Plasma floating head...

[Davek0974]

Brilliant,

so where do I find this macro method ?

sounds much better

or I could alter the post to issue a g92.1 at the end of each run?

[JAZZCNC]

Brilliant,

so where do I find this macro method ?

sounds much better

or I could alter the post to issue a g92.1 at the end of each run?

Just try searching the Mach3 forum and look at the Wiki for it's Commands etc.

Yes you could just have it insert g92.1 and maybe thats how it's done in plasma but me personally I would use the more conventional Macro approach.
To be honest I'm sure I've seen some thing around for Sheet Cam that use's modified M3 spindle Macro to do this very thing you want.? If I was doing it that's how I'd approach it and just have sheet cam insert M3 in the G-code.

[Davek0974]

Ok I'll go search again, sheetcam already inserts M3/M5 as they control the torch on/off for plasma.


dave

[JAZZCNC]

Ok I'll go search again, sheetcam already inserts M3/M5 as they control the torch on/off for plasma.


dave

Ok well just insert the G31 and all the Dro Zeroing code and any other things you want it to do before the On/Off in the M3 macro.

To be honest after thinking about it just using the G31 G92 way is a little risky because it doesn't do any Error checking on the probe.
By that I mean lets say if your material has curved and is touching the torch or bit of dross just happens to short or cut the wire so it's gone to ground the machine won't know about. The G31 will work just the same has far the g-code is concerned, but in affect it did nothing other than register the point the machine was at already. The G92 offset and retract etc will be applied from this wrong point.!!

So to stay correct you should really have some error checking Code testing if the probe Input is at ground before using G31 which using a Macro you can do.

Your probably thinking not a big deal but I use probe plate all the time and it happens more often than you probably realise and while it not life threatening it's a pain in the arse when you have accidentally grounded the plate. Which by the way your material will act has My plate so if it touchs any part of machine that my ground it same will occur.
So if I didn't have Error checking warning me before starting same would happen and crashes and all sorts of unwanted head scratching stuff would occur.!

[Davek0974]

I see, but in my case, I have a micro switch connected to the floating head, I know it would not be good to start if the torch is already down but my torch parks at the top so may not be an issue.

i can't find a decent, understandable macro anywhere.

[Davek0974]

I've had it running today, have been manual feeding it these commands...
G31 Z-100 F300 this lowered the head from wherever it was sitting and stopped when the probe switch closed.
G92 Z0 Set offset to zero.
G00 Z20 This moved the head back up by the amount of float head travel I have.
G92 Z0 Set offset to zero.
G00 Z1 This raised the head a further millimetre.

It it all seemed to work ok, I would use a macro with error checking but really can't find any understandable code.

it would be useful if someone could post some macro code that could be inserted into the M3 command, all I want to do is probe the surface before every cut starts.

[Davek0974]

What would this code do if place into the M3 command in mach...

DoOEMButton (1010) 'reset z DRO
Code "G4 P1" 'wait
Code "G31 Z-100 F250" 'probe surface
While isMoving()
Wend
ZprobePos = GetVar(2002) 'get contact point
Code "G0 Z" &ZprobePos 'return to point to remove overshoot
While IsMoving()
Wend
DoOEMButton (1010) 'reset z DRO
Code "G4 P1" 'wait
Code "G0 Z20" 'remove floating head travel
DoOEMButton (1010) 'reset the z DRO
Code "G4 P1" 'wait
.....continue on with normal M3 stuff


Would that not probe the surface and leave my Z DRO at zero ready for the M3 command to complete?


This is all theory but I do write VB programs in my day job and it seems very similar

[Davek0974]

Ignoring the probing code for a while, is there any reason that the probe switch distance should not be as short as possible, maybe 5mm?

I have mine built at 20mm but having sat and watched it today, it looks like 5mm would save a lot of Z axis travel time.

Is there any reason for a bigger gap or is smaller always better?

[JAZZCNC]

Ignoring the probing code for a while, is there any reason that the probe switch distance should not be as short as possible, maybe 5mm?

I have mine built at 20mm but having sat and watched it today, it looks like 5mm would save a lot of Z axis travel time.

Is there any reason for a bigger gap or is smaller always better?

Sorry Dave I've been busy and had no time to reply regards Code. I'll have a look at what you put earlier and get back to you thou other than checking OEM codes etc it looks about right.

Only reason I can see for higher switch is in case material sprung or fell between grid and angled up slightly then you'd have some clearence for traveling between pierce points.?

[Davek0974]

Thanks, I'll try lowering it tomorrow, can't see any point in wasting time while it just goes up and down :)