Mitsubishi Electric MELSERVO-J3 Series Handbook page 417

Part 6: Common Reference Material
(a) Parameter setting method
1) Select an encoder pulse count polarity.
This parameter is used to set the load-side encoder polarity to be connected to CN2L connector
in order to match the CCW direction of servo motor and the increasing direction of load-side
encoder feedback. Set this as necessary.
2) A/B/Z-phase input interface encoder Z-phase connection judgement function (It is not available
with MR-J4W2-_B servo amplifiers.)
This function can trigger an alarm by detecting non-signal for Z phase.
The Z-phase connection judgement function is enabled by default. To disable the Z-phase
connection judgement function, set [Pr. PC27].
(b) How to confirm the scale measurement encoder feedback direction
You can confirm the directions of the cumulative feedback pulses of servo motor encoder and the
load-side cumulative feedback pulses are matched by moving the device (scale measurement
encoder) manually in the servo-off status. If mismatched, reverse the polarity.
(3) Confirmation of scale measurement encoder position data
Check the scale measurement encoder mounting and parameter settings for any problems.
Operate the device (scale measurement encoder) to check the data of the scale measurement encoder
is renewed correctly. If the data is not renewed correctly, check the wiring and parameter settings.
Change the scale polarity as necessary.
[Pr. PC27]
0 0 0
Encoder pulse count polarity selection
0: Load-side encoder pulse increasing direction in the servo motor CCW
1: Load-side encoder pulse decreasing direction in the servo motor CCW
Servo motor
Linear encoder
[Pr. PC27]
0 0 0
Selection of A/B/Z-phase input interface encoder Z-phase connection judgment function
0: Enabled
1: Disabled
6 - 140
Servo motor CCW direction
Address increasing direction of linear encoder