Siemens S5-135U/155U appendix Connecting Loads

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 MANA with wire jumpers.

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	QV1	QV2
S+0	S+1	S+2
+		+
±	S±1	±
S±0		S±2

MANA

+

±

QV3

S+3

S±3

MANA

Jumper

Jumper

No Load at QV3

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 MANA. If the voltage drop on lines to the load is negligible, you can connect S+(x) to QV(x) and S-(x) to MANA in the front connector.

When voltage outputs are unused, you must insert jumpers in the front connector, e.g. QV(3) to S+(3) and S-(3) to MANA for unused voltage output 3 (see previous section).

9-110	System Manual
	C79000-G8576-C199-06