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Functions for Servo Drivers Compatible with Absolute Encoders Section 7-7
After a short time has passed to allow the Servo Driver's output to stabilize,
turn ON the High-speed Counter Start Bit (A610.00) from the ladder program.
The encoder's status (multi-turn data), which was acquired when the SEN sig-
nal was turned ON, is received as serial data. After the multi-turn data has
been received through serial communications, the Absolute Number of Rota-
tions Read Completed Flag (A608.05) will go ON. If a reception error occurs
at this point, the Absolute Number of Rotations Read Completed Flag
(A608.05) and Absolute Number of Rotations Read Error Flag (A608.04) will
go ON and the received data will be discarded.
Step 3 (as Needed): Origin
Compensation (Absolute
Offset Preset)
When necessary, the absolute offset preset function can be used to set
encoder's present position as the origin.
Use the absolute offset preset function to store the present value that will
be defined as an origin as the absolute offset; the present value is
computed from the Absolute Number of Rotations PV (A604 and A605)
and the Number of Initial Incremental Pulses (A600 and A601).
To use the absolute offset preset function, turn ON the Absolute Offset Preset
Bit (A610.05).
Note When performing origin compensation, set the absolute offset to 0 before
starting the origin compensation operation. Use the CX-Programmer’s Sys-
tem Setup to set the absolute offset to 0.
To use the absolute offset preset function, wait 30 to 62.5 ms after the Abso-
lute Number of Rotations Read Completed Flag (A608.05) is turned ON and
then toggle (turn ON and then OFF) the Absolute Offset Preset Bit (A610.05).
Note Be sure to perform the absolute offset preset operation before starting normal
Servo Driver pulse outputs. The Absolute Offset Preset Bit’s ON timing
depends on encoder's resolution, etc. Adjust as needed corresponding to the
system.
Step 4 (Required):
Absolute Present Value
Preset
Use the absolute present value preset function to store the absolute
present value in high-speed counter PV 1 (A600 and A601).
To use the absolute present value preset function, toggle (turn ON and then
OFF) the Absolute PV Preset Bit (A610.06).
Step 5 (Required):
Operating Command to
Servo Driver
Turn ON the RUN Signal Output Bit (Servo Lock). Doing so will cause the
Servo Driver to start operating. At the same time, the Motion Control Module
will start receiving pulse trains and counting the number of pulses corre-
sponding to Servo Driver’s rotational displacement.
Step 6 (Required):
Stopping Servo Driver
Turn OFF the RUN Signal Output Bit (Servo Lock). Doing so will stop the
Servo Driver. In addition, turn OFF the Absolute Number of Rotations Read
Bit (A610.07) and High-speed Counter Start Bit (A610.00). When these bits
are OFF, the Motion Control Module will stop counting the pulse trains.