Siemens S7-400 Benutzerhandbuch

13-38

S7-400, M7-400 Programmable Controllers Module Specifications

A5E00069467-07

Potential differences can occur between the individual measured value sensors in
the case of isolated measured value sensors. These potential differences can
occur as the result of interference or the physical distribution of the measured value
sensors.

Ensure that the V

CM

 (common mode voltage) does not exceed the permissible

value. Violation of the permissible value can result in wrong measured values.

Figure 13-13 shows the connection of isolated measured value sensors.

+

-

V

E0

Isolated measured
value sensors

Ground bus

MV

0+

M

0-

+

-

V

E1

MV

1+

M

1-

+

-

V

CM0

+

-

V

CM1

M

SENSOR

Figure 13-13 Connection of Isolated Measured Value Sensors