Siemens Simatic S7-400 - Manual (Page 533)

Interface Submodules
13-37
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
13.7.2 Connecting Measured Value Sensors to Analog Inputs
Introduction
Depending on the measuring type, you can connect various measured value
sensors to the analog inputs:
• Voltage sensors
• Current sensors as
– two-wire transducers
– four-wire transducers
• Resistance
This section describes how to connect the measured value sensors and what to
look out for when connecting the measured value sensors.
Connecting Measured Value Sensors to Analog Inputs
The maximum permissible voltage difference (V
CM
= 8 V AC) between the inputs
and the internal ground must not be exceeded.
The measuring ranges (current/voltage) are selected via the wiring of the front
connector and by calling the software driver provided for the measuring range.
Unswitched Channels
You must short-circuit unswitched input channels and ground them. This achieves
optimal noise immunity for the analog module.