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Supervised INPUTs
The typical connection for supervised dry contacts is shown in the next figure.
Put the resistors close to the dry contact
Dry contacts
Normally closed
Door
White
yellow
White
yellow
Normally open (Exit)
Push Button
Yellow resistor: 1210 Ohm 1%
White resistor: 392 Ohm 1%
Close contact resistance: 296 Ohm
Open contact resistance: 1210 Ohm
When the cables go out-of-doors is mandatory to use shielded cables. The
cables' shielding must be connected to the ground connector.
For internal wiring without shielded cables it 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
Page 14
input 1+
input 1-
input 2+
input 2-
+12V
Figure 9. Supervised input connection
AWG
mm2
ohm/Km
22
0,35
24
0,2
Table 4. Length of Contact Cables
Ground
[m]
52
240
85
147
INPUTs
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