The key of Profitable RS485 Standard > 자유게시판

Since the signal is attenuated as it travels, the "reflected" signal decreases in amplitude until its level stabilizes. Compatible with TTL/RS485 standard, converting the TTL signal into a balanced differential RS485 signal, supporting full-duplex communication. Waveshare TTL TO RS422 (B) is an industrial-grade rail-mounted electrically isolated TTL-to-RS485 serial converter. A USB to serial converter typically can convert USB to either RS232, RS485 or RS422 signals. A serial converter typically converts data between either RS232, RS485, RS422, USB or TCP signals, however some converter designs have other special conversion features. Actually many new devices designed today are designed with a RS232 serial port, often because RS232 is a very robust and reliable protocol which is fairly easy for program writes to integrate into their system. WARNING: Do NOT connect this device to a telephone system under any circumstances. This way, the lines will be biased to known voltages and nodes will not interpret the noise from undriven lines as actual data; without biasing resistors, the data lines float in such a way that electrical noise sensitivity is greatest when all device stations are silent or unpowered.

Slaves Receive: All devices on the network, including the slave devices, constantly monitor the voltage difference between lines A and B. When they detect a change, they interpret this as a bit of data.Slave Responds: If the master device sends a command that requires a response from a slave device, that slave device will wait until the master has finished transmitting, then change the voltage difference between lines A and B to send its response. A serial adapter, also referred to as a serial converter is a small electronic device which can convert one type of data signal into a different type of data signal. Two circuits are for transmitting and receiving the serial data, circuit "BA" (TX data on pin 2) and "BB" (RX data on pin 3). A number of circuits are for handshaking and other functions. Input terminal; /RE and DE are the enable terminals for receiving and transmitting respectively.

When the logic is 1, the device is in the sending state; the A and B terminals are the differential signal terminals for reception and transmission, respectively. The RO and DI terminals are the output of the receiver and the output of the driver respectively. When 5V drivers are used, the driver typically pulls one wire to circuit common, and the other wire to 5V (and vice-verse for the opposite data). The "idle" state (MARK) has the signal level negative with respect to common, and the "active" state (SPACE) has the signal level positive with respect to common. With Modbus, BACnet and Profibus, A/B labeling refers A as the negative green wire and B as the positive red wire, in the definition of the D-sub connector and M12 circular connector, as can be seen in Profibus guides. The third installation uses the same two computers as the second example, but they are separated by several thousand feet of wire, and one of the computers is sitting next to an arc furnace that draws several thousand amps when operating. 3 of Xnucleo are Serial to USB ports as default. NET application. A simple interface allows accessing data from a serial port using RS232 or multi-drop RS422 / RS485 serial ports.

When used as a converter, the master RS232 port provides bi-directional serial conversion to the 8 RS485 distribution ports. RS232 is the most common interface used to communicate serially but it has it's limitations. Even the RS232 standard is an older communication protocol it is still used by many modern devices in both business and consumer markets and is also often used for personal and office devices. Just because a protocol is used with a particular implementation of RS-232 or RS-485, does not mean it is part of the standard. When designing a network using RS-485, you should take into account several key factors:Network wiring: The manner in which the network is wired is crucial for successful signal transmission. RS422 and RS485 operate in differential mode using balanced cables. In addition to using the best cable, there are many different drivers, receivers, and transceivers available. In this case your best bet for defining how long the cable can be is to try it.