant velocity
G61 = exact stop
Jeff
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what is in the m101/102 macros?
Hood
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Try using G64 at the beginning of your code.
G64 = constant velocity
G61 = exact stop
Jeff
Neither of those codes appear in my G-code, I will add the G64
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what is in the m101/102 macros?
Hood
Good point, I presumed they were standard Mach macros?
I will have a look
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Macros over 100 are user macros so they are not standard.
Hood
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Ah, My bad. :)
Is there a "Proper way" to do THC on/off???
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Just checked and there are no M101/102 macros in the macros folder, would that explain the behaviour ??
How is this feature enabled??
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Just tried creating a couple of macros, 101 & 102, inside i just placed DoOEMButton(222) Or (223)
It makes no difference, the movement still pauses for probably 10-20ms then starts again at each direction change.
The G-code looks identical, just has M101/2 sprinkled about in it.
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Having ANY m call will delay things, Mach needs to process the info and can not possibly continue at a CV due to that.
Depending on what you are actually doing with the THC signal ( I dont know much abot plasma) you may be able to use m11/m10, with tem there should be no delay.
Hood
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Neither have I ;D
I just assumed that when fit the unit, having the G-Code created by sheetcam tell Mach3 when and when not to use the THC inputs would be a good idea?
I guess I was wrong ???
Maybe it does not matter?
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If they are actual signals going out from Mach to a stand alone THC then likely M11/M10 will do what you want. You have M11 at the start of a line of the code and that sends the signal out as soon as the code starts to execute, M10 at the start will stop the signal, there is no delay as it was designed for laser firing.
Hood
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This is a simple THC, it has three outputs - Arc OK, Torch Up & Torch Down.
I can only use up & down as I only have two spare inputs left on my board.
There is no feed from Mach to the THC, I presumed that having the THC-Off code embedded would tell Mach to ignore any torch up-down signals until it hit an THC-On signal. I am only guessing though.
The unit has an inbuilt adjustable delay that only allows outputs after a certain time from establishing a "Good" arc, I guess I just rely on this.
Does Mach ignore THC up/down signals when doing small circles etc?
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Anyone?
Does Mach ignore THC up/down signals when doing small circles and corners etc?
This seems to be needed to stop torch diving.
I can't find much out about this.
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Might want to PM either Ian or TP as they seem to be the two that know the most about Machplasma.
Ian = http://www.machsupport.com/forum/index.php?action=profile;u=1754
tp = http://www.machsupport.com/forum/index.php?action=profile;u=24665
Hood
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Ok done, many thanks
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For future ref, the feature I was looking for is called "anti dive", just need to figure out what level % of federate to set it for.
Thanks guys.
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Have I got this right?
If I set "Stop CV on Angles" to 90deg, then set set THC anti-dive limit to 90%, if I then put triangle loops on the corners of external squares it will slow down, turn on anti-dive, make the triangle loop, accelerate and turn off anti-dive????
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If they are actual signals going out from Mach to a stand alone THC then likely M11/M10 will do what you want. You have M11 at the start of a line of the code and that sends the signal out as soon as the code starts to execute, M10 at the start will stop the signal, there is no delay as it was designed for laser firing.
Hood
If these two macros were adjusted to press OEMButtons would that introduce a delay again??
I don't need external outputs just a way to switch Anti-dive on and off from g-code without introducing a delay which would cause issues when plasma cutting.
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No idea, as I said Terry and Ian are the guys that can most likely answer your questions regarding Plasma.
Hood
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No idea, as I said Terry and Ian are the guys that can most likely answer your questions regarding Plasma.
Hood
Thanks Hood, I am trying but little or no response, if this were shareware I could live with it but I bought the license ;)
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No idea, as I said Terry and Ian are the guys that can most likely answer your questions regarding Plasma.
Hood
Thanks Hood, I am trying but little or no response, if this were shareware I could live with it but I bought the license ;)
???
I don't need external outputs just a way to switch Anti-dive on and off from g-code without introducing a delay which would cause issues when plasma cutting.
You appear to have the wrong end of the stick regards anti-dive. You turn it on at the beginning and leave it to do it's thing. IT turns THC on and off automatically as required by the %feed setting.
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No idea, as I said Terry and Ian are the guys that can most likely answer your questions regarding Plasma.
Hood
Thanks Hood, I am trying but little or no response, if this were shareware I could live with it but I bought the license ;)
???
I don't need external outputs just a way to switch Anti-dive on and off from g-code without introducing a delay which would cause issues when plasma cutting.
You appear to have the wrong end of the stick regards anti-dive. You turn it on at the beginning and leave it to do it's thing. IT turns THC on and off automatically as required by the %feed setting.
Ah, thanks, that is indeed different to what I presumed.
So what happens when sheetcam sets a reduced speed for say a circle, mach will not see a deceleration as the speed change was programmed, will the torch dive or not?
I can't fathom how it will work with a "dumb" THC like I am in the middle of fitting? It only has up and down outputs (can't use arc ok as I have no more inputs). By embedding on off codes in my g-code I could see how it might work but without that I can't.
Using edited m10/11 macro codes does not introduce a delay so that is one good thing, but if anti-dive is just on, what is left to control torch dive when anti-can't work because it's a coded speed reduction?
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First WHY do you think you need to slow down in a corner ?? Plasma wants a consistant cutting speed. Mach3 is going to slow down on its own as it cannot make corners wide open most times based on the accel/deaccel parameters of the drives. SO when it down slow down on its own the anti dive will kick in and take care of diving due to slower speeds.
IF you let Sheetcam slow the corner speeds THEN you have ZERO anti dive controls on a simple plasma. AS soon as the feedrate drops the arc voltage will go UP and the THC will send the4 torch DOWN to correct the voltage change.
The setup in Sheetcam is for units that control the preset arc voltage parameters on the fly so WHEN you change the feedrates you also change the arc voltage preset as well and then the cuttting stays consistantly good.
CandCNC has a good setup for doing this on the fly. A simple Mach3 plasma cannot. The only solution is to JUST turn off the THC if you make a programmed speed change that is going to effect cutting quality then turn it back on when you return to the proper cutting speeds.
Here I do not require constant tweeking the speeds for corners or circles.
Just a thought, (;-) TP
(;-) TP
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Thanks for that, this is all new to me so forgive me for asking about things that may never happen :)
I presume in a torch dive, it cannot dive below the minimum level set in Mach i.e. 0mm or material surface?
Is there an OEMButton code set for THC on & off, i couldn't see one in the list.
Thanks again
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I also thought it customary to program a speed reduction on small circles to say 60% ?
Surely here I would need to program in a THC off command and on again at the end as Mach has no auto-slowdown for small circles feature.
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If you DO get torch dive it should ONLY be at the start as it gets up to commanded feed and at the end as it slows to a stop. With good accel you shouldn't even get it then.
There is a caveat to this in that you can get dive on a kerf crossing - Mach's anti-dive won't help you there as it's purely speed dependent.
OEM 123 toggles THC on/off. Curiously labelled "Torch Enable Toggle" in the spreadsheet.
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If you DO get torch dive it should ONLY be at the start as it gets up to commanded feed and at the end as it slows to a stop. With good accel you shouldn't even get it then.
There is a caveat to this in that you can get dive on a kerf crossing - Mach's anti-dive won't help you there as it's purely speed dependent.
OEM 123 toggles THC on/off. Curiously labelled "Torch Enable Toggle" in the spreadsheet.
Thanks for that, making more sense now.
The start should be ok as the unit has a built in delay before its starts sending signals.
I did notice the toggle OEM but was looking for an on/off pair, it will work though.
Was i right that it can't dive below THCMin though??
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Z can not be driven lower than THC min by THC - i.e. No. However I have to wonder why you ask. Tell me a value for THC minZ that will achieve something useful.
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:)
What i meant was that if THC Min is zero, and the torch is running say 1.2mm, a torch dive would/could NOT send the torch below THC min, i.e it can only dive as low as zero in this case.
As you said, it cannot so that answers my question and makes sense.
Thanks
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Yes but the point I was trying to make is so what?
So it can only go as low as zero. So what if your metal is warped down slightly at (minus) -0.5mm at any particular point and your THC is cutting just fine? You just trashed the point of having THC because you stopped it following down to -0.5.
Alternatively what if your metal is at +0.5mm at any given point because it's warped up and you DO get a dive for some reason? you just crashed BEFORE you got to Zmin so it saved you nothing.
Which is why I asked you for a value you could put in Zmin that would do something useful ;)
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:)
Having just got the thing running, I now see what happens or at least can happen. I am deliberately cutting with the metal tilted so I can see what goes on, if it started at a high point and couldn't go lower then yes - fail.
I now have -3 min and 5 max, but i think more would be ok although a warpage of 5 to -3 is a pretty bent plate :)
Trying to get it dialled in now, getting top dross at present but at least its running and not crashing the torch or winding it way up high (any more :) )
I think I can see what it needs now.
What sort of values of hysteresis do others use, I'm not sure of the relationship between a volt or two and distance in the arc.
Currently set for +/- 4v
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I now have -3 min and 5 max, but i think more would be ok although a warpage of 5 to -3 is a pretty bent plate :)
Not sure how else to say it really...
What sort of values of hysteresis do others use, I'm not sure of the relationship between a volt or two and distance in the arc.
Currently set for +/- 4v
Rule of thumb? I think it was Hypertherm who told me that in conventional plasma a volt is roughly 0.1mm - never checked it though - it kept melting my ruler.
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Lol :D
One good thing I do have going is a dual-purpose z height probe, first position is probe height, 3mm more is a limit switch so if it did ram the torch, the most that could happen is an e-stop :)
I have a lot to learn methinks, at least it's all playing nicely together now, the hypertherm was a revelation and solved a massive amount of grief with HF issues.
The hard part is learning blind, it would be so much easier to just have someone there to say "do this" or "do that" etc, that is why I have so many odd questions ;)
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the hypertherm was a revelation and solved a massive amount of grief with HF issues.
You have a Hypertherm? So I've spent my time helping you with a competitors THC. Serves me right for not checking I guess. Personally I blame Hood ;)
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I started out with a HF pilot arc setup but it was wreaking havoc with the electronics that I could not surpass so in the end I blew the budget on a Hypertherm powermax 30xp, it's a hand system but all I (only just) afford and with my intermittent proposed usage, seems to fit the task well.
I have just fitted a Proma THC as it really was all I could afford.
Hopefully that's not an issue?
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the hypertherm was a revelation and solved a massive amount of grief with HF issues.
Serves me right for not checking I guess. Personally I blame Hood ;)
Not my fault you are a bit slow on telling people of your product ;D
Why not do as Jeff Birt does and have a link to your product every time you post. I cant see that being a problem as your product (as far as I know) is complementary to Mach rather than competition :)
Hood
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So what IS this product then??
:)
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So what IS this product then??
:)
http://www.razordance.co.uk/THC.htm
Hood
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So what IS this product then??
:)
http://www.razordance.co.uk/THC.htm
Hood
Ah, now I see, won't work for me though as my Powermax 30xp is a hand system and does not have the interface connector, the Proma uses the full arc voltage as reference.
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Not my fault you are a bit slow on telling people of your product ;D
Why not do as Jeff Birt does and have a link to your product every time you post. I cant see that being a problem as your product (as far as I know) is complementary to Mach rather than competition :)
Just silly old me sticking to the forum rules in "Promote and discuss your product" I guess.
Ah, now I see, won't work for me though as my Powermax 30xp is a hand system and does not have the interface connector, the Proma uses the full arc voltage as reference.
Fair enough if it's just for personal use. Mine is designed purely for machine torches as Hypertherm don't sanction the use of hand torches for mechanized cutting. (An H&S minefield which I keep well away from).
Out of interest though - what do Hypertherm say about your warranty now you've opened the box and added a non-Hypertherm accessory?
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Well, unless they employ an internet detective to link the machine back to me, they wont know:)
The manual gives directions as to how to open the case for cleaning etc, it's then just two wires to two terminal points and put her back together again.
the torch was easily and invisibly modified to give me a trigger input.
I can take the torch off and be hand cutting with just an allen key and pulling two small plugs :)
And yes, this is totally home usage, I would not let anyone else use a modified system like this as there now two trigger points etc
Personally I think they should add the voltage divider and socket then market this machine for home use cnc. Its a great little unit, yes it does have 35% duty cycle but thats 3-1/2 minutes of non-stop cut, if i get a big job i'll just program an M0 and let it sit for few minutes then press cycle start again.
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if i get a big job i'll just program an M0 and let it sit for few minutes then press cycle start again.
Better still just have a G4P... in your code :)
Hood
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if i get a big job i'll just program an M0 and let it sit for few minutes then press cycle start again.
Better still just have a G4P... in your code :)
Hood
That's a timed delay??
I was not keen on that because it means the machine will restart automatically without warning, I thought having to go press cycle start was a better option.
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Personally I think they should add the voltage divider and socket then market this machine for home use cnc. Its a great little unit
Or even up the power a tad and add the option of a machine torch - they could call it... erm... a PM45.
Seriously Hypertherm do more than enough options already - I've been trying to keep up with their gazillion models each with a gazillion options for years....
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Personally I think they should add the voltage divider and socket then market this machine for home use cnc. Its a great little unit
Or even up the power a tad and add the option of a machine torch - they could call it... erm... a PM45.
Seriously Hypertherm do more than enough options already - I've been trying to keep up with their gazillion models each with a gazillion options for years....
Yes but the PM45 is at least £450 more than the 30XP and for home use the 30XP is already top budget.
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Yes but the PM45 is at least £450 more than the 30XP and for home and the 30XP is already top budget.
Which is why surely, your 30XP doesn't have your suggested additions - or do you want them added for free? ;)
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Yes but the PM45 is at least £450 more than the 30XP and for home and the 30XP is already top budget.
Which is why surely, your 30XP doesn't have your suggested additions - or do you want them added for free? ;)
Ok, Ok I give in :)
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Dave as far as the min max if you set the min too short then if you touch off on a high spot on th emetal then start to cut when you get to the low spot you may run out of range and the cut quailty suffers. Now IF you are worried that the torch may snag on the plate somewhere set your Z lower limit at just below the table surface to phelp protect the torch crashing into the metal below the top of the table and hit the slats.
My best advice is to stop worrying about what ifs and get to cutting, pay attention and take notes. I could spend DAYS talking to you about what you MAY see or not as you may never run into some situations.
Plasma cutting HAS a very steep learning curve to it. It takes time to master ALL the different things that you will need to learn.
You do have a magnetic breakaway torch mount RIGHT ??? If not that would be my next purchase or build one yourself.
As to Stirlings HT connector it is just a connector right ? Buy a mating plug and wire the unit into your Machine as you have done the other thingy.
I was hoping that Stirling would bring his stufF to the USA but as HOOD suggested I think he is hiding it from us (;-) Probably does not want us to pick on him.
Just a thought, (;-) TP
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Dave as far as the min max if you set the min too short then if you touch off on a high spot on th emetal then start to cut when you get to the low spot you may run out of range and the cut quailty suffers. Now IF you are worried that the torch may snag on the plate somewhere set your Z lower limit at just below the table surface to phelp protect the torch crashing into the metal below the top of the table and hit the slats.
My best advice is to stop worrying about what ifs and get to cutting, pay attention and take notes. I could spend DAYS talking to you about what you MAY see or not as you may never run into some situations.
Plasma cutting HAS a very steep learning curve to it. It takes time to master ALL the different things that you will need to learn.
You do have a magnetic breakaway torch mount RIGHT ??? If not that would be my next purchase or build one yourself.
As to Stirlings HT connector it is just a connector right ? Buy a mating plug and wire the unit into your Machine as you have done the other thingy.
I was hoping that Stirling would bring his stufF to the USA but as HOOD suggested I think he is hiding it from us (;-) Probably does not want us to pick on him.
Just a thought, (;-) TP
Thanks for that,
I do tend to focus on the what-if's too much :)
I also tend to have lots of questions when met with things that are either not straight forwards or not explained in any manual etc.
I will be looking into a mag torch mount soon but my floating head has a limit switch as well so if it rams the slats it will just stop, not so good in a runaway where it rams while moving along as well but better than nothing.
I tried setting z-min soft limit but it seems to get upset by my probing using the work offsets and threw up a lot of soft-limit errors so i have just disabled soft-limits on z now.
It's cutting at least :)
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As to Stirlings HT connector it is just a connector right ?
Nope - it's the solution to a whole legal nest of vipers. :o
I was hoping that Stirling would bring his stufF to the USA but as HOOD suggested I think he is hiding it from us (;-) Probably does not want us to pick on him.
Check your PM inbox around August 2011 Terry. That's the one where I offered you one for free in return for testing it out for me. You declined. You had the chance then to pick on me for FREE - now if you want to do it it's going to cost ya. ;D
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HIYA Stirling you are correct I remember the offer since you mentioned it, BUT there was not anything here to run it on at that time .
DID you get the serial interface working to be able to talk to your THC from Mach3 ?? To be able to change the preset voltage on the fly ?? That is what is needed to do feedrate slowdowns for arcs and keep the cut quality correct. Would be a handy item to have for the hobbiest that has a bare bones plasma cutter. An auto version that did Preset arc voltage changes on the fly based on Feedrate would be nice. I did some mods to the CandCNC that did it. You Help me with the programming to interface mach3 back through the CandCNC . I had to jump OUT to a VB script then bring it back into Mach3 and then back to the THC to reset the arc preset value to match a feedrate change.
THat was a WHILE back though.
Here I cut with an older HT1000 (Hypertherm) and it does NOT have the magic plug either.
(;-) TP
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Yes - modbus. SetV can be changed on the fly either by screen control or via gcode. There's an option to use ArcOK via pin or without (freeing up a pin for G31 if you want). You can do the SetV as a function of F in the (SCam) post.
No magic about the plug - as I said - just legal begal stuff (over this side of the Pond anyway - don't know about Floyda).
Cheers Terry
Ian
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It would NICE for the machine to auto compensate the preset Arc Voltage by itself. That way when fine tuning with FRO it would balance itself out.
Sort of a Cruise control for the arc voltage control,
(;-)TP
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sounds cute Terry but I wonder if it's really practically useful.
As you know V and F are not a linear relationship so you'd have to define curve data for it to work on. Sounds like a lot of work for dubious advantage (IMHO) - less of course you can convince me otherwise.
Ian
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OK IF (;-)
"" You can do the SetV as a function of F in the (SCam) post."" AND it works
Why would it not work in Mach3 ? Last I checked the V_F relationship was very close at the same "power" (AMP) setting.
Seems awhile back I did some testing on this with the CandCNC THC. I will see if I can dig up the notes again The CandCNC unit DOES have a cut parameter TABLE that holds all the cut parameters.
I seem to remember that I monitored the F VEL and adjusted the SetV based on F vel. about the same routine I did with a router to adjust the F vel based on the spindle RPM. As the spindle RPM slowed it slowed down the F vel to compensate.
More thoughts came to mind:: When I loaded the Cut file Mach3 checked the ratio of the Preset Voltage to feed speed and THAT set the ratio for that cut file. THen as I FRO up and down it auto changed the preset volts to compensate . That allowed the cut HEIGHT to remain constant with the FRO changes.
3 important things for cut quality
Constant Vel on feedrate
Constant Cut height (THC control)
Proper power level for material AND torch components
Just a thought, (;-) TP
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I'll give it some thinks and get back - gotta go.