Along with the further development of Ethernet and its application in the field of industrial control, more and more products will provide Ethernet interfaces; however, for a certain period of time, devices that only provide serial communication will still exist. Therefore, to integrate serial devices via Ethernet, using a serial server is a good choice.
Serial server to solve the RS232/485/422 serial port to network port conversion, then converted to network port, the user software how to communicate with the converter it. Serial server provides software solutions roughly 4 kinds: virtual serial port, Socket programming, using DLL library, Modbus TCP.
Virtual Serial Port: That is, the user in the use of TCP/IP serial port server, without modifying the original software (serial devices should have a computer running on the equipment and communication software), the use of PUSR’s serial port server software programme can be virtualised similar to the COM4, COM5, and other virtual serial ports, and then through the software COM4, COM5 and the development of the serial port server binding. After that, the user software can open COM4, COM5, and use them just like the original hardware serial ports such as COM1. The use of virtual serial port for the existing serial port software users can be considered, but for users who have not yet designed the software, it is recommended to use socket programming, because socket programming is more efficient than the virtual serial port, but also do not need to install the driver.
Socket Programming: That is, the use of Windows/Linux and other operating systems on the development environment to develop network programs, directly and TCP/IP converter communication. The protocol is transparent transmission, that is, the network sends what the serial port receives, and vice versa. Users can choose VC, VB, Delphi, C# and other development environments provide socket programming, for example, to connect to the serial server in server mode is to call the Connect function, the parameters are the IP and port of the serial server.
Use DLL Library: DLL is a dynamic connection library that encapsulates the basic operation of the serial server using socket programming. Users can use DLL library to achieve the search, parameter setting, communication function of the serial server. Compared with Socket programming, DLL library is more powerful and easier to call. However, for users familiar with network programming, users still want to use Socket programming to design their own programs, and do not want their software with a large number of DLLs.
Modbus TCP: That is, the user’s software uses the standard Modbus TCP protocol. Serial to TCP/IP can directly convert the Modbus TCP data stream from the network port to Modbus RTU data stream, and the serial port side of the serial port server can communicate with the user’s serial port device in Modbus RTU mode. Serial Server can be used as Passerelle Modbus to realise standard Modbus TCP software access to standard Modubus RTU devices.
The Serial Server is a device used to transparently transmit TCP network packets or UDP data to and from the 1-channel RS232 and 1-channel RS485 interfaces. Low power consumption, equipped with ARM processor, fast speed. Integrated TCP/IP protocol stack inside the module can easily complete the network function of embedded devices. Integrated 10/100M adaptive Ethernet interface. Serial communication with the highest baud rate of 1024Kbps, with TCP Server, TCP Client, UDP, Httpd Client and other work modes products have been rigorously tested in the bank, highway, large corporate networks, busy networks with cameras and through the formation of optical fibre to Ethernet and other complex network environments have been successfully applied.