
OPERATION
B–63124EN/01
6. SAFETY FUNCTIONS
451
The detector on the machine automatically detects the positions of the
workpiece holders mounted on the carriage. Values representing the
detected positions are then set in the safety zone parameters.
# 1
F
# 2
# 3 # 4
Carriage
Detector (secured to the machine)
Fig. 6.5.5 (a)
The signal for detecting the position of the workpiece holders turns on and
off as workpiece holders #1 to #4 pass the detector as shown in Fig. 6.5.5
(a). The safety zone is determined from the signal. The position on the
X axis when the signal goes high is regarded as one end of a workpiece
holder, and the position when the signal goes low is regarded as the other
end.
Workpiece holder detection command format
G32X x
F f P p Q q ;
G32 is specified to detect the positions of workpiece holders. Before G32
can be specified, the workpiece holder position detector must be
activated.
Before detection is started, the X-axis move command must be specified
following address X. Either the positive or negative move direction is
allowed. If a positive move command is specified, the position at which
detection starts must be in the negative side with respect to workpiece
holder #1. Sufficient distance must be kept between the position at which
detection starts and workpiece holder #1 to enable stability of speed
before workpiece holder #1 is reached. Workpiece holders #1, #2, #3, and
#4 are detected in that order. If a negative move command is specified,
the workpiece holders are detected in the reverse order starting from #4.
The other conditions are the same as those used for a positive move
command.
The feed rate during detection is specified with F, in the same way as for
ordinary interpolation.
The position of a workpiece holder is obtained from the machine positions
indicated by the rising and falling edges of the workpiece holder detection
signal. There is a difference between the indicated machine position and
actual machine position because of an error such as a lag in the servo
system. This error must be compensated with numeric values following
addresses P and Q. The compensating value for the position on the rising
edge of the workpiece holder detection signal is set following address P,
and the compensating value for the position on the falling edge is set
following address Q.
The lag in the servo system is obtained from the following equations:
6.5.5
Automatic Setting of
the Safety Zone