Siemens S5-135U/155U System Manual page 492

Analog Input/Output Modules
If, with voltage outputs, an excessively great voltage drop must be expected
on the lines to the load, you must route the sensor lines S+(x) and S-(x) to the
load.
When voltage outputs are not used, the S+(x) sensor lines in the front
connector must be connected to the corresponding voltage output terminals
(QV(x)) with wire jumpers. The S-(x) sensor lines must be connected to
M
You must also insert the same jumpers if only current outputs are used.
Unused current outputs may remain open.
The maximum load for the current outputs including line resistance, must not
exceed 300 ohms.
Connecting Loads
The voltage outputs of the 470 analog output module are wired as follows:
to Voltage Outputs
QV0
S+0
+
–
S–0
M
ANA
Figure 9-41 Connecting Loads
Four-Wire Circuit
The S+(x) and S-(x) sensor lines must be routed to the load (four-wire
circuit) if the voltage drop on the lines to the load is not negligible. The
common connection for the voltage outputs is M
lines to the load is negligible, you can connect S+(x) to QV(x) and S-(x) to
M
When voltage outputs are unused, you must insert jumpers in the front
connector, e.g. QV(3) to S+(3) and S-(3) to M
3 (see previous section).
9-110
with wire jumpers.
ANA
QV1 QV2
S+1
S+2
+
–
S–1
S–2
in the front connector.
ANA
QV3
Jumper
S+3
+
–
S–3
Jumper
M
ANA
No Load at QV3
. If the voltage drop on
ANA
for unused voltage output
ANA
System Manual
C79000-G8576-C199-06