The alarm host system is a system that can automatically detect the intrusion behavior in the arming monitoring area, generate an alarm signal, and prompt the on-duty personnel to the area where the alarm occurs, and display possible countermeasures. The alarm host is an important facility to prevent robbery, theft and other accidents.
First, the working principle of the alarm host system
The alarm system consists of alarm signal input devices (usually detectors, or manual trigger devices such as emergency buttons), alarm host (signal processing), alarm signal output devices (relays, such as sound and light alarm equipment, etc.), control devices (such as keyboards, remote controls, etc.), management platforms (platform software, client software, mobile software), alarm receiving center (network, telephone, wireless), etc.
The front-end detector includes passive infrared, infrared plus microwave double detection, infrared through-beam, infrared guardrail, manual alarm, fire house detection, glass breakage, etc., which are suitable for different environments according to different functions. The front-end detector is the sensor of the alarm system, and the detection of the external alarm situation by the alarm system is completed through the front-end detector. As far as the connection and signal transmission between the front-end detector and the alarm host are concerned, in the final analysis, it is a switching signal transmission and reception process. The so-called switching signal is the process of opening and shorting an electrical circuit.
In fact, the working principle of alarm host and alarm detector is very simple, but why many people in practice cannot be properly configured and used, in fact, some key basic knowledge is not well understood. Let’s talk about the wiring knowledge of the alarm host
Second, how to wire the alarm host system
Alarm host to normally closed working mode as an example, when the system is powered on normally, if the detector is powered off or triggered by the alarm situation, the relay in the detector sends out an action, the contact changes from closed state to open state, when the alarm host detects this change in the corresponding defense zone, it will take corresponding reactions according to the current state settings (including ignorance, alarm, signal output, etc.).
Normally closed detector wiring method:
1. The NC and COM of the detector are terminated by the Z and G of the host defense area;
2. The detector end is connected in series
The detector terminal “ALARM(NC,COM)”, a resistor in series is connected to the “Z, G” terminal of the alarm host, regardless of positive or negative
Normally open detector connection
Alarm host to normally open working mode as an example, when the system is powered on normally, if the detector normally open contact point is triggered by the alarm situation, the relay in the detector sends out an action, the contact from the open state to the closed state, when the alarm host detects this change in the corresponding defense zone port, it will take corresponding reactions according to the current state settings (including ignoring, alarm, signal output, etc.).
Normally open detector wiring method:
1. The NO and COM of the detector are connected to the Z and G of the host respectively;
2. The detector end is connected in parallel
The detector terminal “ALARM(NC,COM)” is directly connected to the alarm host “Z, G” terminal, regardless of positive and negative, and the host “Z, G” terminal is shorted by resistance
The summary is as follows
Normally closed loop (NC):
The short circuit is normal, and the open circuit alarm. The disadvantage of this circuit formation is that if someone shorts the line, the probe loses its effect. The alarm host cannot identify the human short circuit.
Normally open circuit (NO):
Short circuit alarm, open circuit is normal. The disadvantage of this circuit formation is that if someone breaks the line (cuts the signal line), the probe loses its effect. The alarm host cannot identify the section that is human.
Third, the alarm host expansion module wiring
The alarm host expansion module is divided into two types, one is the “M-BUS” protocol expansion module and the other is the “485” protocol expansion module
“M-BUS” protocol extension module
It is connected through the host M-BUS bus, the bus port has a 36V voltage to distinguish between positive and negative, the connection method adopts “hand-in-hand daisy chain”, and the detector uses “10KΩ” resistor
(Common “M-BUS” protocol expansion modules are: ARM801, ARM802, ARM808)
“485” protocol extension module
The module is connected through “A2, B2” on the alarm host, the module needs to be independently powered, and the module is connected to the detector using “2.2KΩ” resistance; The module has “red, black, blue, yellow, green” 5-core wire. Among them, “red and black” are connected to the positive and negative of the power supply. “Green and yellow” are connected to the 485 bus respectively: green (positive), yellow (negative). “Blue, black” connected to the detection equipment alarm output normally closed. The black line is GND, and the COM connection black line of the detector is shared with the power ground.
Normally open detector connection