YASKAWA SGMJV User Manual page 285

8.1 System Configuration and Connection Example for SERVOPACK with Fully-closed Loop Control
 Passing First Zero Point in Reverse Direction and Returning after Power ON
When the zero point detection position is first passed in the reverse direction after turning the power supply
OFF and ON again, the encoder dividing phase-C pulse (CN1-21, CN1-22) is not output.
However, after the zero point detection position is passed in the forward direction and the encoder dividing
phase-C pulse is output, the encoder dividing phase-C pulse is output even when the zero point detection posi-
tion is passed in the reverse direction.
Scale count-up
direction
Zero point
detection position
Power ON
Phase-C pulse
output
The phase-C pulse is not
output when passing the
detection position in reverse
direction first.
 External Encoder with Multiple Zero Points and Passing First Zero Point in Forward
Direction and Returning after Power ON
When you use an external encoder with multiple zero points, each zero point operates in the same manner as

described in 9.1.6 Passing First Zero Point in Forward Direction and Returning after Power ON.
Scale count-up
direction
Zero point 1
detection position
Zero point 2
detection position
Power ON
Phase-C pulse
output
Zero point 1
The phase-C pulse is also output when passing this
point in reverse, because the SERVOPACK has
recorded the position where the phase-C pulse was
originally output when first passing the position in the
forward direction.
The phase-C pulse is also output when passing this point in reverse,
because the SERVOPACK has recorded the position where the
phase-C pulse was originally output when first passing the position in
the forward direction.
Zero point 1 Zero point 2
Even after zero point 1 has first been
passed in the forward direction, the
phase-C pulse is not output here
because zero point 2 is passed in
reverse direction.
Time
Time
Zero point 2
8
8-9