Siemens SIMATIC ET 200M Operating Instructions Manual page 45

3.5.3 Arrangement of the modules of an ET 200M standard installation
Arrangement rules
The following rules apply to the location of the modules in an ET 200M:
● An ET 200M can only be installed on one mounting rack (rail), because coupling to other
A maximum of 8 (with IM153-2 or IM153-4 PN IO max. 12) signal modules, function modules
or communication processors may be inserted to the right alongside the IM 153-x.
The following figure shows the arrangement of the modules in an ET 200M configuration
equipped with eight S7-300 modules.
①
②
③
Figure 3-7
Greater number of modules with the IM 153-2BAx2 and IM 153-4AA0x
A maximum of 12 modules can be operated with the IM 153-2BAx2 and IM 153-4AA0x
interface module, compared to 8 modules previously.
Restrictions
Use of the high-accuracy time stamp (1 ms accuracy) is only possible with 8 modules. In this
case, a maximum of 8 input modules can be inserted after the IM 153-2BAx2 interface
module in the ET 200M.
Installation in an Intrinsically Safe Area
If you use the ET 200M in intrinsically safe areas, you must insert the dummy module DM
370 between the IM 153-x and the modules in the intrinsically safe area. Only in this way can
you adhere to the necessary thread measure (refer also to the reference manual "S7-300
Automation Systems, ET 200M Ex I/O Modules
(http://support.automation.siemens.com/WW/view/en/1096709)").
ET 200M
Operating Instructions, 12/2008, EWA-4NEB780600602-08
mounting racks via interface modules is not permissible.
1
2
Power supply
IM 153-x
S7-300 modules
Arrangement of the modules of an ET 200M
3.5 Configuring the mechanical structure
3
Assignment planning
43