Siemens S7-400 Supplying Power to Modules, Power Supply Modules and Load Current Power Supplies

Wiring the S7-400

4.1Supplying Power to Modules

Power Supply Modules and Load Current Power Supplies

The modules of the S7-400 system are supplied with all the required operating voltages by a power supply module, via the backplane bus of the rack. Which power supply module you use in a rack depends on your system requirements (line voltage, current consumption of the modules used).

You must provide load voltages and currents via external load current power supplies.

The following figure shows how the individual modules of the S7-400 are supplied with current and voltage.

S7-400

power supply module

Line voltage:

120/230 VAC with supply isolator

or 24 VDC

Operating voltages 5 VDC and 24 VDC via backplane bus

S7-400

modules (DC or AC)

Load current via front connector

Load current power supply

Note

The power supply modules must not be connected in parallel on their secondary sides.

4-2	Automation System S7-400	Hardware and Installation
		A5E00850741-01