Siemens SIMATIC SM 335 - Connecting the sensor power supply

Connecting the Inputs and Outputs of the SM 335
2-7
SM 335 – High-Speed Analog Input/Output Module for the SIMATIC S7-300
6ES7 335-7HG00-8BA1
2.5 Connecting the sensor power supply
Purpose
The sensor power supply is designed for resistance-type sensors (e. g., linear po-
tentiometers).
Connections
Figure 2-3 shows an example of how to connect the sensor power supply.
Sensor
power
supply
Measuring
signal
ÉÉ
ÉÉ
ÉÉ
ÉÉ
ÉÉ
ÉÉ
10 V
0 V
U
Ref
=10 V
U
SM 335
9M
0+
7 10 V
10 M
0–
8
6 M
ANA
Fig. 2-3 Example of How to Supply the Sensors with Power via the SM 335
Non-isolated configuration
Internally, the SM 335’s analog zero potential (pin 6) is connected with the 10 V
sensor power supply’s zero potential.
If you use the four-wire measuring method shown in Figure 2-3, you must not con-
nect pin 10 to pin 6 or to zero potential. To do so would create a ground loop,
which could cause interference.