YASKAWA SGD7S-1R9D, Product Manual

Page: 204 / 603

6.8 Absolute Encoders
6.8.2 Structure of the Position Data of the Absolute Encoder
6-32
6.8.2 Structure of the Position Data of the Absolute Encoder
The position data of the absolute encoder is the position coordinate from the origin of the absolute
encoder.
The position data from the absolute encoder contains the following two items.
•
The number of rotations from the origin of the encoder coordinate system (called the multiturn data)
•
The position (number of pulses) within one rotation
The position data of the absolute encoder is as follows:
Position data of absolute encoder = Multiturn data
×
Number of pulses within one encoder rotation
(setting of Pn212) + Position (number of pulses) within one rotation.
For a single-turn absolute encoder, the multiturn data is 0.
6.8.3 Output Ports for the Position Data from the Absolute
Encoder
You can read the position data of the absolute encoder from the PAO, PBO, and PCO (Encoder
Divided Pulse Output) signals.
The output method and timing for the position data of the absolute encoder are different in each case.
A conceptual diagram of the connections of the PAO, PBO, and PCO (Encoder Divided Pulse Output)
signals to the host controller is provided below.
The PAO (Encoder Divided Pulse Output) signal outputs the position data from the absolute encoder
after the control power supply is turned ON.
The position data of the absolute encoder is the current stop position. The absolute encoder outputs
the multiturn data with the specified protocol. The absolute encoder outputs the position within one
rotation as a pulse train. It then outputs pulses as an incremental encoder (incremental operation sta-
tus).
The host controller must have a reception circuit (e.g., UART) for the position data from the absolute
encoder. The pulse counter at the host controller will not count pulses when the multiturn data (com-
munications message) is input because only phase A is input. Counting starts from the position of the
absolute encoder within one rotation.
The output circuits for the PAO, PBO, and PCO signals use line drivers. Refer to the following section
for details on line drivers.
4.5.4
I/O Circuits
on page 4-33
Signal Status
Signal Contents
When Using an Absolute Encoder
PAO
First signal Multiturn data position within one rotation (pulse train)
During normal operation Incremental pulses
PBO
First signal Position within one rotation (pulse train)
During normal operation Incremental pulses
PCO Always Origin pulse
Serial
data
ENC
CN1
Host controller SERVOPACK
PAO
PBO
PCO
CN2
Conversion of
serial data to
pulses
Dividing
circuit
(Pn212)