RS-485 Cables for BACnet and Modbus > 자유게시판

Stable connections play a crucial role in managing and controlling access to secure areas, optimizing system performance. RS485 has two-wire and four-wire connections. Nowadays, the two-wire connection method is mostly used. Although many people believe it is a two-wire network, it is not. Some people say that the 485 bus can carry 128 devices for communication. The condition is that the communication wire is high-quality and meets the standard, the baud rate is 9600, and only one 485 device is loaded, so that the communication distance can reach 1200 meters, so the actual and stable communication distance of the 485 bus is usually less than 1200 meters. That is to say, the maximum transmission distance of RS485 can reach 9.6 kilometers in theory. The transmission distance of multimode fiber is 5-10 kilometers, while the transmission distance of single-mode fiber can be up to 50 kilometers. In theory, the longest transmission distance of RS485 can reach 1200 meters, but the transmission distance in practical applications is shorter than 1200 meters.

According to the 485 bus structure theory, under the premise of an ideal environment, the 485 bus transmission distance can reach 1200 meters. The specific transmission distance depends on the surrounding environment. When using the RS485 interface, for a specific transmission line, the maximum cable length allowed for data signal transmission from the RS485 interface to the load is inversely proportional to the baud rate of the signal transmission. RS485 has no specific physical shape. An RS485 system should ideally consist of a single linear cable (with no branching) with 120-ohm resistors linked across the two wires at each end. Control and monitoring systems: A single pair of rs485 signal cable can connect up to 32 devices, with a signal transmission distance of up to 1200m. Therefore, using rs485 cables is an ideal choice for industrial control and monitoring systems, especially those with large-scale and high dispersion. Because it may be used at high speeds, over long distances, in electrically loud settings, and with multiple devices on the same bus, RS-485 is a good choice for most serial interface applications. Up to 32 nodes can be connected on the same bus. With multi-drop (many devices on the same bus) and extensive cabling lengths, it's easy to see why the RS485 is so popular in the industrial and automation worlds.

How many devices can be connected to a bus? Up to 32 slaves can be connected in the system. Section 4 defines the electrical characteristics of the generator (transmitter or driver), receiver, transceiver, and system. It is IP66 rated, waterproof and dustproof, which makes it ideal for long-term remote environmental monitoring in indoor and outdoor severe environments. Ordinary twisted-pair cables can be used in general occasions, and shielded coaxial cables can be used in environments with relatively high requirements. The 485 communication line is composed of two twisted-pair lines. This allows RS-485 to implement linear bus topologies using only two wires. Powerful APP Support: SenseCAP Mate APP allows you to set the sensor templates and quickly turn the data logger into the sensor you want. Easy to Use: The sensor can be used out-of-box through Bluetooth configuration, and users receive the data on the phone, cloud servers, and different platforms in just a few clicks. Network topology refers to the arrangement of various nodes (such as computers, servers, switches) in a computer network. Most engineering companies are accustomed to using Category 5 network cables or over Category 5 network cables as 485 communication lines, which is wrong.

The termination also includes pull up and pull down resistors to establish bias for each data wire for the case when the lines are not being driven by any device. 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. 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. Access control systems: Rs485 cables are mainly used to connect and transmit data between access control devices such as security gates, RFID cards, or time attendance machines and the control center. Devices (Device 1, Device 2, Device N) are connected in series, forming a daisy chain topology. RS-485 is also used in theater applications, what is rs485 cable where a large number of devices are spread out across a large area. You can find out more about the differences between RS485 and RS232 here. In the transmission process, the method of adding relays can be used to amplify the signal.