HEIDENHAIN TNC 426 B, User Manual

Page: 235 / 362

8 Programming: Cycles
220
DATUM SHIFT (Cycle 7)
A datum shift allows machining operations to be repeated at various
locations on the workpiece.
Effect
When the DATUM SHIFT cycle is defined, all coordinate data is
based on the new datum. The TNC displays the datum shift in each
axis in the additional status display. Input of rotary axes is also
permitted.
ú
Datum shift: Enter the coordinates of the new datum.
Absolute values are referenced to the manually set
workpiece datum. Incremental values are always
referenced to the datum which was last valid — this
can be a datum which has already been shifted.
Example NC blocks:
73 CYCL DEF 7.0 DATUM SHIFT
74 CYCL DEF 7.1 X+10
75 CYCL DEF 7.2 Y+10
76 CYCL DEF 7.3 Z-5
Cancellation
A datum shift is canceled by entering the datum shift coordinates
X=0, Y=0 and Z=0.
Graphics
If you program a new BLK FORM after a datum shift, you can use
machine parameter 7310 to determine whether the BLK FORM is
referenced to the current datum or to the original datum.
Referencing a new BLK FORM to the current datum enables you to
display each part in a program in which several pallets are
machined.
Status Displays
■ The actual position values are referenced to the active (shifted)
datum.
■ All of the position values shown in the additional status display
are referenced to the manually set datum.
8.7 Coor
dinat
e
T
ransf
or
mation Cy
cles
Z
Z
X
X
Y
Y
Z
X
Y
IX
IY
kkap8.pm6 30.06.2006, 07:04 220
www.EngineeringBooksPdf.com