Siemens S7-300 - Page 4

4
Product Information on the Manual S7-300 Module Specifications, Edition 11/2002
A5E00213444-02
Terminal assignment diagram for the redundant supply of sensors
The figure below shows how sensors can additionally be supplied by means of Vs
with a redundant voltage source – for example, via another module.
Vs
M
L+
1 L+
2 L+
to the sensors
±
Digital input
module
Short-circuit-
proof driver
Figure 2 Terminal assignment diagram for the redundant supply of sensors of the SM
321; DI 16 DC 24 V
Terminal assignment diagram of the resistor wiring of the sensors
To detect a wire break, it is necessary to wire sensor contacts with a resistor.
L +/ V
s E x.x
15 k
W
... 18 k
W
Figure 3 Terminal assignment diagram of the resistor wiring of the sensors of the SM
321; DI 16 DC 24 V