
B–61863E/15
5. FUNCTIONAL INSTRUCTIONS
PMC SEQUENCE PROGRAM
333
(i) Spindle control with automatic gear selection
This functional instruction uses spindle speed data (32–bit binary
data) and the maximum spindle speeds set in parameters GR1 to
GR4 of this functional instruction to select a gear, calculate the
spindle motor rotation command for that selected gear, and output
the result to the control data address.
Based on this output information, the sequence program must
perform gear switching as necessary and output the rotation
command to the spindle motor.
Spindle motor
rotation
command
Spindle speed
SPCNT
Spindle control
Information of GR1 to GR2
ȡ
ȧ
ȥ
ȧ
Ȣ
ȣ
Ȧ
Ȥ
(ii) Spindle control with direct gear selection
When direct gear selection is set, this functional instruction does
not perform gear selection. A gear to be used is selected by the
sequence program. The target gear must be set at the control data
address, which is a parameter of this functional instruction, using
the sequence program.
According to the set gear, the functional instruction calculates and
outputs a spindle motor rotation command. In this case, the
spindle motor rotation command has a linear relationship with the
spindle speed. The line for the selected gear is assumed to extend
to its lower limit (indicated by a dotted line). See Fig.5.63.1.
Spindle motor
rotation
command
Spindle speed
SPCNT
Spindle control
Information of GR1 to GR2
ȣ
Ȧ
Ȥ
ȡ
ȧ
ȥ
ȧ
Ȣ
The spindle motor speed can be clamped at the upper and lower
limits also with direct gear specification. When the CNC
performs constant surface speed control, spindle control with
direct gear specification is generally performed.