4-10
SIMATIC PC RI25/45, Technical Description
C79000-G7076-C808-01
4.6
Battery-Backed RAM (optional)
The maximum capacity of the battery-backed RAM is limited to 64 Kbytes
because the PC’s memory area for ADD-ON components is very limited and
the addressing of the RAM should be located in the memory-mapped area.
The address area listed below applies to the programmer. The motherboard
mirrors the address areas FFF8:0000h to FFFF:FFFFh on to the 16th Mbyte
of the AT bus; that is, on the addresses 00F8:0000h to 00FF:FFFFh.
The base address is set via address switch S1 (on = switch closed).
Address switch
S1
RAM address area
on
000D:0000 to 000D:FFFF (standard setting)
off
00FD:0000 to 00FD:FFFF
A lithium battery provides the RAM backup power.
Battery: lithium battery 3.6V type SL-750 manufacturer: Fa. Sonnenschein
Lithium GmbH
Size
Addressing
Address Settings
Backup
Monitoring Module