Yaskawa MP920 User's Manual Design - Manual (Page 481)

11.3 Absolute Encoder Battery
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11.3.4 Functions of Battery Module
This section describes the functions of the Battery Module.
„ Data Backup for Absolute Encoder
The Battery Module backs up motor revolution data from the Absolute Encoder by using a
high-capacity capacitor and lithium battery.
When the power supply to the MP920 is turned OFF, the Battery Module first uses the built-
in high-capacity capacitor to back up the motor revolution data from the Absolute Encoder.
Next, when the voltage of the capacitor drops below that of the lithium battery, the Battery
Module uses the lithium battery to back up the motor revolution data from the Absolute
Encoder
The Battery Module does not back up the ladder logic programs, motion programs, parameters, and
other data stored in the memory of the MP920.
„ Data Backup for Absolute Encoders for up to Eight Axes
The Battery Module can be connected to the BAT terminal of the SVA-01A Module to back
up motor revolution data from Absolute Encoders for up to eight axes.
When Absolute Encoders are used for all four axes for SVA-01A Modules, the Battery Mod-
ule can be connected to two SVA-01A Modules.
„ Backup Time
When Absolute Encoders are connected to eight axes, the Battery Module can back up data
from these Absolute Encoders for one year even if they receive absolutely no power supply.
However, if the Absolute Encoder rotates while it receives no power supply, the backup time
will be shortened because the Absolute Encoder consumes much electrical power.
„ Lithium Battery Voltage Check Function
The Battery Module checks the voltage of the built-in lithium battery and externally outputs
the results by means of an indicator and output signal.
A lithium battery voltage check is performed in the following situations.
• When the Battery Module is turned ON
• When the battery voltage check switch on the Battery Module is pressed
• When battery voltage check signal CHK is input
IMPORTANT