INPUTs
Page 13
Digital INPUTs
The typical connection for digital dry contacts is shown in the next figure.
input 1+
input 1-
input 2+
input 2-
Normally closed (door)
Push Button
+12V Ground
Dry contact
Normally open (Exit)
Figure 8. Clean Contacts Connection Example
When the cables go out-of-doors it is mandatory to use shielded cables. The
cables’ shielding must be connected to the ground connector.
For internal wiring without shielded cables is recommended an electrical
environment where the cables are well separated, even at short runs,
especially to the power cables or external cables which can be essentially
subjected to interference or lighting.
Use a twisted-pair cable for the contact cables. Make sure that the cables
correspond in size to the norms indicated in.
Max resistance = 25 Ohm
AWG
mm2
ohm/Km
[m]
22
0,35
52
240
24
0,2
85
147
Table 3. Length of Contact Cables
