Continuum I/O System Reference
119
Connecting Inputs
All AC-1 and AC-1-ABA inputs are supervisory inputs. The following drawings depict the
six types of supervisory inputs that exist—three normally closed and three normally open
types. After the drawings, there is an explanation of which types are recommended for
access control installations.
The AUX input
The module supports the use of a second reader LED. The first is connected to the
standard LED output connection and the
optional
second is connected to the Input 1
(AUX) connection. Using this second LED eliminates one supervised input.
Normally Closed Supervisory Inputs
NC Series
With this type of input wiring, a resistor is placed in series with the input. When the door
switch is closed (normal position) the door is assumed to be closed. The circuit presents
a reading of 10K ohms at the input.
Circuit Action Input Senses Condition
Switch Closed External Resistance Door Closed
Switch Opened Infinite Resistance Door Open
Wire Cut Infinite Resistance Door Open ‘Violation’
Input Shorted Zero Ohms Violation or error
When the door is opened the switch opens and an infinite resistance is measured. If the
wires to the door are cut it also appears as a “door open” condition. In this case there
would be a door open without a valid card swipe or valid keypad entry resulting in a “door
violation”. Shorting the input causes a zero ohm resistance which also should result in a
door violation.
AC-1
AUX
or
DOOR
or
REX
RET
Contact
Closure
External
Resistor
10 K
Ω
typical
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