Omron CJ1W-NC271 - 12-2009, Operation Manual

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Absolute Encoder Origin
Section 8-6
8-6 Absolute Encoder Origin
8-6-1 Absolute Encoder Overview
The absolute encoder's battery backup enables absolute value data to be
held even if the power to the CPU Unit (PCU) or Servo Drive is turned OFF.
Therefore, after turning ON the power to the CPU Unit (PCU), the saved abso-
lute value data can be read, enabling positioning at the present position that
existed before the power was turned OFF.
The Servo Parameter Absolute Origin Offset for G-series Servo Drives
(Pn200) or Absolute Encoder Zero Point Position Offset for G5-series/W-
series Servo Drives (Pn808) for absolute value data that is read can be used
to offset the mechanical origin.
When an absolute encoder is used to determine the origin, it is not necessary
to perform origin searches every time the power is turned ON, as is required
for devices such as incremental encoders.
Limit input in
opposite direction
from origin search
direction
Time
1
0
1
0
1
0 The origin search operation
settings determine the motor
operation and phase Z signal
detection operation when the
origin proximity input signal
turns ON or OFF.
Motor rotation
Origin proximity
input signal
Phase Z signal
Provide a margin in the phase Z signal of at least two
MECHATROLINK communications cycles plus 4 ms.
Note: