select
When the video matrix host, you must first determine how many cameras do it need to control. Is it also expanded, add the number of cameras in the existing and future, select the number of inputs of the controller. For example, a residential community is currently only covered with 10 buildings. There will be 15 buildings in the later period. Each building is installed, then there must be 25 video input to control the host, (because most of the control host is input, The output module is expanded, and the input is incremented by 8 times), so it is necessary to select the 32 input host.
The number of output roads that select the controller is to see a few monitors in the monitoring room. For example, the example mentioned above, if the monitoring chamber requires at least 4 monitors, then the output is 4 or 5 output (more output does not affect performance, but the price increases) control host.
Currently controlled the hosts commonly used in the host, 8, 16, 32, 48, 64, 80, 96, 128 to 512, generally increment of 8 or 16; output from 2, 4, 5, 8, 16, 24 to 32 Generally, it is generally incremented by a multiple of 2 or 4.
There are a variety of control code for the host, most of which are not compatible, and must be matched with its series of products or devices that can be used. Such as decoders, assist followers, alarm interfaces, control keyboards,
multimedia
Software, etc.
The decoder function is to convert the control code of the host into an analog signal output: Provide a 24 volt or 220 volt AC voltage, a lens 12 volts DC voltage, auxiliary 24 volt AC voltage, 2 auxiliary switches, and a 12 volt stream powered by. The decoder is the most commonly used device in the control system. There is a pan / tilt or electric lens at the front end, and there is a decoder. The decoder is divided into indoor and outdoor types, and the outdoor type has a waterproof box and provides a wiper operating voltage. The 220 volt supply of the decoder must be provided when installing, and the address code of the decoder is driven to avoid conflicts. There is also a note of the working voltage of Yuntai, because there are 24 volts and 220 volts in the operating voltage of the cloud, and if it is not right with the decoder, it is impossible to work, and it is necessary to burn the cloud motor, resulting in unnecessary losses.
The decoder to the cloud station, the coupling line of the lens should not be too long, because the voltage of the control lens is about 12 volts, transmission is too far, which causes the lens to not control. In addition, since the multi-core control cable is more expensive than shielding twisted pairs, the cost will also increase.
Outdoor decoders should be waterproofed, and the waterproof gel seal is a good method at the inlet port, and the operation is simple.
From the host to the decoder, the shield twisted pair is usually employed, and the decoder can be connected in parallel in one line, with a total length of no more than 1500 meters (depending on the situation). If the number of decoders is too large, you need to add some auxiliary devices, such as increasing the control code distributor or in parallel with a matching resistor on the last decoder (subject to the manufacturer's instructions).
In addition to the monitoring room, there must be an operation of a cloud station, a lens, and a score control keyboard. Each host can be different from the number of partition keyboards. The function of the control keyboard is also different, and some can control the output of the monitor. Some can control shifts. The partition keyboard is generally coupled to the host.
Due to the development of computer multimedia technology, the monitoring system also has a trend towards it. Most vendors have a computer interface when designing the monitoring host, and communicates with the computer's serial port communication, insert a video capture card on the computer. To view the image, insert a sound card to listen to the sound. Multimedia control software generally has the following functions: set the model of the system control host, set the communication port, set the system password, set the operator's operation level, draw electronic map, set the nature of the front-end camera (whether to bring a pan / tilt, electric lens), Existing maps are increasing and deleting modifications, preventing the alarm detector to prevent and disarm, control video switching, pan / tilt rotation, lens focus, auxiliary switch closure, and the like. Since the multimedia software operation interface is good, the operator is easier to understand, and it has now been widely used. Installation consideration: Since the monitor host output signal is 485 yards, it is impossible to compete with the analog signal, so it is necessary to do a good job in the device when installing, ensuring that there is no strong feedback to the communication port during the loop, otherwise it will burn the communication chip. Make the host can't work.
