Absolute readout & tool length offset

[leeroy]

G'day all

I'm currently the operator of an Extron 4 axis machining center. It has the Itri/mirl m2000 control (Fanuc based). After 12 months on this machine i pretty much have it sorted out.. just one thing has bothered me.

As we have a 20 tool changer and most jobs use more than one tool i set the tool lengths off the table surface. The trouble is that the control dosn't allow for the Tool Length offset (G43) in the Absolute or Relitive co-ordinates readout. If for example my tool length for tool one is 145.5 mm and i use the code
G43 H1
G0 Z0

When the machine reaches Z0 the readout will display Z145.5 instead of Z0. While i have been able to use the machine quite sucessfully it would make life much easier if i could see exactly what the z axis is doing without having to do a calculation on my hand calculator to ge the true Z position.

Does anyone know how i can change this? Is the some parameter in the control that allows for this? Or is there another method of setting up my tools?

Thanks
Cheers
Leeroy

[HuFlungDung]

Does this control only have one screen for position? It sounds as though it is showing you machine position in the machine's G53 coordinate system.

Are you using a work offset in your programming? Is there a position screen that makes reference to "work" coordinates or something like that?

[dcoupar]

Do you have any idea of which Fanuc it's based on? For a 21iM, I'd look at Parameter 3104 bit 6.

[fuzzyracing1967]

It may be in the program itself.

G0 G43 X4 Y3 Z2 H14 M3 S1000
G92 X4 Y3 Z2 M8
G0 Z0

If you don't call out the postion again after the G92 it will do what Leeroy is saying.Anyway that is how the meldos control works on are comet.

[leeroy]

Thanks for the replies guys..

Yes i am using a work offset, mostly G54. Under the "Position" display i only get Absolute, Relative, Machine and Distance to go readouts. There is no reference to "work" coordinates at all.
I have't used G92 before. A typical program looks like this.

M6 T1
T0
G0 G90 G54 X0 Y0
G43 H1 Z50 M8
M3 S5000
G0 Z10
G1 Z-1 F500
X25
Z0
G0 Z200 M9
M5
M6 T0
M30


The manuals that came with the machine cover the basics and do list some of the internal parameters but there's nothing about tool length offset. And as usual they are a very poor translation.
Even a google search on the controll revealed no info at all.
I did read about the fanuc parameters on another thread. The control is PC based under DOS so i'll have a look for any text or doc files there but i doubt it.

Cheers
Leeroy