Quote from: fredeflint on October 18, 2016, 11:33:14 PM

ftr it does not look like you can feed hold a g4 command.

Quote from: stirling on October 17, 2016, 05:45:40 AM

By definition, feedhold only works when there's movement TO feedhold.

yes, and excuse my ignorance as i ma not a mach3 expert,  but it is not immediately clear to me why a pause in a sequence of moves would not be considered movement. probably i don't understand the logic behind what feed hold is really used for in practice since im not much of a machinist, but if i had a piece of gcode that had a g4 in a complicated sequence i wanted to pause, i might expect that feedhold will pause the gcode execution. or at least pause at the subsequent movement after the g4. obviously it does not as found empirically.

anyway thank you again for your help, it is greatly  appreciated and saved me a lot  of time.

s

yes, and excuse my ignorance as i ma not a mach3 expert,  but it is not immediately clear to me why a pause in a sequence of moves would not be considered movement. probably i don't understand the logic behind what feed hold is really used for in practice since im not much of a machinist, but if i had a piece of gcode that had a g4 in a complicated sequence i wanted to pause, i might expect that feedhold will pause the gcode execution. or at least pause at the subsequent movement after the g4. obviously it does not as found empirically.

I agree with you and what you say but Mach3 operates the way it does and that is the way we must learn to use it.

Tweakie.

Quote

yes, and excuse my ignorance as i ma not a mach3 expert,  but it is not immediately clear to me why a pause in a sequence of moves would not be considered movement. probably i don't understand the logic behind what feed hold is really used for in practice since im not much of a machinist, but if i had a piece of gcode that had a g4 in a complicated sequence i wanted to pause, i might expect that feedhold will pause the gcode execution. or at least pause at the subsequent movement after the g4. obviously it does not as found empirically.

I agree with you and what you say but Mach3 operates the way it does and that is the way we must learn to use it.

Tweakie.

ya that is my experience with it so far, it does work, but you just have to know all it's peculiarities.  lots of good info in the forum though at least. i pretty much figured out everything else i needed else from reading through it.

it is not immediately clear to me why a pause in a sequence of moves would not be considered movement.

I understand where you're coming from but try not to think of it as a PAUSE in GCode execution. It's a HOLD in axis movement i.e. a HOLD in FEED. - does that help?

probably i don't understand the logic behind what feed hold is really used for in practice

You can hit STOP at any time and that is exactly what will happen. i.e. stop movement, stop gcode execution - stop everything.

However, if you STOP whilst moving you may loose position. Therefore, there's a need for another way of stopping in the case where there's movement that doesn't cause a position loss. That is FEED HOLD. - does that help?

Also, this is not peculiar to Mach - this (AFAIK) is how it works generally across all CNC controllers.

ya it's all good, thank you for that explanation,  i think my post came off as complain-y, everything is good. at first i was not sure mach3 could even do a pause as i wanted, so i guess that was really part of my original question as well.

I also realized  yesterday a less elegant solution. I could have just  disabled the spindle on/off relays setting and simply toggled the spindle on or off  on a gpio on the controller card, one that isnt assigned to the "spindle relay" in mach 3, likely this would not get changed in a stop command. Then toggle it in a  macro instead of using m3/m5. this is less desirable cause i have to change the setup and then my old gcodes need to be modified etc and as you say with STOP you may lose position etc etc.

"Optional" stop as you suggested does not seem to stop the spindle. Again not intuitive to me but i will take it, since its exactly what i want

Thanks again for your input.