
11.SPINDLE SPEED FUNCTION B-63943EN-1/02
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M
For the machining center system, setting parameter GST (bit 1 of
parameter No. 3705) enables the spindle motor to rotate at a constant
speed. This function can be used for gear shifting because it maintains
a constant speed of the gear change mechanism.
- Spindle speed override signal (SOV00 to SOV07)
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%.
- Processing for gear changing
Although the S command contains the spindle speed, the object that is
actually controlled is the spindle motor. Therefore, the CNC must
have some provision to detect the gear stage between the speed and
spindle motor.
There are two types of gear selection methods:
M type
The CNC selects a gear stage according to the range of speed for each
gear stage previously specified in a parameter, as directed by the S
command, and informs the PMC of the selected gear stage (one of the
three gear stages ) using the gear select signal output (GR3O, GR2O,
GR1O).
Also, the CNC outputs the spindle speed based on the selected gear
stage (output as the gear select signal).
T type
The gear stage to be used is determined on the machine side, and the
gear stage is input using the gear selection signals (GR1 and GR2)
(one of the four gear stages).
The CNC outputs the appropriate speed command for the selected
gear range.
- Selection of gear change system
M
The machining center system can use either M or T type.
M type → Without constant surface speed control option, and bit 4
(GTT) of parameter No. 3706 = 0
T type → With constant surface speed control, or bit 4 (GTT) of
parameter No. 3706 = 1