4.25.6 Encoder feedback control (Pr. 144, Pr. 285, Pr. 359, Pr. 367 to Pr. 369)
This controls the inverter output frequency so that the motor speed is constant to the load variation by detecting the
motor speed with the speed detector (encoder) to feed it back to the inverter.
Option FR-A7AP is necessary.
Speed setting switchover
(Speed deviation excess
Encoder rotation direction
Speed feedback range
Number of encoder pulses
When exercising vector control with the FR-A7AP, this parameter changes to excessive speed deviation detection frequency. (For details, refer
to page 116)
The above parameters can be set when the FR-A7AP (option) is mounted.
(1) Setting before the operation (Pr. 144, Pr. 359, Pr. 369 )
⋅ When performing encoder feedback control under V/F control, set the number of motor poles in Pr. 144 Speed setting
switchover according to the motor used. Because the number of motor poles is set in Pr. 81 Number of motor poles
under advanced magnetic flux vector control, it is unnecessary to change Pr. 144.
⋅ Set the rotation direction and the number of encoder pulses of the encoder using Pr. 359 Encoder rotation direction and
Pr. 369 Number of encoder pulses.
⋅ When "0, 10, 110" is set in Pr. 144 and run the inverter, error E.1 to E.3 occurs.
⋅ When "102, 104, 106, 108" is set in Pr. 144, the value subtracting 100 is set as the number of motor poles.
⋅ Setting Pr. 81 Number of motor poles changes the Pr. 144 setting automatically. However, changing the Pr. 144 setting will not
change the Pr. 81 setting automatically.
⋅ If the number of motor poles is wrong, control at correct speed can not be performed. Always check before operation.
⋅ Encoder feedback control can not be performed when the setting of encoder rotation direction is wrong. (Inverter operation is
Encoder rotation direction can be checked with the rotation direction display of the parameter unit.
0, 2, 4, 6, 8, 10,
102, 104, 106,
0 to 30Hz
0 to 400Hz
0 to 100
0 to 4096
Special operation and frequency control
Set the number of motor poles when performing
encoder feedback control under V/F control.
If (detected frequency) - (output frequency) > Pr. 285
during encoder feedback control, the inverter alarm
(E.MB1) is provided.
Overspeed is not detected.
Clockwise direction as viewed
from A is forward rotation
Counter clockwise direction as
viewed from A is forward rotation
Set the region of speed feedback control.
Encoder feedback control is invalid
Set when the rotation is unstable or response is slow.
Set the number of pulses of the encoder.
Set the number of pulses before multiplied by four.