Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 404)

Axis Motion
Chapter 12
12-32
Figure 12.19
Automatic Return From Machine Home, Results of Example 12.17
X
Z
50 100 150 200
50
100
150
200
N10
N20
N30
N30
N40
Machine home
12157-I
Important: When a G29 is executed, offsets and/or compensation is
deactivated on the way to the intermediate point and are re-activated when
the axis moves from the intermediate point back to the point indicated in
the G29 block.
A G27 causes the control to move the axes at rapid directly to the machine
home position. Only the axes included in the G27 block are moved.
G27 X__ Z__;
The value entered with the axis name in the G27 block must be the
machine home coordinate for that axis. If it is not, no axis motion takes
place and the control issues the error message:
“INVALID ENDPOINT IN G27 BLOCK”
Aside from this endpoint check, the only difference between a G27 block
and a G00 block requesting a move to the machine home coordinates is
that the G27 is not modal. If G01, G02, or G03 modes were active before
the G27 was executed, they are reactivated immediately after the G27
block is completed.
G27 block commands are usually given after wheel offset modes have
been cancelled.
If an attempt is made to execute a G27 before the axes have been homed,
the control enters cycle stop and the following error message occurs:
“MACHINE HOME REQUIRED OR G28”
12.4.4
Machine Home Return
Check (G27)