Tool switch below surface

Hi,
Is there a way to set a negative height to the tool switch in gmoccapy?
I mounted a switch below the work surface of my machine.
Only in the settings tab in gmoccapy i cant enter a negative value.

Thanx

thanks a lot for your explanation. Its great how you made all steps quite clear.

I still have an odd problem. All seems to run well, but the Z zero is now set to the machine bed, not to the top of the workpiece.
I did enter the block height before probing.
When I enter 0 as block height it sets the G54 Z-value to -145 (travel of Z is from 0 to -145)

I broke a tool so thats too bad.

After that I changed the probe to above my machine bed to see if that worked. I forgot to edit the INI file- probe positions.
Bugger, broke a part of my z-axis.

I will call it a day for now, tomorow repair my mill and I will see from there than

Hallo Clement,

I do test such stuff with a piece of Styropor, hope in Englisch the Material is called so also. And have one Hand on the estop switch!!

I will check the code for possible errors with negativ values. Could you please mention what values you enter and give a step by step instruction to reproduce your problem?

Norbert

Thanks for the support. I am currently busy repairing my machine. Hopefully it Will be up and running this evening. I'll try to reproduce the error when done.

I think air is the best material to try next time.

well I repaired my z-axis, all seems to be fine for now.

I have been playing around a lot with the different offsets etc.
The workpiece is placed in the G56 location.
In the header of my ngc file no location was specified.

The steps I took when it went wrong:
Start Linuxcnc (G54)
Set block height to 12mm. (now I know this is applied as an offset to G54)
MDI -> G56

press run. (it runs at a different Z offset all together)

Both errors I had, where on my side.

I did notice 2 other behaviors I cant quite understand.
1) if I have a ngc file with two different offsets eg G54 & G56, the offset of the block height is only applied to the one which is currently active. Looking in the direction of the Y-axis in the preview window, it is clear the Z-height changes when going to the other fixture.

2) I was running a program at Z= -3. When I press the big red button "Stop the running Program" the Z-value immediately changes to Z=9.
In the offsets table the tool offset for Z is zero. Before running the program the tool offset was 12.

1) if I have a ngc file with two different offsets eg G54 & G56, the offset of the block height is only applied to the one which is currently active. Looking in the direction of the Y-axis in the preview window, it is clear the Z-height changes when going to the other fixture.

Do you think it is better to set the Blockhight to all fixtures? It would be possible to apply the blockhight each time the Coordinate system changes. But that could have side effects too.

I was running a program at Z= -3. When I press the big red button "Stop the running Program" the Z-value immediately changes to Z=9.
In the offsets table the tool offset for Z is zero. Before running the program the tool offset was 12.

Very strange, as you do not use any G43 in your code. I will check on this with your sample and also check if integrate enter negative values makes sense..

Norbert

It could be conveniant to set the block height in multiple references when milling the same part out of à big sheet