M7-400 Expansions
12-7
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
12.2.1 Addressing the EXM 478 Expansion Module
Introduction
In order to be able to program the interface submodules in the EXM 478 expansion
module, you must be able to determine their addresses. There are the following
addressing methods:
•Addressing in the AT-compatible I/O address area
•Addressing in the M7-400-specific I/O address area
In this section, you will find information on both methods of addressing the interface
submodules.
Addressing in the AT-Compatible I/O Address Area
Some of the interface submodules are automatically configured by the BIOS for
operation in the AT-compatible I/O address area. This automatic configuration
takes place, for example, for:
•The IF 962-VGA interface submodule
•Up to 4 COM ports (COM1 to COM4)
•Up to 3 LPT ports (one LPT port on the MSM 478 and two interface submodules
IF 962-LPT)
Further interfaces are configured in the BIOS setup. See the CPU/FM description
to learn how to operate the BIOS setup. The description of the interface
submodules will show the specific settings possible.
To configure in the BIOS setup, you must know the submodule receptacle numbers
of the interface submodule receptacles (slots). You will find this information in
Figure 12-4 later in this section.

Addressing in the M7-400-Specific I/O Address Area

All interface submodules can be accessed via M7-400-specific I/O addresses.
There is a description of how to determine the I/O address of an interface
submodule in the “specific address area” starting from page 12-10.
You require this information to program an interface submodule that is not
addressed in the AT-compatible address area.