# Mitsubishi Electric FR-A820-00046 Instruction Manual Page 703

Parameters
Encoder orientation gear ratio setting (Pr. 394, Pr. 395) (Vector control)
Set the encoder orientation gear ratio for machine end orientation control.
Set the encoder orientation gear ratio in Pr. 394 "Number of machine side gear teeth" and in 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 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 ×If either or both of them exceed that value, make ap-
proximations.
(A to F indicate the
numbers of gear teeth.)
NOTE
The pulley ratio is the ratio of vector-driven motor side pulley diameter to spindle side pulley
diameter.
Example
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. 394 setting exceeds 32767 at this time, make approximations as follows:
Pr. 394
Pr. 395
FR-A800
Spindle
A
B
C
D
E
F
Spindle side
38700
3870
=
=
15400
1540
Fig. 5-254:
Gear ratio
Motor
A
B
Motor side
(A) Application parameters
A
B
I002873E
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