Encoder Feedback Control (Pr. 144, Pr. 285, Pr. 359, Pr. 367 To Pr. 369) - Mitsubishi Electric FR-A720-0.4K Instruction Manual

4.25.6 Encoder feedback control (Pr. 144, Pr. 285, Pr. 359, Pr. 367 to Pr. 369)

V/F V/F V/F Magnetic flux Magnetic flux Magnetic flux
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.
Parameter
Name
Numbers
144 Speed setting switchover
Overspeed detection fre-
285
quency
*1
359 Encoder rotation direction
*2
367 Speed feedback range
*2
368 Feedback gain
*2
369 Number of encoder pulses
*2
*1 When exercising vector control with the FR-A7AP, this parameter changes to excessive speed deviation detection frequency. (For details, refer
to page 115)
*2 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. Under advanced magnetic flux vector control, the Pr. 81 Number of motor poles
setting is made valid and the Pr. 144 setting is invalid.
⋅ 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.
REMARKS
⋅ 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.
CAUTION
⋅ 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
enabled.)
Encoder rotation direction can be checked with the rotation direction display of the parameter unit.
Special operation and frequency control
Initial
Setting Range
Value
0, 2, 4, 6, 8, 10,
4 102, 104, 106,
108, 110
0 to 30Hz
9999
9999
0
1
1
0 to 400Hz
9999
9999
1 0 to 100
1024 0 to 4096
Description
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.
A
Encoder
Clockwise direction as viewed
from A is forward rotation
CCW
A
Encoder
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.
CW
4
361