Siemens SIMATIC S7-300 Reference Manual page 185

Protection of contacts against overvoltages
You protect the contacts against overvoltages by inserting jumpers (SJ) on the
module between terminals 3 and 4, 7 and 8, 12 and 13 etc. (refer to Figure 3-32).
Terminal assignment and block diagram of the SM 322; DO 8 x Rel. 230 VAC/5A
SF
Channel
number
Status display – green
Figure 3-32 Module View and Block Diagram of the SM 322; DO 8 x Rel. 230 VAC/5A
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
Fault indicator – red
1
1L+
2
3
1L+
4
SJ
5
6
7
1L+
8
SJ
9
10
24V
11
1L+
12
SJ
13
14
15
1L+
16
SJ
17
18
19
20
1M
2L+
1L+
1M 1M
1L+
1M
1M
1L+
1M 1M
1L+
1M
1M
SF
Digital Modules
21
22
23
24
SJ
25
26
27
28
SJ
29
30
24V
31
32
SJ
33
34
35
36
SJ
37
38
39
40
2M
3-101