Siemens S5-135U/155U appendix Load can also be switched via a contact

Digital Input/Output Modules

The load can also be switched via a contact.

ELR

Output 1

Manual ELR

Output 2

Phase (L)

ELR = Electronic Load Relay

Load

Neutral (N)

Figure 8-11 Parallel Connection of Outputs for AC Voltage Outputs

Connection of

Input/Output Modules to Two Power Supply Units

Given here are two examples of the feeding of inputs and outputs of different modules from two power supply units.

With non-floating input/output modules, the negative terminals (L-) of the power supply units are connected to reference potential (PE) because the inputs of the 420 module are referred to chassis ground.

Central Ground Point

or Rack or the CC/EU

Reference Potential

DI

0 V

DI

0 V

DQ

0 V

DQ

0 V

e.g. 420

e.g. 420

e.g. 441

e.g. 441

I I

I I

I I I

I I

L Q Q Q L

Q Q

L

Q

L Q

Q

and Connection

+

+

+

+

to Protective

Conductor (PE)

2L+

1L+

AC

+

AC

+

230V

230V

_

DC

_

DC

L _

24V

24V

Figure 8-12 Feeding of Non-Floating Input/Output Modules from Two Power Supply Units

System Manual	8-23
C79000-G8576-C199-06