
17.PMC CONTROL FUNCTION B-63943EN-1/02
- 1926 -
NOTE
1 The following feedrate error can occur:
(a) With the speed command based on PMC axis control, a servo motor speed is
specified as a feedrate. So, in order to specify a feedrate for an axis when a
gear is used between the axis and servo motor, the desired feedrate for the
axis needs to be converted to a servo motor speed. A feedrate must be
specified using an integer, so that when it is converted to a servo motor speed,
a rounding error can occur.
(b) The minimum unit of feedrate is given by the expression below. An integer
must be specified. No finer value may be specified.
Fmin = P ÷ 1000 (mm/min)
A calculation is made according to IS-B.
Fmin: Minimum feedrate unit
P : Number of pulses per revolution of a detector for speed feedback
A speed is specified according to the expression below.
F = N × P ÷ 1000 (mm/min)
A calculation is made according to IS-B.
F : Speed command (integer)
N : Servo motor speed (min
-1
)
P : Number of pulses per revolution of a detector for speed feedback
2 In the speed command mode, a speed after acceleration/deceleration is specified
for the servo control section. At this time, a position control loop gain is invalid.
3 Machine lock is disabled for the speed command.
(17) Torque control ( 11h )
This command performs a continuous feed operation based on torque
control.
With this command, position control on a PMC control axis can be
switched to torque-based control. The servo motor outputs torque
exactly as specified by the NC.
Axis control block data
Signal
abbreviation
Signal address
(group 1)
Data
EC0g to EC6g G143.0 to .6 Torque control command (11h)
EIF0g to
EIF15g
G144,145 Maximum feedrate
EID0g to
EID31g
G146 to 149 Torque data
Gear
Motor
xis
(b)
Speed command
mpli-
ier
Detec-
to
(a)