
B–63833EN–1/02
9. SPINDLE SPEED FUNCTION
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The S command specifies the spindle speed entered from machining
programs, etc. for the CNC.
For constant surface speed control (during G96 mode), the CNC converts
the specified surface speed to the spindle speed.
In the M series with bit 4 (GTT) of parameter No. 3706 = 0 without the
constant surface speed control, the CNC specifies the gear stage for the
desired spindle speed to the PMC according to parameter No. 3741, 3742,
and 3743, and the S command.
(GR3O, GR2O, GR1O <F034#2, #1, #0>)
With the spindle serial output or spindle analog output, the spindle control
function in the CNC converts the S command value to the output value
for the spindle motor. In addition, the S code/SF signal’s response to S
command input changes as follows, compared with the case where gear
change and constant surface speed control are not used.
M series → Outputs the S code.
The SF signal is output only when the CNC directs the PMC
to change the gear.
T series → Outputs neither S code nor SF signal.
(This is because the S code is not always the spindle speed
when the constant surface speed control option is used.)
If you use the S code for processing in the PMC ladder, you must specify
parameters related to parameter No. 3705.
This signal sets the S command value in the CNC to 0. If the CNC is
specifying the spindle output (see descriptions on the SIND signal), this
signal sets the speed command for the spindle to 0.
Even if the spindle stop signal is not used, the signal must be set to logical
1 for the CNC to perform spindle speed control.
If the spindle orientation signal is logical 1 and the spindle stop signal is
logical 0, the spindle rotates in the direction specified by bit 5 (ORM) of
parameter No. 3706 at a constant speed specified by parameter No. 3732.
Because the spindle rotates at a constant speed regardless of the gear
stage, this signal can be used to rotate the spindle to drive the stopper or
pin during mechanical spindle positioning.
For the M series, setting parameter GST (bit 1 of parameter No. 3705)
enables the spindle motor to rotate at a constant speed at an M type gear
shift. This function can be used for gear shifting because it maintains a
constant speed of the gear change mechanism.
This signal specifies an override of 0% to 254% for the specified S value
for spindle control.
However, the spindle speed override function is disabled when the CNC
is in the following state:
Tapping cycle (M series : G84, G74 T series : G84, G88)
Thread cutting (M series : G33 T series : G32, G92, and G76)
When the spindle speed control is performed but the spindle speed
override is not used, set the override value to 100%.
D S command
D S code/SF signal output
D Spindle stop signal
(*SSTP)
D Spindle orientation
signal (SOR)
D Spindle speed override
signal (SOV00 to SOV07)