Siemens S5-135U/155U appendix Terminals, Cabling, Max. Permissible Conductor Cross-Sections

Central Controllers and Expansion Units Power Supply Units

Setting up the Control Input for the Power Supply

Establishing the Cables

The following applies to input EN (Enable Power Supply):

SInput EN monitors the voltage for < 3.6 V; it enables the output voltage at 3.2 V.

SIf two or more units are to be controlled jointly, connect input EN of the PSU in the central controller to the EN inputs of the PSUs in the

expansion unit. Connect the auxiliary voltage UH, for example, to these inputs. In the event of failure of the PSU in the central controller, all units

will then be switched off with the appropriate jumper settings.

Not more than 7 EN inputs may be connected to one UH output (front terminal).

The following applies to selecting the cables for the terminals:

Terminals

Power supply

AC line

DC line

Cabling

Phase	L 1
Neutral	N
Protective cond.	PE
Positive	L +
Chassis 0 V	M
Protective cond.	PE

Max. Permissible Conductor Cross-Sections

4 mm2 solid or 2.5 mm2 flexible

4 mm2 solid or 2.5 mm2 flexible

4 mm2 solid or 2.5 mm2 flexible

4 mm2 solid or 2.5 mm2 flexible

4 mm2 solid or 2.5 mm2 flexible

4 mm2 solid or 2.5 mm2 flexible

Load voltage input (Voltage	24 V input (may be omitted if jumper
monitor, Ext. 24 V DC)	BA-EX is closed)
Enable power supply	Set jumper from EN-UHor apply
	w 3.2 V voltage at EN, with respect
	to output chassis ground

4 mm2 solid or 2.5 mm2 flexible

4 mm2 solid or 2.5 mm2 flexible

Relay terminals, also suitable to 230 V AC / 3 A

Monitor output for 24 V

4 mm2 solid or 2.5 mm2 flexible

4 mm2 solid or 2.5 mm2 flexible

Note

A voltage of more than 50 V must not develop between the output voltages and the protective conductor potential.

System Manual	4-27
C79000-G8576-C199-06