forum.cncdrive.com

There are two basically THC futures:
First - THC on/off future - allow to hold XY machine moves when ArcOK signal from plasma cutter turn off.
Second - turn on/turn off automatic torch height control during cutting (from the THC inputs control - torch freeze - antidive, on corners, etc... ) using internal THC logic or commands from Gcode (M205/206).

When I try to turn on/off automatic height control from Gcode (M205/206) UCCNC enable/disable first basic THC ON/OFF future, not automatic height control and then it is clear what is happening. For example if I need to disable control on the hole (THC OFF by M206) no wait for ArcOK.
Correct me if I'm wrong.
Thank you!

Yes, exactly with an extension:

When THC is on and setting "Control THC even if the THC on signal is not active" is not set and M3 is active then there is wait for ArcOK.
If any of the above is not true then there is no wait for the ArcOK.
So, yes, if you turn the THC off (M206) then there is no wait for the ArcOK.

Hmm, it's not good.
I think this two futures must be separated. Just no sense to control THC ON/OFF global future (wait for ArcOK) from gcode. Operator in any time can enable/disable THC from the screen.
Then M205/206 codes can enable/disable Automatic Height Control during cutting. IMHO it's will be easy and clearer for all.
Of course this is my opinion.... But may be you have other more compelling reasons for current algorithm.

As far as I remember this is done the same in Mach3, those functions are not separated, the THC on off and the M3 together controls the wait for ArcOK.
I beleive we implemented these exactly the same...

What about using M207-M212 given for corners + small circles you're trying to inhibit downward motion?

M205 : Turns THC on in synchronous with the motion.
M206 : Turns THC off in synchronous with the motion.
M207 : Turns the THC delay on in synchronous with the motion.
M208 : Turns the THC delay off in synchronous with the motion.
M209 : Turns the THC anti dive on in synchronous with the motion.
M210 : Turns the THC anti dive off in synchronous with the motion.
M211 : Turns the THC anti down on in synchronous with the motion.
M212 : Turns the THC anti down off in synchronous with the motion.

Yes, Anti dive inhibits downwards THC control automatically if the feedrate drops under the set %, it acts in syncron with the motion buffer.
And Anti down is similar, but manually switchable, so while it is on it will disable the downwards THC while the function is turned on.
The basic idea behind the anti-down is that CAM softwares can be coded to insert the anti-down on/off macros to problematic points of the path, e.g. small circles and cross-sections.
These macros are built in ones and they do not cause any delays, they act in syncron with the motion buffer, they are inserted in the motion buffer just like if they were some motion commands between other motions.
And these macros also have non-syncronous equivalent button codes to call asyncronously from button presses or plugins etc.

Yup, that's how I use them in my sheetcam post processor.... maybe with the neuron THC shad requires one of them linked to an output pin (optional setting... like m10/m11)... hence thc can be enabled via m205, but the neuron can be told via fast acting hardware pin that thc downward motion or any motion (2 hardware pins maybe required) for m209 and m211?

cncdrive wrote:As far as I remember this is done the same in Mach3, those functions are not separated, the THC on off and the M3 together controls the wait for ArcOK.

Yes, It's correct.
But I mean how M205/206 commands works. I think it makes no sense to enable/disable "wait for ArkOK" THC future on this commands. Just freeze torch (turn off automatic height control) and set attached hardware output pin for external devices. This also can applies to the other UCCNC THC futures (antidive and antidown) - freeze torch and set same hardware pin - OR logic.
All this comes down to use only M205/206 to freeze/defreeze torch from gcode. All other futures works constantly in parallel and can be turned on/off from the "configuration/IO setup".

Robertspark wrote: maybe with the neuron THC shad requires one of them linked to an output pin (optional setting... like m10/m11)..

Yes it's will be great!

The problem is, how does uccnc know the application is plasma? (Instead of a mill or lathe application setup)

Only by using the thc at present.... hence wait enable/ disable....

Yes, this is why we are here.