Encoder Feedback Control (Pr. 144, Pr. 285, Pr. 359, Pr. 367 To Pr. 369) - Mitsubishi Electric FR-B-750 to 75K Instruction Manual

Special operation and frequency control

4.20.5 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.
Parameter
Name
Numbers
144 Speed setting switchover
Overspeed detection
frequency
285
(Speed deviation excess
detection frequency)
359 Encoder rotation direction
*2
367 Speed feedback range
*1
368 Feedback gain
*1
369 Number of encoder pulses
*1
*1 The above parameters can be set when the FR-A7AP (option) is mounted.
*2 The setting range differs according to the inverter capacity. (22K or less/30K or more)
(1) Setting before the operation (Pr. 144, Pr. 359, Pr. 369 )
⋅ When performing encoder feedback control under FR-B series, set the number of motor poles in Pr. 144 Speed setting
switchover according to the motor used. Under FR-B3 series, 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.
242
Initial Setting Range
Value FR-B FR-B3
0, 2, 4, 6, 8, 10, 102,
4
104, 106, 108, 110

0 to 30Hz
9999

9999
0
1
1
0 to
0 to 120Hz/
0 to 60Hz
9999 120Hz
*2
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