G-code question

[acourtjester]

I have a question about the post processor for GRBL THC with scriber. There are 2 things that don't make sense to me (many other really).
One is in the attached image of the G-code it seems the 2 lines near the top I think are not needed. After the probe command it zeros out the DRO (G92) then moves to Z0.059 and clears the DRO again then moves to Z0.160 for the pierce. Why the move to 0.059???? then add the distance of 0.160 to it, or don't zero out the DRO between them.
Next other cut starts do not have the probe command before the pierce action. My way of thinking is you should probe at the start of each cut operation.

gcode question.JPG

[sonbakler]

I don't see the point in that either. I am sure it is accounting for something but I can't figure out what. Anything in the settings prior to posting that has the value 0.059" in it? Is it accounting for Z axis slop or limit switch offset? Would make sense that it is Z axis slop or switch offset since it only does it once after the initial probe.

[acourtjester]

That could be it as it is using a G38 for touch off, this was for GRBL controller. I use G31 with ohmic sensor so only one move to pierce height with another controller (UCCNC).

[adbuch]

I have a question about the post processor for GRBL THC with scriber. There are 2 things that don't make sense to me (many other really).
One is in the attached image of the G-code it seems the 2 lines near the top I think are not needed. After the probe command it zeros out the DRO (G92) then moves to Z0.059 and clears the DRO again then moves to Z0.160 for the pierce. Why the move to 0.059???? then add the distance of 0.160 to it, or don't zero out the DRO between them.
Next other cut starts do not have the probe command before the pierce action. My way of thinking is you should probe at the start of each cut operation.
gcode question.JPG

For Hypertherm - 0.059" is pretty close to 0.060" - which is the recommend cut height for most setups. Since I am not familiar with your setup, I don't really know what is happening there. Perhaps it somehow has some settings reversed or there is a value set into the wrong parameter. Is the "probing" your ohmic sensing? Perhaps it is only probing once and then using "from previous cut height" for the remaining pierce/cuts.
David

[acourtjester]

I am not using this GRBL Post Processor I was just looking at it, and saw that which I questioned. Just trying to learn if there was a valid reason of a typo involved. I think Sonbakler gave a very reasonable answer of it being the backlash of a floating head switch. With a ohmic sensor there is almost zero backlash so no correction is needed.

[adbuch]

I am not using this GRBL Post Processor I was just looking at it, and saw that which I questioned. Just trying to learn if there was a valid reason of a typo involved. I think Sonbakler gave a very reasonable answer of it being the backlash of a floating head switch. With a ohmic sensor there is almost zero backlash so no correction is needed.