NCT Group NCT 990T - Manual (Page 79)

7.2.2 Tool Length Offset Measurement inside the Machine
79
If No Work Zero Point Offset Measurement had Taken Place Previously
If no work zero point offset had
taken place previously, the ap-
propriate work offset of the se-
lected coordinate system is zero
(M
x
=0, M
z
=0). The coordinate
values measured after cutting
and entered to control at ad-
dresses X and Z: x
0
, z
0
. The con-
trol calculates the tool length
with the help of the relation, dis-
cussed for work zero point off-
sets. The tool length offsets re-
sulted contain the X- and Z-di-
rection work zero point offsets,
as seen on the diagram.
x
c
= x – x
0
– M
x
z
c
= z – z
0
– M
z
If Work Zero Point Offset Measurement had Taken Place Previously
After entering the coordinates
the tool length is calculated with
the help of the following equa-
tion:
x
c
= x – x
0
– M
x
z
c
= z – z
0
– M
z
where
– x
c
z
c
: length offset calculated
by the control
– x, z: reference position of the
tool holder in the
machine coordinate sys-
tem(excluding length
offset)
– x
0
, z
0
: data entered to coordi-
nates X and Z, the
known size of the
workpiece
– M
x
, M
z
: Work zero point offset value in the selected coordinate system.
In this case the tool length equals to the tool overhang, as seen on the diagram.
L Note:
Values x and z of the above equation differ to position seen on position display G53, if tool
length compensation has been called (Tnnmm). In values "x, z" the called length offset is
never taken into account. Therefore before measuring it is useful to delete tool length by
means of command Tnn00, however this only makes position display more understandable.