Weak current College】 【video four common problems and answers.

<br> As the urban development of the process, the complexity of the security environment, security monitoring works more and more use of fiber optic technology transfer images, sounds, data and other information, fiber optic transmission systems, key equipment-digital video by .customers. <br> <br> 1, optical transceiver optical path problem: <br> <br> Security monitoring engineering, optical fiber cables are laid by the user, typically a G652 single-mode fiber. As a result of system coverage are .not large, use standard (≤ 20KM) devices optical link loss are very rich, therefore, optical transceiver for optical path loss ever higher demands, but users often encounter no image, image, beating, image quality is poor, and so on, then .most of the problems out in the light path ends of pigtail, jumper or adapter, but rarely and backbone optical path. Common questions are: 1, optical fiber connector insert incorrect; 2, optical fiber connector core (ceramic) contaminated. The solution is .: 1, plug the connector or Exchange fiber jumpers; 2, with 99.9% ethanol cleans plug, socket core; 3, multimeter check camera video cable, judgment has no video signal. <br> <br> 2. optical transceiver data interface: .<br> <br> In order to meet the needs of security monitoring, the system of various equipment (matrix, hard, decoder) provides data interface RS-485, the format of data interfaces has the advantage that distances, load capacity, and .to the composition of four wires full duplex communication bus, line on any two devices can implement two-way communication, and four wire RS-422 bus you can only achieve the master, slave machine between the bi-directional communication between the machine does not .. The disadvantage is a enable, is three-State forms of communication, to bring instability or even "stuck" phenomenon. If there is no communication (out), you should find the following areas: <br> <br> 1. detection .of any control signal Exchange with multimeter 10V stalls dating controller (matrix, hard recording) output, see its RS-485 has no control signal output. <br> <br> 2. determine the optical transceiver RS-485 interface is normal, if .UA-B voltage zero is treated as normal. <br> <br> Head out to not be charged, this phenomenon is due to two reasons: a) RS-485 ports, A + B-reversed; b) system does not match .the impedance seriously. <br> 3. optical transceiver for switch quantity <br> <br> Switch quantity signal is TTL level of pulse train, it can control lights, alarm, relay, switch interface load capacity to control the size of the current ., such as EW series-load capacity of the switch quantity ≤ 1.5A. <br> <br> 1.EW series optical transceiver switch interface supports the Open button, but when you add in the following figure, the open method, normally closed .forms are supported: <br> <br> 2. switch the interface cannot directly parallel use, if there is a need to access only through the distribution circuits. <br> <br> 3. some customers using RS-485 bus transfer switch .quantity, according to our experience proves that this way is not desirable, the prolific work for a period of time (such as 3-4 days) that panic. Switch to the converter produced RS-485 has defects may be a problem. <br .> <br> 4. optical transceiver for transient noise hazards and measures <br> <br> 1. transient disturbances arise: transient disturbances resulting from the large inductive load such as motors, transformers, relays, switches, and lightning to occur, it .tends to static induction of intrusion optical transceiver. <br> <br> 2. harm of transient interference: interference due to its high frequency, duration, interference range large (hundreds or thousands of volts), it can burn optical transceiver for RS- .485 interface chip, chip, and other key parts of the body, but without leaving any traces, especially summer thunderstorm season, the destructive impact is large, so that users, businesses and manufacturers are very frustrating. <br> <br> 3. .response: Although optical transceiver manufacturers using various means of protection, such as bypass method (since recovery diode), absorption method (bi-directional suppression diodes, etc), separation (optocoupler), but still cannot completely eliminate the damage caused by transient disturbance ., damage to the frequent, RS-485 interface to users and manufacturers have resulted in great pressure. <br> <br> <br>.