Toshiba T2N - Manual (Page 89)

5.Maintenance and Checks
74 PROSEC T2N
Normally the program and 2kwords data register are kept in the built-in
EEPROM of the T2N. On the other hand, other retentive registers’ value and
real time clock’s value can be kept in the RAM with a battery.
A lithium battery is used, which has little self-discharge and can be used over a
wide temperature range. Therefore, during its period of use, and in paticular
when the non-conducting time is long, it can be used with assurance.
The date of istallation of the battery is recorded on the CPU side panel.
Under normal use, it is recommended that the battery should be replaced every
2 years. Check the date of installation and replace using the following
procedure.
There is an LED(BAT) which indicates normal battery voltage on the front of the
CPU module. This is lit when normal. When this LED flashes or is out,
the battery comes into life. Therefore replace the battery within 14days. (It is
recommended that the power supply should not be switched OFF until actual
replacement, in order to protect the program.)
5.4
Battery Replacement
• Remove the CPU module from the basic unit
after turning power OFF.
‚ Loosen the screws of the side panel which
mounts a battery with CPU module.
ƒ Remove the CPU side panel.