# Mitsubishi Electric FR-A820-00046 (0.4K) Instruction Manual Page 570

Fr-a800 series.

• Set the encoder orientation gear ratio in Pr.394 Number of machine side gear teeth, Pr.395 Number of motor side gear
teeth An accurate gear ratio (or pulley ratio) from the motor shaft to the spindle is necessary.
Set the correct numbers of gear teeth in Pr.394 and Pr.395.
Pr.394 = A × C × E
Pr.395 = B × D × F
Exercise care so that the A × C × E and B × D × F settings do not exceed 32767. If either or both of them exceed that value, make
approximations.
NOTE
• Pulley ratio: Ratio of vector-driven motor side pulley diameter to spindle side pulley diameter
• Setting example (When the numbers of gear teeth are as follows)
A: 15, C: 43, E: 60, B: 10, D: 28, F: 55
Pr.394 = 15 × 43 × 60 = 38700
Pr.395 = 10 × 28 × 55 = 15400
Since Pr.394setting exceeds 32767 at this time, make approximations as follows.
Pr.394/Pr.395=38700/15400=3870/1540
 Machine end simple orientation control
• Machine end simple orientation control is available when the FR-A8AL option is installed on the inverter and connected to
a machine end encoder. Both machine end orientation control and encoder feedback control/ Vector control is also enabled
at the same time.
• Set the orientation speed at the motor end encoder in Pr.351 Orientation speedOrientation speed.
• Set the rotation direction of the encoder in Pr.359 Encoder rotation direction. If the rotation directions of the motor end
encoder and the machine end encoder differ, set the rotation direction of the motor end encoder.
• To perform encoder feedback control or Vector control using the machine end encoder, set Pr.369 Number of encoder
pulses with the number of motor end encoder pulses converted from the number of machine end encoder pulses.
• To enable encoder feedback control or Vector control and machine end orientation control at the same time using the
machine end encoder, set the number of machine end encoder pulses in Pr.829 Number of machine end encoder
pulses and "0" in Pr.862 Encoder option selection.
Pr.829 setting
9999
Other than 9999 (The
0
number of machine end
encoder pulses (before
1
multiplied by four) is set.)
• When the number of machine end encoder pulses is 4000 and the gear ratio between motor end and machine end is 4:1(4
rotations of motor equals one rotation of machine), set the value as Pr.369 = "1000", Pr.829 = "4000" (the number of
machine end encoder pulses) according to the following formula,
The equivalent of number of motor end encoder pulses = 4000 × 1/4 = 1000
NOTE
• For other settings, refer to descriptions of motor end orientation control in this manual.
Spindle
(A to F indicate the
numbers of gear teeth.)
A
Spindle side
Pr.862 setting
Machine end simple orientation control invalid
Encoder feedback control / Vector control and machine end orientation control at
the same time using the machine end encoder is enabled.
Machine end simple orientation control invalid
A
B
C
D
E
Motor
F
A
B
B
Motor side
Description
5. PARAMETERS
5.14 (A) Application parameters
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