Yaskawa MP940 Reference Manual - Manual (Page 297)

MotionSuite™ MP940 Machine Controller Reference Manual Outline of Absolute Encoder Functions
7-3
Battery
When using an absolute encoder, a battery is needed to record position data
to the MP940 unit and the SGDH.
The following table shows the conditions under which a battery is needed.
Initialization of Absolute Data
At power ON, the absolute data is sent to the servo amplifier as well as the
MP940 module, the absolute position is calculated, and the machine
coordinates are automatically set. In this way, the absolute machine position
can be detected immediately after power ON, and automatic run immediately
performed.
SGDH MP940 Usage Method
No No Flash Operation
Incremental Encoder Use
Using absolute data as incremental data.
No Yes No Flash Operation
Incremental Encoder Use
Using absolute data as incremental data.
Yes Yes No Flash Operation
Absolute Encoder Use
SGDH
Servo Amplifier
MP940
Module
Battery for Absolute
Encoder Position Data
Memory
Battery for RAM
Backup & Absolute
Position Data Memory