RS485 communication technology is used a lot in engineering, and its main advantages are as follows:
1. The wiring is simple: only 2 wires are needed, and now the shielded wire interface of the network cable is generally used.
2. The communication distance is long: since the differential mode communication method is adopted, the communication distance is farther than that of RS232.
3. It can support multi-machine networking communication: compared with RS232 one-to-one connection. RS485 can mount multiple terminals online, and realize multi-machine communication by query-response.
However, RS485 now often needs to be converted to Ethernet, which is converted to TCP/IP, after analyzing, the main reasons behind are:
1. Ethernet can be connected to the Internet so that long-distance communication can be realized, and monitoring can be achieved on a global scale, which is impossible for RS485.
2. When multiple RS485 devices are required to be connected to a computer, the traditional way is to use multiple serial ports. That is to use serial port expansion on the computer to realize multiple RS485 serial ports. After using RS485 to Ethernet, you can leave the RS485 interface to the site, and the monitoring computer only keeps one network cable at the end, which is convenient to use.
To realize RS485 to Ethernet (ie 485 to network port), it mainly needs a hardware converter and a software driver. There are two types of hardware converters: serial device server (serial device network server, serial device communication server) and serial network module.
The RS485 serial device server is equipped with a housing that connects existing 485 devices to Ethernet. It is suitable for the network transformation of existing RS485 serial devices. RS 485 serial network module is not equipped with a housing, it can be understood as an embedded RS485 to Ethernet module, by using the module solution, the module can be integrated into the user equipment to realize the integration of the serial device server and the device. In terms of the price, the module solution is cheaper than the serial device server solution.
The hardware of the serial device server realizes that the RS485 interface is converted into a TCP/IP interface (network interface), then the virtual serial port driver of the computer side can be used to virtually convert the TCP/IP connection into a serial port again. The virtual serial port driver can virtualize a virtual serial port number such as COM5 and COM6 in the driver layer of the computer, and bind the remote serial port server to these virtual serial ports. In this way, when the user serial program opens the virtual serial port, it can communicate with the remote serial server, that is, communicate with the serial device.
After using the hardware and software system of the RS485 to Ethernet solution, the user's 485 device is equivalent to network expansion, and the original hardware and software programs do not need to be modified.
USR-TCP232-304 is a serial RS485 to Ethernet server, used for data transparent transmission. USR-TCP232-304 is a low-cost serial device server, whose function is to realize bidirectional transparent transmission between RS485 and Ethernet. USR-TCP232-304 is internally integrated with TCP/IP protocol. User can apply it to device networking communication.
1.DHCP and DNS function
2.Built-in webpage for configuration
3.Support httpsD Client
Important point: It does not support Modbus RTU to Modbus TCP