SJ700
2
Inverter
Oper
ati
ons
and Monitor
ing
4–37
Speed Servo ON
The servo-ON function allows you to set the inverter in a speed-servo-lock state with an
intelligent input during operation. This function is available when A044=05
vector control with
sensor
for the characteristic V/f curve.
To use the servo-ON function, assign option code 54 to an intelligent input. After making the
input assignment, the inverter will accept an operation command only when the [SON] terminal
is ON.
If the [SON] terminal is turned OFF during inverter operation, the inverter output enters FRS
mode (free-run stop). If the [SON] is turned ON again, the inverter restarts the motor according
to function B088, Restart Mode After FRS.
The inverter does not allow [SON] terminal assignment and [FOC] (forcing function) assign-
ment at the same time. If both are assigned, the [FOC] has priority (operates normally) and the
[SON] function is not available.
Current Forcing
The current forcing function applies an excitation current to pre-build magnetic flux in the
motor. The forcing function is available when one of the following vector control modes is
configured for use at the inverter output:
• A044 = 03 sensorless vector control
• A044 = 04 0Hz-range sensorless vector control
• A044 = 05 vector control with sensor
To use current forcing, assign option code 55 to an intelligent input terminal. After making the
input assignment, the inverter will accept an operation command only when the [FOC] terminal
is ON.
If the [FOC] terminal is turned OFF during inverter operation, the inverter output enters FRS
mode (free-run stop). If the [FOC] is turned ON again, the inverter restarts the motor according
to function B088, Restart Mode After FRS.
Opt. Code
54
Symbol
[SON]
Valid for
Inputs
[1] to [8]
Required
Settings
A044
Default
terminal
Requires
config.
Output
frequency
Servo-ON [SON]
FW/RV
Free-run stop
t
0
Speed-servo lock states
Restart after FRS (B088)
Inverter does not follow FW/RV
command because [SON] is OFF
Opt. Code
55
Symbol
[FOC]
Valid for
Inputs
[1] to [8]
Required
Settings
A044, A244
Default
terminal
Requires
config.
Output
frequency
Current forcing [FOC]
FW/RV
Free-run stop
t
0
Excitation current flows
Restart after FRS (B088)
Inverter does not follow FW/RV
command because [FOC] is OFF