Siemens S7-300 Manual page 3

Terminal connection diagram and block diagram of the
SM 321; DI 16 DC 24 V
SF
V
V
Figure 1 Module view and block diagram of the SM 321; DI 16
Product Information on the Manual S7-300 Module Specifications, Edition 11/2002
A5E00213444-02
s
s
Backplane bus
interface
Channel number
Status display – green
Fault indicator – red
Sensor supplies Vs - green
L+
Wire break
detection
M
L +
Wire break
detection
M
DC 24 V
L+
V
s
V
s
M
24 V
3