
B–63503EN–1/01
9. SPINDLE SPEED FUNCTION
373
[Classification] Input signal
[Function] The SAR signal initiates cutting feed. In other words, if the signal is
logical 0, cutting feed will not start.
[Operation] Generally, this signal is used to inform the CNC that the spindle has
reached the specified speed.
For this purpose, the signal must be set to 1 only after the actual speed of
the spindle has reached the specified speed.
Setting parameter No. 3740 with a wait time before the start of checking
the SAR signal inhibits cutting feed from starting under a condition of
SAR = 1 specified before the change of the spindle command.
To use the SAR signal, it is necessary to set bit 0 (SAR) of parameter No.
3708 to 1.
The CNC checks the SAR signal under the following conditions:
a. Bit 0 (SAR) of parameter No. 3708 is set to 1.
b. Before starting distribution of the first feed (move command) block
after shifting from the rapid traverse mode to the cutting feed mode.
This checking is performed after the time set by parameter No. 3740
has elapsed after the feed block is read.
c. Before starting distribution of the first feed command block after an
S code is commanded. The wait time for checking is the same as in
item b.
d. When an S code and feed are programmed in the same block, the S
code (or command output to the spindle) is output, and the SAR signal
is checked after a fixed time elapses. If the SAR signal is set to “1”,
feed begins.
CAUTION
According to the conditions of item d above, note that if the
circuit is so designed that SAR is turned to “0”
simultaneously with the output of an S code and the change
of spindle speed is gated with DEN signal, the operation will
stop. That is, the spindle speed does not reach the
commanded speed because the CNC is waiting for the DEN
signal and distribution is not started because the CNC is
waiting for the SAR signal.
Spindle speed arrival
signal SAR <G029#4>