EIA-485 Bus Interface Description, RS485 Description > 자유게시판

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These USB to RS485 converter and USB to RS422 adapters are most often used for connecting a RS485 or RS422 device to a personal computer. If you ever wanted to connect to device in the same building (e.g. to machinery on production hal) and to you have to go to it to connect your computer. Since most computers do not have a RS485 or RS422 port, but they do have a USB port, you can use a USB to RS485 converter or USB to RS422 adapter to interface between your computer and your device. The standard USB RS485 converter / USB to RS422 adapter is a non-isolated adapter which is used for many business, RS485 standard office and personal devices. A RS232 - RS485 converter is often used in industrial data acquisition and control applications where multiple serial devices communicate with each other through a converter. Can control multiple ports simultaneously. Watch Dog function ensuring the control of selected applications in equipment. If applications require connecting multiple systems, higher data rates, more noise immunity, and the distance is long, then RS-485 is a more suitable candidate.

The Lumen's upcoming powered feeders will communicate using RS-485, a multidrop serial bus common in industrial applications. Additionally, RS-485 drivers are designed to detect and recover from bus contention conditions, where two or more drivers try to drive the bus at the same time. These factors are discussed in more detail in The UART Wildcard: Modem Handshaking Signals. Different Unit Loads in transceivers allow more devices on a network, including full, half, quarter, or eighth-unit load circuits. Let’s say, Mr. X wants to connect a modem to his PC and the distance between the two devices is a little over 15 feet. The RS485 and RS232 serial communication protocols have been in use for over 50 years and are still widely used throughout business and industry. Some of these are already pre-prepared and shipped to the customer's request with the device. 5 meters. The advantage of 2-wire technology lies essentially in the multi-master capability, whereby each device can in principle exchange data with any other device. In other words, between Devices A and B, within a given time frame, only Device A is allowed to transmit data to Device B. Following the completion of this transmission, data transfer from Device B to Device A can then commence.

So in order to transfer data from a RS232 serial interface engineers need a converter to be able to connect to a RS485 or RS422 interface. Why use a RS232 - RS485 /RS422 converter? The same way "the customer is king" in the business world, the application is king when choosing which protocol to use. The respond seed is quite fast for customer satisfaction. Without termination resistors, reflections of fast driver edges can cause multiple data edges that can cause data corruption. EIA-485 only specifies electrical characteristics of the driver and the receiver. In contrast to EIA-485 (which is multi-point instead of multi-drop), EIA-422/V.11 does not allow multiple drivers but only multiple receivers. EIA-485 (formerly RS-485 or RS485) is an OSI Model physical layer electrical specification of a two-wire, half-duplex, multipoint serial connection. Should also be used on RS-485 networks if the driver is always enabled. This resistor will also make any length of cable, even a short length, look like the characteristic impedance of the cable (120 Ω in the model) to the driver. Adding a resistor to the end of the cable that matches the value of the cable's impedance will absorb the signal traveling down the line and reduce or prevent reflection.

The value of each termination resistor should be equal to the cable impedance (typically, 120 ohms for twisted pairs). Ideally, the two ends of the cable will have a termination resistor connected across the two wires and two powered resistors to bias the lines apart when the lines are not being driven. Digital panel meters are used to perform digital processing on or conversion and display of voltages, currents, and other analog signals and pulse signals. There is a front panel IP54 and 4keys silicon membrane keyboard available with monochromatic LCD display having dimension of 128x64. You will also get RGB backlighting and color selectable option by parameter. 12 V and -7 volts will allow correct operation of the receiver. Slew rate limiting drivers will reduce the rise time and decrease the ringing of an unterminated line. RS485, also known as TIA/EIA-485 is a standard serial communications protocol defining the electrical characteristics of a serial converter, drivers and receivers for use in balanced RS485 digital multipoint systems. Philips Dynalite provides several different methods for interfacing with other services, such as building management systems (BMS), projector controllers and audio-visual controllers, blind motors and other third components. A single LON message can be sent that can change the Philips Dynalite system to operate between after hour and trading hours mode.