Download CPU Specifications and Operations

3--6
CPU Specifications and Operation
Using Battery Backup
An optional lithium battery is available to maintain the system RAM retentive
memory when the DL305 system is without external power. Typical CPU battery life
is five years, which includes PLC runtime and normal shutdown periods. However,
consider installing a fresh battery if your battery has not been changed recently and
the system will be shutdown for a period of more than ten days.
NOTE: Before installing or replacing your CPU battery, back-up your V-memory and
system parameters. You can do this by using DirectSOFT to save the program,
V-memory, and system parameters to hard/floppy disk on a personal computer.
CPU Specifications
and Operation
To install the D2--BAT--1 CPU battery in the
DL350 CPU:
1. Press the retaining clip on the battery door
down and swing the battery door open.
2. Place the battery into the coin--type slot.
3. Close the battery door making sure that it
locks securely in place.
4. Make a note of the date the battery was
installed.
DL350
WARNING: Do not attempt to recharge the battery or dispose of an old battery
by fire. The battery may explode or release hazardous materials.
Enabling the
Battery Backup
The battery can be enabled by setting bit 12 in V7633 (B7633.12) ON (see example
below). In this mode the battery Low LED will come on when the battery voltage is
less than 2.5VDC (SP43) and error E41 will occur. In this mode the CPU will maintain
the data in C,S,T,CT, and V--memory when power is removed from the CPU,
provided the battery is good. The use of a battery can also determine which
operating mode is entered when the system power is connected. See CPU Setup,
which is discussed later in this chapter.
If you have installed a battery, the battery circuit can be disabled by turning OFF
B7633.12. However, if you have a battery installed and select “No Battery”
operation, the battery LED will not turn on if the battery voltage is low.
SP0
LD
K1000
OUT
B7633.12
SP43
SP4
Y0
OUT
Battery Low Lamp
DL350 User Manual, 2nd Edition
This rung enables the
battery operation.
This rung will flash Y0 if
the battery gets low.