PLC systems are used to monitor and control operations, while HMI network systems allow interaction with machinery and control them. This includes speed control using Variable Frequency Drives (VFD) or inverters, as well as controlling simple PLC and HMI network systems. RS232 is an interface to connect one DTE, data terminal equipment to one DCE, data communication equipment at a maximum speed of 20 kbps with a maximum cable length of 50 feet. RS232 is without doubt the best known interface, because this serial interface is implemented on almost all computers available today. Best known for the simplicity of usage it provides, it also features embedded circuits protection features such as lightning-proofing, resettable fuse, ESD protection and TVS diode. Rs485 cable is essentially a signal cable with a twisted pair structure, additionally shielded with 2 layers of noise protection used in industrial communication. Because of this, the resulting noise current is many factors lower than with an ordinary straight cable.

In the straight cable, all noise current is flowing in the same direction, practically generating a looping current just like in an ordinary transformer. If the 8-core cable shipped with the device is used for RS485 communication, please trim the length and try to use a short wire to reduce noise interference. This utilization of a differential signal transmission mode effectively mitigates interference and enhances overall communication reliability. This ensures that all security-related information and incidents are transmitted quickly and with high reliability. It should be noted that the connection wires between each device should be kept as short as possible to minimize signal attenuation and interference, improving communication reliability. Let’s consider a simple example of an RS-485 network with one master device and two slave devices. The RS485 network must be designed as one line with multiple drops, not as a star or ring topology. Data travels in one or both directions around the ring. This topology offers efficient data transfer but can be disrupted if any single connection breaks, though redundancy protocols can mitigate this risk by providing alternative pathways for data.

This configuration facilitates efficient data transmission between devices while reducing the risk of signal distortion. The two-wire half-duplex system enables bidirectional data transmission between two devices, but not simultaneously. For instance, consider devices A and B. During a specific timeframe, data transmission is allowed from A to B, and once completed, data transmission from B to A can take place. RS485 at its core with 2 wires allows half-duplex data transmission. The diagram below shows potentials of the A (blue) and B (red) pins of an RS-485 line during transmission of one byte (0xD3, least significant bit first) of data using an asynchronous start-stop method. B- ports are connected to the corresponding ports of the next device using twisted pair cables. This allows RS-485 to implement linear bus topologies using only two wires. RS-485 is used for low-speed data communications in commercial aircraft cabins' vehicle bus. It is like the Universal Serial Bus (USB) or ethernet that we can find in many of our modern computers. You can find out more about the differences between RS485 and RS232 here. Accessories available are a 12VDC Switching Power Supply(Wall Wart), an enclosure, and a 7ft DB9F to RJ11/12 RS232 cable. In the central chemical dosing and dispensing system of China's Hingsen Semiconductor, the configuration comprises central chemical storage tanks coupled with dispensing systems at each process point, controlled through valve boxes to regulate the supply of chemical reagents.

The flow meters relay flow information in real-time to the central control system via RS-485, halting the supply once the specified amount of reagent is dispensed. Each valve box is equipped with a LORRIC paddle wheel flow meter to measure the flow rate of reagents. Within such a system, RS-485 serves a pivotal role as a bridge, what is rs485 cable establishing communication of flow information between the central control system and each valve box. That is why RS485 is currently a widely used communication interface in data acquisition and control applications where multiple nodes communicate with each other. RS-485 is a robust and versatile communication standard that is widely used in industrial applications. SenseCAP is a wireless sensing platform developed specifically for Industrial IoT, with applications in smart agriculture, smart cities, and other environmental sensing scenarios. This is an Industrial-grade 4G Data Logger from the Seeed’s SenseCAP product series. Powerful APP Support: SenseCAP Mate APP allows you to set the sensor templates and quickly turn the data logger into the sensor you want.