Omron CJ1W-MA - REV 10-2008, Operation Manual

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Absolute Encoder Origin Section 8-6
5. Set the absolute encoder type to be used in Operation Switch When Using
Absolute Encoder (Pn002.2 for W Series and Pn00B for G Series).
This step is not required if using the default setting.
6. Setup the absolute encoder.
After setting up the absolute encoder, the power to the Servo Drive must
be turned OFF and then ON again.
7. Start MECHATROLINK communications.
When the connection is established, the absolute value data is read from
the absolute encoder.
8. Set the mechanical origin.
9. Set the origin position offset for the absolute encoder.
After completing this procedure, the mechanical origin will be set whenever
the power is turned ON or MECHATROLINK communications are started.
Establishing the Origin
with an Absolute Encoder The following differences exist in origin searches when using a motor with an
absolute encoder depending on the unit version of the Position Control Unit.
Position Control Units with Unit Version 1.3 or Earlier
Position Control Units with unit version 1.3 or earlier do not support origin
search operations for absolute encoders.
When the origin search operation is executed, the present position is cleared
to 0 or, if the origin search preset function is enabled, it is set to the present
command value after the origin has been established. Any absolute value
data previously read by the Position Control Unit is lost. If the absolute value
data is later read from the absolute encoder, e.g., when the Servo is unlocked
and locked, the coordinate system based on the absolute value data previ-
ously saved in the absolute encoder will be used instead of the origin estab-
lished by the origin search operation.
Position Control Units with Unit Version 2.0 or Later
When the origin search operation is executed, the present position is cleared
to 0 or, if the origin search preset function is enabled, it is set to the present
command value after the origin has been established. If the origin search
operation pattern is set to reversal mode 1, the zero point position offset of the
absolute encoder will be set automatically and saved in the Servo Parame-
ters. The mechanical origin and the zero point position offset in the absolute
encoder can thus be set simultaneously by using a Position Control Units with
unit version 2.0 or later and reversal mode 1 with an absolute encoder.
Refer to 8-6-5 Absolute Encoder's Origin (Zero Point) Position Offset Setting
for details on setting the zero point position offset using an origin search.
Note ORIGIN SEARCH can also be executed when using Servomotors with abso-
lute encoders. By executing ORIGIN SEARCH, however, the present position
will be cleared to 0 when the origin is established. Therefore, the absolute
data read to the PCU in Servo lock status will be lost unless the zero point
position offset is set using the origin search operation for a Position Control
Units with unit version 2.0 or later. The absolute data saved in the absolute
encoder will not be lost and can be obtained by executing SERVO UNLOCK
after the origin search has been completed, and then executing SERVO
LOCK again. The origin position detected, however, will be displaced due to
SERVO UNLOCK execution. Therefore, do not execute ORIGIN SEARCH
when using a Servomotor with absolute encoder unless you set the zero point
position offset using the origin search operation for a Position Control Units
with unit version 2.0 or later.