Siemens SIMATIC ET 200SP System Manual page 52

Placement and grouping of I/O modules and motor starters
For the potential group (L+/M), the following slot rules apply within the motor starter modules
and other I/O modules of the ET 200SP:
● An unassembled BaseUnit (BaseUnit with BU cover) must be inserted between the CPU,
an interface module or an I/O module and the motor starter. This is not necessary
between the motor starters.
● The empty slot can take on the potential (24 V DC) of the potential group on the left of it
(L+, M), i.e. I/O modules and motor starters can be operated in the same potential group.
● If you would like to insert an I/O module on the right of a motor starter, then use only one
BaseUnit of the BU...D Typ A0 type (light terminal box).
● The BaseUnits BU30-MS2, BU30-MS4, BU30-MS5, BU30-MS6, BU30-MS7, BU30-MS8,
BU30-MS9 and BU30-MS10 can continue the potential group of other BaseUnit types.
However, note the following exceptions:
– Only a BaseUnit of type BU30-MS1 or BU30-MS3 may follow an AS-i module
– Only BaseUnits with fail-safe motor starters can be connected together in the same
Hazardous Voltage
Can Cause Death, Serious Injury, or Property Damage.
Hazardous electrical voltage can cause electric shock, burns and property damage.
Disconnect your system and devices from the power supply before starting any assembly
tasks.
Distributed I/O system
System Manual, 09/2019, A5E03576849-AJ
(AS-i potential group).
potential group of an F-PM-E.
WARNING
Application planning
4.5 Forming potential groups
51