Pelco C690M-E operation manual Alarm

SUPERVISED, NORMALLY CLOSED

IN THIS CONFIGURATION, TRANSISTOR "S" (THE SWITCH) IS BIASED FOR CONDUCTION AND WIRED IN SERIES WITH ITS 10K COLLECTOR RESISTOR. ALONG WITH THE INTERNAL 10K RESISTOR ON THE EQUIPMENT SIDE, THEY FORM A VOLTAGE DIVIDER NETWORK THAT LEAVES POINT "A" AT ABOUT 2.5V (WHICH IS MID-POINT IN THE "STAND-BY MODE" VOLTAGE RANGE SHOWN IN THE ALARM DIAGRAM). A HIGH CONTROL SIGNAL (TTL) GREATER THAN 50ms DURATION ACTIVATES NORMAL STAND-BY MODE.

ANYTHING THAT MAKES THE TRANSISTOR TURN OFF (EFFECTIVELY AN OPEN) OR CAUSES A LOW CONTROL SIGNAL RESULTS IN AN ALARM CONDITION AS POINT "A" GOES FROM 2.5V TOWARD 5V. SIMILARLY, A SHORTED CONDITION MAKES THE VIDEO DROP 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

		VOLTAGE
		DIVIDER
	_<	NETWORK
	50ms
HIGH = STAND-BY MODE
LOW = ALARM		S
TTL-CMOS
EXTERNAL		10K
CONTROL

GND

	INPUT
+5V	VOLTAGE
	A L A R M
3.3V
POINT A
1.65V	STAND-BY MODE
	A L A R M
0V
	TIME
ALARM	EQUIPMENT SIDE
WIRING SIDE	+5V

POINT A
	10K
PIN 1		100K	Processor
			CIRCUITRY
10K	0.1uF
PIN 2		0.1uF
	GND	GND

NORMAL

CURRENT FL0W

NO ALARM

GND

SUPERVISED, NORMALLY OPEN

IN THIS CONFIGURATION, TRANSISTOR "S" (THE SWITCH) IS WIRED IN PARALLEL WITH A 10K EXTERNAL RESISTOR. THIS PROVIDES A VOLTAGE DIVIDER NETWORK FOR NORMAL, NO ALARM (STAND-BY) OPERATION AT ABOUT 2.5V AT POINT "A." IF CURRENT FLOW STOPS, VOLTAGE RISES TOWARD 5V AT POINT "A" AND AN ALARM CONDITION. IF A NORMAL ALARM CONDITION OCCURS AND THE TRANSISTOR CONDUCTS (SWITCH CLOSES), A SHORT RESULTS AND POINT "A" FALLS 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

VOLTAGE

DIVIDER

NETWORK

_< 50ms

HIGH = ALARM

LOW = STAND-BY MODE

TTL-CMOS

EXTERNAL 10K

CONTROLS

GND

	INPUT
+5V	VOLTAGE
	A L A R M
3.3V
POINT A
1.65V	STAND-BY MODE
	A L A R M
0V
	TIME
ALARM	EQUIPMENT SIDE
WIRING SIDE	+5V

POINT A
	10K
	PIN 1	100K	Processor
			CIRCUITRY
	0.1uF
	PIN 2	0.1uF
10K	GND	GND
	NORMAL
	CURRENT FL0W
GND	NO ALARM

Figure 8a. Supervised Alarm Operation

22 Pelco Manual C690M-E (11/04)