If a Star Configuration is Unavoidable > 자유게시판

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. It also allows manual flow control if needed. This allows RS-485 to implement linear bus topologies using only two wires. This helps to minimize the impact of electromagnetic interference, causing the voltage between the two wires to deviate. In RS485 standard, data is transmitted via two wires twisted together also referred to as "Twisted Pair Cable". 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. Anti-inteference layer: Rs485 cables are designed with 2 anti-inteference layers to shield the internal conductors. If you are familiar with RS232, what is rs485 cable then you may already know a little bit about it. Let’s talk about what we now know about RS485.

Let’s say you were monitoring a water pump filling a vessel. You decide that the water is not filling fast enough to keep up with demand. RS485 main advantages as compared to other serial communication are tolerance to electrical noise, lengthy cable runs, multiple slaves in one connection, and fast data transmission speed. All of this allows you to speed up the VFD that controls the speed of that water pump. The PLC is also connected to the VFD via RS485. This includes speed control using Variable Frequency Drives (VFD) or inverters, as well as controlling simple PLC and HMI network systems. First of all we see that the speed of the differential interfaces RS422 and RS485 is far superior to the single ended versions RS232 and RS423. When the cable is twisted, we see that in some parts of the signal lines the direction of the noise current is the oposite from the current in other parts of the cable. Electric noise can cause all kinds of problems for electronics.

This allowed for electrical noise to cause interference. Rs485 cable is essentially a signal cable with a twisted pair structure, additionally shielded with 2 layers of noise protection used in industrial communication. This ensures maximum protection for the inner core. 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. We will concentrate on the RS485 interface here. You can find out more about the differences between RS485 and RS232 here. Serial communication also has a deterministic behaviour to avoid collisions of data packets, making it more reliable for a linkage system with many devices. The greatest feature of RS485 is the fact that you can connect up to 32 devices on one system. RS485 can handle up to 32 connected devices. RS232 could only handle one.

RS232 could only handle one at a time. What made it such an advancement over RS232 was the fact that it could transmit not only a single device to device transmission, but also a communications bus to connect multiple devices at once. RS485 has many advantages over other standards, especially when it comes to applications in noisy industrial environments. However the other standards that have been introduced more recently provide higher levels of performance that are very useful in may applications. It is faster and much more versatile than the older RS232. Much like RS232, RS485 doesn’t have an actual standard connector. Many laptop computers incorporate a serial interface, and it was also used on many printers, although much less so now. RS232, RS422, RS423 and RS485 are serial communication methods for computers and devices. Just like it’s older brother RS232, RS485 is a form of serial communication. You aren’t limited to fifty feet of cable like with RS232.