G43 Tool Offset question

[sbrunton]

I'm having an issue when using tool offsets. I have tool number 1 defined in the tool file with a length of 1.975". When I issue G43 H1 it sets the tool offset to 1.975 and subtracts the length from the current Z position.

The problem is that it continues to subtract 1.975" on every machine movement until I issue G49 to cancel the tool offset. If I explicitly provide a Z value it doesn't do this. So,

G0 X0 Z0
G0 X1 Z0
G0 X2 Z0
moves one inch to the right on the second and third lines

G0 X0 Z0
G0 X1
G0 X2
moves one inch to the right and 1.975” down on the second and third lines

I noticed there’s a similar bug reported on the Sourceforge site, although that reported that the tool was moving downwards more than the tool length.

Am I doing something wrong in the GCode? I am issuing T1M6 previously, although I don’t believe it has any bearing on the tool offset.

Is this a bug in EMC? If so, does anyone have a good workaround? I could use the coordinate systems to compensate for the tool lengths, but then I’d be coding them into my programs.

Thanks,

Steve

[HuFlungDung]

Sounds like a bug in the software to me. You might be able to define the nature of the bug more distinctly, since it may have to do with a mix-up between incremental and absolute positioning. You might play around with setting G90 mode in the controller before you enter or call out the length offsets, just in case it misinterprets the length offset as an incremental movement.

[sbrunton]

Thanks for you reply.

The example above is in absolute mode.

In incremental mode it also keeps subtracting the tool offset from Z on each move, but it does this even if I specify a Z coordinate. So typing G0 Z0 makes the head lower by the tool offset every time.

I've tried executing the G43 in both modes and it doesn't make a difference.

[Dan Falck]

Could you post this on the emc mailing list? I know that there was a bug introduced in one of the recent releases, but I think that it's been fixed.

Dan