Yaskawa MP920 User's Manual Design - Manual (Page 482)

11 Maintenance and Inspection
11.3.4 Functions of Battery Module
11-10
1. The Battery Module performs a lithium battery voltage check sequence and outputs the results
when +24 VDC external power supply is turned ON. However, it does not automatically perform
the voltage check while the power is ON unless an external reference is received.
The Battery Module does not externally output an alarm even if the battery voltage drops due to
battery self-discharge and so on while the power is ON. For 24-hour nonstop systems, therefore, it
is recommended that battery voltage check signal CHK be input at regular intervals to check for
lithium battery voltage drop.
Performing a battery voltage check consumes extra battery power. For this reason, it is recom-
mended that a voltage check sequence be performed approximately once a day.
2. To check the lithium battery status while the power is ON, press the battery voltage check switch
on the Battery Module.
Use a tapered precision screwdriver or similar tool to press the battery voltage check switch.
„ Alarm Display/Output Function
The Battery Module externally displays or outputs an alarm when it detects that the lithium
battery voltage drops below the specified level. The table below shows the relationship
between lithium battery status, indicators, and output signals.
Lithium Battery Status, Indicators, and Output Signals
Lithium Battery
Status
Indicator Output Signal Condition
Battery has enough
power. “ALARM1” not lit “ALM1” ON 3.3 V < Battery voltage
“ALARM2” not lit “ALM2” ON
Battery needs to be
replaced. “ALARM1” lit “ALM1” OFF 3.0 V < Battery voltage ≤
3.3 V
“ALARM2” not lit “ALM2” ON
Absolute Encoder
data cannot be guar-
anteed. “ALARM1” lit “ALM1” OFF Battery voltage ≤ 3.0 V
“ALARM2” lit “ALM2” OFF
IMPORTANT