What is Serial Communication?

RS485 industry Standard use requirements, so when the distance between each device line is relatively long, it is easy to cause problems such as signal reflection and anti-interference ability, which leads to a decrease in the reliability of the control signal. 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? On the contrary, if the 120Ω matching resistance is not connected, what is rs485 cable just turn the 10th bit to OFF. You can connect the 120Ω matching resistance to the line by turning the 10th bit of the DIP switch to ON. The communication line should be as far away as possible from interference sources such as high-voltage wires, fluorescent lamps, etc. When the communication line cannot be avoided from interference sources such as power lines, the communication line should be perpendicular to the power line, not parallel, and cannot be bundled together, and use high-quality twisted-pair cables. The fundamental operation of RS485 involves two wires, enabling half-duplex data transmission.

RS485 at its core with 2 wires allows half-duplex data transmission. This ensures maximum protection for the inner core. Rs485 cable is essentially a signal cable with a twisted pair structure, additionally shielded with 2 layers of noise protection used in industrial communication. 3. Armored twisted-pair shielded cable ASTP-120Ω (for RS485 & CAN) one pair 18 AWG, the outer diameter of the cable is about 12.3mm. It can be used in places with severe interference, frequent rodent damage, and lightning protection and explosion-proof requirements. 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. 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. 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.

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. Network topology refers to the arrangement of various nodes (such as computers, servers, switches) in a computer network. Consequently, this arrangement restricts the system to half-duplex data transmission, where data can only move in one direction at a time between devices. Half-Duplex and Full-Duplex Modes: RS-485 can operate in both half-duplex and full-duplex modes. RS-485 does not define a communication protocol; merely an electrical interface. Designers create many devices and systems, such as sensors, controllers, and communication modules, to be compatible with RS-485. RS485 provides a means of interconnecting multiple devices in a series using a twisted pair of wires to facilitate data exchange. SenseCAP S2100 data logger can collect data from multiple sensors and transfer the data through the LoRaWAN network. For on-site debugging, you must carry a few converters that can connect to long distances and multiple loads, a commonly used computer notebook, a multimeter to test the circuit break, and a few 120 ohm terminal resistors.

Modbus is also a reliable protocol that can operate over long distances. 1. Long-distance communication - RS485 can communicate over much greater distances than other protocols, making it ideal for applications where data needs to be transmitted over long distances. This approach helps in canceling out common mode noise, ensuring better signal integrity, and allows for longer cable distances and higher data rates as compared to the RS232 interface. 6) What is common mode interference and differential mode interference? Differential mode interference is transmitted between two signal lines and belongs to symmetrical interference. 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. ● Use scientific and reserved solutions for 485 bus projects with long lines and heavy loads. 4) Why should the 485 bus adopt the hand-in-hand structure instead of the star structure? The star structure will produce reflected signals, which will affect the 485 communication. In actual construction use, users often use star connection. The method to eliminate differential mode interference is to add a bias resistor (matching resistance in the dome camera) to the circuit, and use twisted-pair wires; common mode interference is transmitted between the signal line and the ground, which is asymmetrical interference.