Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 686)

Skip, Gauge, and Probing Cycles
Chapter 27
27-12
The purpose of this cycle is to provide a means to measure the amount that
a part is out of parallel (or rotated) with a selected axis through the use of a
touch probe. Note that the currently active plane (G17, G18, or G19) must
be the same plane in which probe motion is to occur in and must be active
before the probing cycle block is executed.
Format for the G38.1 code is as follows:
G38.1 X__ Y__ I__ J__ R__ D__ E__ F__;
Where : Is :
X Any valid axis name followed by the coordinate position of the first measuring
point on that axis. May be an absolute or incremental, signed value. Being the
first axis word in the G38.1 block indicates that this axis is the one from which
measurements are to be taken. The G38.1 probing cycle will determine how
much the part is out of parallel with this axis
Y The name of any axis that is perpendicular to the first axis in the G38.1 block.
May be an absolute or incremental, signed value. Parallelism will be measured
by moving the probe along this axis to the edge of the part. The value entered
with this parameter defines the expected position on this axis where the probe
will hit the edge of the part.
I
(integrand of
first axis in
G38.1 block)
The incremental signed distance between the first and second probe hits. This
incremental distance is measured along the first axis programmed in the G38.1
block. In this manual I is the integrand word for the X axis. The integrand word
for an axis is determined in AMP.
J
(integrand of
second axis
in G38.1
block)
The estimated amount the part is out of parallel. J is an incremental, signed
distance. J is added to the coordinate value entered with the second axis in the
G38.1 block for the second probe hit only. The net result is to shift the tolerance
band (programmed with the D word) by the amount J.
R The incremental unsigned approach distance. This parameter determines the
distance the second axis in the G38.1 block travels at the E feedrate when
probing towards the part. After this distance is reached the probe slows to the F
feedrate. This parameter is optional. If not entered, the control will default to the
value entered in the probing table discussed in section 27.5.
D The tolerance band distance. The value entered for D defines a band on both
sides of the expected endpoint entered with the Y parameter. Enter a value for
this parameter defining a tolerance distance on either side of the expected probe
triggering point (Y above). This parameter is optional, but must have a positive
value if programmed. If not programmed, the control will default to the value
entered in the probing cycle parameter table discussed in section 27.5.
E The approach feedrate. Enter a value for this parameter that defines the feedrate
used to reach the approach distance (R). This parameter is optional. If not
entered, the control will default to the value entered in the probing cycle
parameter table discussed in section 27.5.
F The probe feedrate. Enter a value for this parameter that defines the feedrate at
which the probe is to move after passing the point defined by the R parameter.
The probe continues on at this feedrate until contact has been made with the
edge of the part or the tolerance band is exceeded. This parameter is optional.
If not entered, the control will default to the value entered in the probing cycle
parameter table discussed in section 27.5.
27.5
Parallel Probing Cycle
(G38.1)