이름 : Tayla
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예식일 : A short Course In What Is Rs485 Cable
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One of the effective ways to eliminate common-mode interference is to use the shielding layer of the 485 communication line as a ground wire, connect the equipment in the network such as machines, computers, etc., and connect them to the ground reliably from one point. Only when the 485 communication distance exceeds 300 meters, the terminal resistance should be added at the beginning and end of the 485 communication. Without termination resistors, signal reflections off the unterminated end of the cable can cause data corruption. If the branch line is not connected to the terminal, there will be reflected signals, which will cause strong interference to the communication. In the same network system, use the same type of cable to minimize the number of contacts in the line. 2. It is not allowed to use a network cable with a wire diameter that is too thin, which will reduce the transmission distance and reduce the equipment that can be connected. 2. Ordinary twisted pair shielded cable STP-120Ω (for RS485 & CAN) one pair 18 AWG, the cable outer diameter is about 8.2mm. Suitable for indoor, pipeline and general industrial environment. It should be judged according to the model of the chip in the 485 converter and the model of the 485 device chip, and the load capacity can only be determined according to the chip with a lower index.

3) How should the 485 communication line be routed? The specifications of the shielded twisted pair used are related to the distance of the 485 communication line and the number of connected devices, as shown in the following table. 7) Under what circumstances should a terminal resistance be added to the 485 bus? You can connect the 120Ω matching resistance to the line by turning the 10th bit of the DIP switch to ON. The 485 communication line is composed of two twisted-pair lines. Generally, there are three levels of 485 chip load capacity-32 units, 128 units and 256 units. In fact, not all 485 converters can be equipped with 128 devices. Some people say that the 485 bus can carry 128 devices for communication. If there are many load 485 devices, the wire impedance is not up to the standard, the wire diameter is too thin, the converter quality is poor, the equipment lightning protection is complicated, and the baud rate is increased. 1. Ordinary twisted pair shielded cable STP-120Ω (for RS485 & CAN) one pair 20 AWG, the outer diameter of the cable is about 7.7mm. Suitable for indoor, pipeline and general industrial environment. In theory, the longest transmission distance of RS485 can reach 1200 meters, but the transmission distance in practical applications is shorter than 1200 meters.

The length of the branch line from the bus to each terminal device should be as short as possible, generally not exceeding 5 meters. 1) What kind of communication line should be used for 485 bus? ● Carry out construction strictly in accordance with the 485 bus construction specification to prevent any fluke. ● If the communication distance is too long, such as over 500 meters, it is recommended to use a repeater or 485 HUB to solve it. Especially when the number of devices on the 485 bus is small. RS485 cable is a type of communication cable used in industrial applications to transmit data between devices over long distances. In addition to its physical characteristics, RS485 cables also have specific electrical properties that allow for differential signaling, what is rs485 cable enabling reliable data transmission over longer distances compared to other communication protocols. From the latest point of view, advancements in technology have led to the development of enhanced RS485 cables that can support even higher transmission speeds and longer distances.

Digital communications networks implementing the standard can be used effectively over long distances and in electrically noisy environments. At least 0.4mm square or use a standard network cable. Category 5 (Cat 5, Cat 5e, and Cat 6) cables are the most common Ethernet cables in use today. The transmission speed of RS485 cables can vary depending on factors such as cable length, baud rate, and the quality of the cable itself. Up to eight relays can be added. In the transmission process, the method of adding relays can be used to amplify the signal. Differential mode interference is transmitted between two signal lines and belongs to symmetrical interference. ● Use scientific and reserved solutions for 485 bus projects with long lines and heavy loads. The use of shielded twisted-pair cables helps to reduce and eliminate the distributed capacitance between the two 485 communication lines and the common mode interference generated around the communication lines. 5) Is there a connection point from device to device on the 485 bus?