Yaskawa MP940 Reference Manual - Manual (Page 296)

Outline of Absolute Encoder Functions MotionSuite™ MP940 Machine Controller Reference Manual
7-2
Absolute Encoder Basics
Absolute Encoder
Absolute value detection is executed in a semi-closed loop by using an
absolute encoder mounted on the motor. The device consists of the encoder
itself, which detects the absolute position within one turn, and a counter,
which counts the number of turns.
Absolute Data
The absolute data recorded by the absolute encoder consists of the “No. of
Turns From Absolute Base Position (P)” and the “Position Within Single
Motor Turn (PO)”. This absolute data is read as serial data upon powering on
the device. The device operates thereafter in the same manner as an
incremental encoder.
That means, assuming
The absolute value (P) is derived by:
Absolute Data Storage
The absolute encoder uses a battery to save the absolute data at power cutoff.
Changes are also updated.
Number of rotations from absolute standard position : N
Number of Pulses per motor rotation : RP
Position within motor rotation : PO
Absolute Position (P) = N x RP + PO