YASKAWA SVC User Manual page 614

 Absolute Encoders
An absolute encoder outputs the absolute position (position data for the rotational angle) from
a reference position (origin of the encoder).
The absolute encoder uses a battery connected to the battery terminals of the SERVOPACK to
maintain the absolute position data (called the absolute value data) at all times, even when the
power supply is turned OFF. The absolute value data is also updated if the position changes
while the power supply is OFF.
The absolute encoder consists of a detector that is used to detect the absolute position within
one rotation and a counter that is used to count the number of rotations. After automatic oper-
ation starts, the absolute encoder operates in the same way as an incremental encoder.
 Incremental Encoders
Incremental encoders output pulses while the control object is in motion. Position data is not
retained.
 Absolute Value Set Method
This is one of the target position coordinate data setting methods for position control. With this
method, the target position coordinate data is set directly.
Refer to the following section for details.
5.1.4 Position References on page 5-6
 Absolute Value Data
There are two types of absolute value data stored in the absolute encoder: the absolute refer-
ence position (initial incremental pulses, or PO), and the number of rotations from an absolute
reference position (multi-turn data, or N).
The absolute reference position (initial incremental pulses, or PO) is the phase-C position when
the absolute encoder is reset and is the reference position for absolute position detection.
When the absolute encoder is reset, only the number of rotations from the absolute reference
position (N) is cleared. The initial incremental pulses (PO) is not changed.
 Incremental Addition Method
This is one of the target position coordinate data setting methods for position control. When
this method is used, target position coordinate data is set by adding the travel distance to the
previous position reference value.
Refer to the following section for details.
5.1.4 Position References on page 5-6
 Distribution
Distribution is the process in which a slave SERVOPACK outputs a reference from the MP3000
to a Servomotor.
 Pulse Position
The pulse position is the position information managed by the MP3000 converted into pulses.
 Report
"Report" is used for details that are automatically transferred by the system in the CPU without
any action by the user.
 Infinite-length Axis
This is an axis that uses infinite-length position control and resets position data every revolu-
tion.
Refer to the following section for details.
5.1.3 Axis Selection on page 5-5
 Infinite-length Axis Position Control
This control method is used to perform position control without limiting the movement range,
11.6 Terminology
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