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7.2 Speed control mode
This mode allows for accurate, smooth control of the rotation speed and direction of the servo motor.
Analog speed can be commanded with LECSB.
* To set [PC**], set parameter write inhibit [PA19] to "000C".
7.2.1 Operation instruction
When the signals ST1 and ST2 turn on, the servo motor rotates.
An operation example of the speed control mode is shown below.
Speed setting
Speed command and speed
The servo motor is run at the speeds set in the parameters or at the speed set by the applied voltage of the
analog speed command (VC).
The relationship between the analog speed command (VC) applied voltage and the servo motor speed is shown
below.
Rated speed is achieved at 10V with initial setting. The speed at 10V can be changed using parameter
No.PC12.
Forward rotation (CCW)
Reverse rotation (CW)
-10
Rated speed [r/min]
CCW direction
0
+10
VC applied voltage [V]
CW direction
Rated speed
Speed [r/min]
The following table indicates the rotation direction according to forward rotation start (ST1) and reverse rotation
start (ST2) combination.
(Note 1) Input device
(Note 2) Rotation direction
ST2
ST1
Analog speed command (VC)
Internal speed
commands
Polarity
0V
Polarity
0
0
Stop
(Servo lock)
Stop
(Servo lock)
Stop
(Servo lock)
Stop
(Servo lock)
0
1
CCW
Stop
(No servo lock)
CW
CCW
1
0
CW
CCW
CW
1
1
Stop
(Servo lock)
Stop
(Servo lock)
Stop
(Servo lock)
Stop
(Servo lock)
Note 1. 0: off
1: on
2. If the torque limit is canceled during servo lock, the servo motor may suddenly rotate according to position deviation with respect to the
command position.
In general make the connections shown below.
ST2
DOCOM
P15R
VC
LG
SD
ST1
Japan resistor
RRS10 or equivalent
(Note)
2k
2k
Servo amplifier
Driver
Forward rotation start
Peverse rotation start