Siemens SIMATIC 500 Series Description And Operating Instructions page 4

3.10 Setting the CPU Dipswitches
Dipswitch Location
and Settings
Enabling Battery
Backup
Installing 505 System Hardware
3-22
Dipswitches are used to set 545/555 CPU operating parameters. The
dipswitches are located near the front of the CPU, behind the bezel or
battery door. See Figure 3-12. To gain access, lower the access door. With the
CPU in its (normal) vertical position, dipswitches pushed to the left are On;
dipswitches pushed to the right are Off.
Figure 3-12 545/555 CPU Dipswitch Location
SW9 is used to set the back-up battery On or Off. As Figure 3-12 indicates,
moving the switch to the left enables the back-up battery; setting the switch
to the right disables the back-up battery.
NOTE: When SW9 is set to the On position, the battery LED indicates the
state of the battery back-up circuit. If the battery LED is illuminated,
memory contents should be maintained; if the LED is not illuminated,
memory contents will not be maintained.
* Port 2 = RS-232/422
Port 1 = Programming port
Dipswitch
Battery On
* For the 545–1103, port 2 is an RS-232 port only.
SIMATIC 545/555/575 System Manual
(On)
1 0 (Off)
Port 2 = RS-485
Port 1 = Printer port
Port 1
Baud rate
Port 2
Baud rate
Battery Off
Not used