Forming Potential Groups With Ac I/O Modules - Siemens SIMATIC ET 200SP System Manual

3.3.2

Forming potential groups with AC I/O modules

Introduction
The AC I/O modules of the ET 200SP are required to connect sensors/actuators with
alternating voltage 24 to 230 V AC.
Requirements
BaseUnits BU20-P12+A0+4B (BU type B1) and
● DI 4x120..230VAC ST digital input module
● DQ 4x24..230VAC/2A ST digital output module
Operating principle
Connect the required alternating voltage for the AC I/O modules directly at the BaseUnits
BU20-P12+A0+4B (terminals 1L, 2L/1N, 2N). Insert the AC I/O modules on the BaseUnits.
Note
Placing the BaseUnits for AC I/O modules
If you insert an AC I/O module as the first I/O module, a BaseUnit BU20-P12+A0+4B can be
the first BaseUnit to the right of the CPU/interface module in the ET 200SP configuration.
The requirement is that you use a CPU as of V3.0 or IM 155-6 (as of V3.0).
• The BaseUnits BU20-P12+A0+4B do not monitor the connected alternating voltage.
Please note the information on limiting the overvoltage and power rating in the AC I/O
module manuals.
• Remember to take the BaseUnit type into account during configuration.
①
②
③
④
⑤
⑥
Figure 3-4
Distributed I/O system
System Manual, 12/2015, A5E03576849-AF
CPU/interface module
24 V DC potential group
BaseUnits with DC I/O modules
BaseUnits BU 20-P12+A0+4B with AC I/O modules
Direct voltage
Alternating voltage
Placing the BaseUnits for the AC I/O modules
Application planning
3.3 Forming potential groups
35