The load can also be switched via a contact – Siemens S5-135U/155U User Manual
Page 335
8-23
System Manual
C79000-G8576-C199-06
The load can also be switched via a contact.
Output 1
Output 2
ELR
Phase (L)
Load
Neutral (N)
ELR = Electronic Load Relay
ELR
Manual
Figure 8-11
Parallel Connection of Outputs for AC Voltage Outputs
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.
Reference Potential
+
+
DQ
e.g. 441
0 V
+
+
DQ
e.g. 441
0 V
0 V
e.g. 420
DI
0 V
e.g. 420
DI
2L+
1L+
I I
I I
I I I
I I
AC
230V
DC
24V
+
_
+
_
AC
230V
DC
24V
L
_
Q
L
Q L
Q
Q
Q
Q
L
Q
Q
L
Central Ground Point
or Rack or the CC/EU
and Connection
to Protective
Conductor (PE)
Figure 8-12
Feeding of Non-Floating Input/Output Modules from Two Power Supply Units
Connection of
Input/Output
Modules to Two
Power Supply Units
Digital Input/Output Modules