Siemens SIMATIC S5 Manual page 150

Address space By default, the IM 308-C uses the address space (F)F800
used addressing the distributed I/O. This address space is also required if you use
only linear or page addressing.
Caution
!
Danger of double addressing
The IM 308-C uses fully one or more of the address areas shown in Table
9-1 under DP window (default: (F)F800
No part of these address areas may be used by other modules such as CPs,
IPs in the CP area, central I/O in the IM3/IM4 area or the WF 470 position-
sensing module in the central programmable controller.
ET 200 Distributed I/O System
EWA 4NEB 780 6000-02a
IM 308-C – addressing, diagnostics and use of the FB IM308C
to (F)F9FF
H
to (F)F9FF ).
H H
for
H
9
9-3