Encoder Feedback Control - Mitsubishi Electric 800 Series Instruction Manual

5.16.14

Encoder feedback control

By detecting the rotation speed of the motor with the speed detector (encoder) and feeding it back to the inverter,
output frequency of the inverter is controlled to keep the speed of the motor constant even for the load change.
Vector control compatible option is required.
Pr.
144 Speed setting
M002 switchover
285 Overspeed detection
H416 frequency
359 852
Encoder rotation
C141 C241
direction
 
367
Speed feedback range
G240

368
Feedback gain
G241

369 851
Number of encoder
C140 C240
pulses
 

The speed deviation excess detection frequency is used when vector control compatible option is mounted and vector control is performed.
(For the details, refer to

These parameters are available when vector control compatible option is installed.

The parameter number is the one for use a Vector control compatible option. (Pr.369 is applicable for the FR-A8AP and FR-A8AL.)

The parameter number is the one for use with the control terminal option (FR-A8TP).
Setting before operation (Pr.144, Pr.359, Pr.369)
• When driving with V/F control and the encoder feedback control, set the number of motor poles in Pr.144 Speed setting
switchover in accordance with the applied motor. During Advanced magnetic flux vector, the Pr.81 Number of motor
poles setting is used, so the Pr.144 setting does not need to be changed.
• Using Pr.359 Encoder rotation direction and Pr.369 Number of encoder pulses, set the rotation direction and the
number of pulses for the encoder.
NOTE
• When the inverter is operated with Pr.144 = "0, 10, 12, 110, 112", it will cause E.1 to E.3.
• When set to Pr.144 = "102, 104, 106, 108", number with 100 subtracted will be set as the number of poles.
• When Pr.81 is set, setting value for Pr.144 will be automatically changed, but even if Pr.144 is changed, Pr.81 will not
automatically change.
• Control with correct speed is not possible if the number of poles for the applied motor is incorrect. Make sure to confirm
before operation.
• Encoder feedback control is not possible when the rotation direction setting of the encoder is incorrect. (Operation of the
inverter is possible.)
Confirm with the rotation direction indicator on the parameter unit.
Initial
Name
value
0, 2, 4, 6, 8,
10, 12, 102,
4
104, 106, 108,
110, 112
0 to 30 Hz
9999

9999
0
100
1
1
101
0 to 590 Hz
9999
9999
1 0 to 100
1024 0 to 4096
page 179.)
V/F V/F V/F Magnetic flux Magnetic flux Magnetic flux
Setting
range
Set the number of motor poles for the operation by V/F
control and the encoder feed control.
When the difference between the detected frequency and
the output frequency exceeds the set value at the time of
encoder feedback control, an inverter fault (E.MB1) is
generated.
Overspeed detection disabled.
Set when using a motor for
which forward rotation
(encoder) is clockwise
(CW) viewed from the shaft
CW
Set when using a motor for
which forward rotation
(encoder) is
counterclockwise (CCW)
viewed from the shaft
CCW
Set the range of speed feedback control.
Disables encoder feedback control
Set when the rotation is unstable or response is slow.
Set the number of encoder pulses output.
Set the number of pulses before it is multiplied by 4.
(G) Control parameters
Description
Set for the operation at
120 Hz or less.
Set for the operation at a
frequency higher than 120
Hz.
Set for the operation at
120 Hz or less.
Set for the operation at a
frequency higher than 120
Hz.
619
PARAMETERS
5
GROUP
G