Siemens Simantic ET200SP System Manual page 51

Requirements
Use the following devices to form potential groups with motor starters:
● BaseUnits BU30-MSx
● 3RK1308-0xx00-0CP0 motor starters
Operating principle
Feed in the supply voltage L+ via the BaseUnit BU30-MS1 and BU30-MS3 at the 24V DC
and M terminals.
You can operate the motor starter on a single-phase (L1, N, PE) or a three-phase (L1, L2,
L3, PE) AC voltage system. You connect the required AC voltage directly to the BaseUnits
BU30-MSx (terminals L1, L2(N), L3, PE). You plug the motor starter onto the BaseUnits.
Note
The motor starters' AC power supply is not connected to the AC power supply for the AC I/O
modules (see Chapter "Forming potential groups with AC I/O modules (Page 47)").
Distributed I/O system
System Manual, 12/2016, A5E03576849-AG
Application planning
3.4 Forming potential groups
51