Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 608)

Cylindrical Grinding Fixed Cycles
Chapter 17
17-34
The following describes each of the cycle’s parameters.
X -- plunge end point
If in absolute mode (G90 active) then the value entered here is the X
coordinate of the plunge end point.
If in incremental mode (G91 active) then the value entered here is a signed
incremental value indicating the X distance from the start point to the end
point of the plunge motion. The start point is the coordinate of the X axis
prior to execution of the grinding cycle. The plunge end point
programmed with the X word must be a different position than the start
point of the cycle.
This parameter is “program modal,” meaning that it must be programmed
in the G89 block but will remain active once it is programmed. If not
programmed initially, the error “PLUNGE MOTION NOT
PROGRAMMED” results.
Z -- shoulder end point
If in absolute mode (G90 active) then the value entered here is the Z
coordinate of the shoulder grind end point.
If in incremental mode (G91 active) then the value entered here is a signed
incremental value indicating the Z distance from the start point to the end
point of the shoulder grinding motion. The start point is the coordinate of
the Z axis prior to execution of the grinding cycle.
R -- coarse plunge distance
R defines the coarse plunge distance and the clearance plane for the G89
cycle. If R is not programmed the coarse plunge phase of the cycle is not
performed. Any sign programmed with the X word is ignored. Always
program R as an incremental value. Measure R along the X axis from the
final plunge depth programmed with the X word. The R plane must not be
within the contours of the rough part. Programming an R plane greater
than the starting position (starting position between the R plane and the
final depth X) is valid and will not generate an error. The axes rapid to the
R plane and perform the coarse plunge at the feedrate F.
Important: If your system installer has installed a means of enabling a
micro-feed for this cycle, the micro-feed must be enabled before the axis
completes the initial rapid traverse.