Specifications

Using a terminal block
to hold the diodes
makes the wiring neater.
For example, the following circuit allows switches to select files 3 and 5:
File 3
File 5
Ground
VoltageContacts
SWITCH
1 2
I/O CONNECTOR
CONNECTOR DB37
19
37
18
36
17
35
16
34
15
33
14
32
13
31
12
30
11
29
10
28
9
27
8
26
7
25
6
24
5
23
4
22
3
21
2
20
1
1N4148
2 1
1N4148
2 1
SWITCH
1 2
1N4148
2 1
1N4148
2 1
Voltage inputs, such as from a PLC, could be wired this way:
24 Volt Output 8
Ground Reference
24 Volt Output 4
24 Volt Output 2
24 Volt Output 1
PLC
VoltageContacts
I/O CONNECTOR
CONNECTOR DB37
19
37
18
36
17
35
16
34
15
33
14
32
13
31
12
30
11
29
10
28
9
27
8
26
7
25
6
24
5
23
4
22
3
21
2
20
1
Diodes are not needed, since the PLC can actuate any combination of lines desired.