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Pelco Manual C690M-E (11/04) 23
Figure 8b. Unsupervised Alarm Operation
UNSUPERVISED, NORMALLY CLOSED
TIME
+5V
+5V
0.1uF
0.1uF
INPUT
VOLTAGE
STAND-BY MODE
2.5V
0V
POINT A
POINT A
10K
10K
100K
GND
GND
GND
EQUIPMENT SIDE
ALARM WIRING SIDE
NORMAL
CURRENT FL0W
NO ALARM
S
Processor
CIRCUITRY
GND
TTL-CMOS
EXTERNAL
CONTROL
<
_
50ms
PIN 1
PIN 2
ALARM
ALARM
IN THIS CONFIGURATION, TRANSISTOR "S" (THE SWITCH) IS BIASED
FOR CONDUCTION AND POINT "A" RESIDES CLOSE TO 0V. IF THE
TRANSISTOR IS BIASED TO THE OFF STATE OR IF THE LINE IS CUT TO
STOP CURRENT FLOW, POINT "A" RISES TOWARD 5V AND AN ALARM
CONDITION.
NOTE: PIN NUMBERS
REFER TO TYPICAL
HEADER ALARM INPUT
NUMBERS ON MATING
PLUGS
NOTE: TIME DURATION
OF THE INPUT
CONTROL SIGNAL MUST
BE 50ms OR MORE
HIGH = STAND-BY MODE
LOW = ALARM
UNSUPERVISED, NORMALLY OPEN
TIME
+5V
+5V
0.1uF
0.1uF
INPUT
VOLTAGE
STAND-BY MODE
2.5V
0V
POINT A
POINT A
10K
10K
100K
GND
GND
GND
EQUIPMENT SIDE
ALARM WIRING SIDE
NORMAL
CURRENT FL0W
NO ALARM
S
Processor
CIRCUITRY
GND
TTL-CMOS
EXTERNAL
CONTROL
<
_
50ms
PIN 1
PIN 2
ALARM
ALARM
IN THIS CONFIGURATION, TRANSISTOR "S" (THE SWITCH) IS BIASED
FOR NON- CONDUCTION AND POINT "A" RESIDES CLOSE TO 5V. IF AN
INPUT CONTROL SIGNAL OF SUFFICIENT DURATION TURNS ON THE
TRANSISTOR FOR ALARM ACTIVATION OR IF THE LINE IS SHORTED,
POINT "A" WILL FALL TOWARD 0V AND AN ALARM CONDITION.
NOTE: PIN NUMBERS
REFER TO TYPICAL
HEADER ALARM INPUT
NUMBERS ON MATING
PLUGS
NOTE: TIME DURATION
OF THE INPUT
CONTROL SIGNAL MUST
BE 50ms OR MORE
HIGH = ALARM
LOW = STAND-BY MODE