
B–64115EN/01
2. HARDWARE
195
Part programs, offset data, and system parameters are stored in CMOS
memory in the control unit. The power to the CMOS memory is backed
up by a lithium battery mounted on the front panel of the control unit. The
above data is not lost even when the main battery goes dead. The backup
battery is mounted on the control unit at shipping. This battery can
maintain the contents of memory for about a year.
When the voltage of the battery becomes low, alarm message “BAT”
blinks on the display and the battery alarm signal is output to the PMC.
When this alarm is displayed, replace the battery as soon as possible. In
general, the battery can be replaced within two or three weeks, however,
this depends on the system configuration.
If the voltage of the battery becomes any lower, memory can no longer
be backed up. Turning on the power to the control unit in this state causes
system alarm 910 (SRAM parity alarm) or 935 (SRAM ECC error) to
occur because the contents of memory are lost. Clear the entire memory
and reenter data after replacing the battery.
The following two kinds of batteries can be used.
D Lithium battery built into the CNC control unit.
D Two alkaline dry cells (size D) in the external battery case.
NOTE
A lithium battery is installed as standard at the factory.
When a lithium battery is used
Prepare a new lithium battery (ordering code: A02B–0200–K102
(FANUC specification: A98L–0031–0012)).
1) Turn on the power to the CNC. After about 30 seconds, turn off the
power.
2) Remove the old battery from the top of the CNC control unit.
First, unplug the battery connector, then take the battery out of its
case.
The battery case of a control unit without option slots is located at the
top end of the unit as shown in the figure of the previous page. The
battery case of a control unit with 2 slots or 4 slots is located in the
central area of the top of the unit (between fans).
3) Insert a new battery and reconnect the connector.
2.10
REPLACING
BATTERY
D Replacement procedure