Serial device server is between RS-232/485/422 to TCP / IP communications for data conversion interface converter. It provides RS-232/485/422 serial port and terminal TCP / IP network transparent two-way data transmission, providing serial to network functions, RS232/485/422 transfer network solutions. It allows serial devices can now join the network.
With the widespread popularity of the Internet, “Let all the devices connected to the network” has become the consensus of the world’s businesses. In order to keep up with the trend of network automation, and will not lose its competitive edge, we must establish a high-quality data acquisition, production monitoring, real-time cost management of networked systems. Use to achieve TCP / IP serial data stream based on control and management of hardware devices, without having to invest a lot of manpower and material resources to be managed, replaced or upgraded.
Serial device server makes TCP / IP-based serial data stream as possible, it will connect multiple serial devices and serial data stream can be selected and processed data to the existing RS 232 interface is converted into IP port data, then IP-based management, IP-based data access, so you can send the traditional popular IP serial data channel, without prematurely out of the original equipment, thereby increasing the utilization of existing equipment rate, saving investment, but also to simplify the complexity of the wiring on the existing network infrastructure. Serial device server to complete a connection-oriented RS232 link and connectionless Ethernet for communications between the data storage control system for a variety of data processing, process serial data stream from the serial device, and format conversion, making the data frame can be transmitted in Ethernet; data from the Ethernet frame to judge, and converted into serial data delivered in response to serial devices.
Internal integration ARP, IP, TCP, https, ICMP, SOCK5, UDP, DNS and other protocols. RS-485/422 provides automatic data conversion control. RS232/422/485 serial interface triple, 300-230.4KBPS baud rate. Support for dynamic IP (DHCP) and static IP, gateway and proxy server support, data can be transmitted over the Internet. Provide transparent bidirectional data transmission, users do not need to make any changes to the original system. All serial ports built-600W lightning. 10 / 100M Ethernet, automatically detect straight-through or crossover cable. It can support multiple connections.
Way of working:
1. Server mode: In this operating mode, Serial Device Server as TCP server, converter platform program listens for connection requests on the specified TCP port, the approach is more suitable to a converter program to establish a connection with multiple platforms ( A converter can not establish a connection with multiple platforms program).
2. Client mode: In this operating mode, Serial Device Server as TCP Client, converter initiative program requests a connection to the internet on power, the approach is more suitable to multiple converters at the same time to establish a connection to a platform program.
Communication modes:
1. point communication mode: In this mode, the converter used in pairs, one as a server, one as a client to establish a connection between the two, two-way transparent transmission of data. This mode is suitable for the bus connection between two serial devices engineered to TCP / IP network connection.
2. Use virtual serial communication mode: In this mode, one or more converters to establish a connection with a computer, two-way transparent transmission of data. By the virtual serial port software management following converter on your computer, you can achieve a virtual serial port corresponding to a plurality of converters, N corresponds to the M virtual serial converter (N <= M). This mode is suitable for serial devices controlled by computer 485 or 232 devices.
3. Web-based communication mode: In this mode, the application on the PC SOCKET protocol based communications program written in the converter settings can be selected directly support SOCKET protocol.
In the realm of Industrial Internet of Things (IIoT), serial servers have emerged as indispensable components, facilitating seamless integration and communication between legacy serial devices and modern network infrastructure. For those embarking on networking applications, understanding the versatility and significance of serial servers is crucial to achieving robust and efficient system integration.
Serial servers act as a vital bridge between traditional serial devices (RS-232, RS-422, RS-485, etc.) and modern Ethernet networks. This enables devices that were previously isolated or limited to point-to-point connections to be integrated into broader network ecosystems. By converting serial data into IP-based packets, serial servers facilitate remote access, centralized management, and real-time monitoring of these devices over long distances.
In industrial automation scenarios, serial servers streamline the data flow between sensors, actuators, PLCs, and other industrial controllers. They enable remote monitoring and control of machinery, optimizing production processes and enhancing operational efficiency. For instance, by connecting serial sensors to a serial server, production line data can be transmitted wirelessly to a supervisory control and data acquisition (SCADA) system, enabling operators to track performance metrics, detect anomalies, and trigger corrective actions promptly.
In the context of smart buildings, serial servers play a pivotal role in integrating disparate systems such as lighting controls, HVAC systems, security cameras, and access control panels. By converting serial signals from these devices into IP-based communication, serial servers facilitate centralized monitoring and management of building systems from a single platform. This enhances energy efficiency, occupant comfort, and overall security, while reducing maintenance costs and improving response times to emergencies.
For remote monitoring applications, serial servers enable real-time access to data from remote sites or hard-to-reach locations. In transportation systems, for example, serial servers can connect traffic signals, toll gates, and surveillance cameras to a central command center, allowing for centralized monitoring and control of traffic flow. Similarly, in utility grids, serial servers can facilitate remote monitoring of substations, transformers, and other critical infrastructure, enabling quick response to faults and optimizing energy distribution.
In the healthcare sector, serial servers are essential for integrating medical devices into hospital information systems (HIS) and electronic health records (EHR). By connecting serial-based medical equipment like ECG machines, blood pressure monitors, and lab analyzers to serial servers, patient data can be transmitted securely and reliably to central databases for analysis, storage, and sharing among healthcare providers. This improves patient care, enhances decision-making capabilities, and supports regulatory compliance.
emote monitoring and control, and integrating medical devices into healthcare information systems. For those embarking on networking applications, understanding and leveraging the capabilities of serial servers is key to achieving robust, scalable, and efficient system integrations.
Other applications include, time and attendance system, Shoufan systems, POS systems, building automation systems, self-service banking system telecommunications room monitoring, power monitoring.
Hardware system is the foundation of the whole system function, is the key to the whole design implementation.
Key to the whole serial device server that converts serial data packets and TCP / IP data packets between the two sides as well as the existence of data because of different rates of speed matching problem, the serial port server implementation, must also be made important consideration in the design and whether the selected device can perform these functions.
(1) hardware system modules
Technical difficulties in developing the design and the selected device encountered was how to use the processor serial data information TCP / IP protocol processing, so that it becomes possible transmission of IP packets over the Internet. Currently a lot of time to solve this problem using the 32-bit MCU + RTOS program, this program is the use of 32 high-end microcontroller software development on RTOS (Real Time Operating System) platform, TCP / IP in embedded systems protocol processing. The disadvantage is: SCM higher prices, longer development cycle; RTOS developers need to buy expensive software development capabilities to developers demanding.
Learn the advantages and disadvantages of the above programs, we decided to port the server hardware design is divided into several modules, which is several modules main processing module, serial data processing module and Ethernet interface and control module to have completed the serial device server functionality .
In the selection of the device, the choice of Intel’s 801,086 chip as the main processor chip processing module, which is a very suitable for high-performance embedded applications, 16-bit microprocessor highly integrated, low-power consumption.
Taking into account both sides of the lower speed serial data rates and Ethernet data transfer rate caused by the mismatch problem, we decided in line with large-capacity memory bus specification as data storage; the main processing module also relates to a data line / address lines multiplexed serial to parallel conversion, an interrupt signal decoding device, the clock signal generation, signal access control and other functions, if the use of different devices to complete, will inevitably lead to many problems such as delay inequality, we use a piece large-capacity high-performance programmable logic device to complete the functions of the above mentioned, the advantage is that we ensure the stability and reliability of programmable logic devices and programmable feature allows for the processing of signals in space more big, and has the advantage of the upgrade.
Ethernet interface and control module plays a very important role in the serial device server hardware inside, it processes the IP packets from Ethernet, taking into account the principles of universality, we use a Ethernet controller chip to complete these function, and add a piece of AT24C01 to store Ethernet controller chip status in the main processing module. Through the main processing module for the Ethernet controller chip data and register read / write, we can complete the IP packet analysis, working solution / pressure package.
Serial data processing module to complete the level for serial data format conversion and data stream processing, judgment start bit serial data and stop bits, complete extraction of the data and parity bits. General design is used in a UART MAX232 and design ideas, where we also follow this design concept, but we use the integrated MAX232 + UART chip functionality, small size, low cost, low power consumption, and the use and SPITM / QS-PITM / MICROWIRETM compatible serial interface, saving board space and microcontroller I / O ports.
The advantage of this modular approach is that: the use of high-speed 16-bit microcontroller, and peripheral devices, low system costs; and the use of Intel’s development platform, can greatly shorten the development cycle and reduce development costs.
(2) hardware workflow and application architecture
First, the main processor to initialize the network and serial devices, when data from the Ethernet transmission over packet processor to analyze, and if ARP (Address Resolution physics) packets, then the program into the ARP handler; if IP data package and transport layer uses UDP, the port is correct, then that data packet is correct, data unpack the data portion by the corresponding serial output port.
Conversely, if the received data from the serial port, the data is packaged in accordance with the UDP format, into Ethernet controller chip, its output data to the Ethernet. May know, the main processing module processing TCP / IP network layer and the transport layer, link layer partially completed by the Ethernet controller chip. Application layer delivery system to handle software, users can process data received on demand.
Depending on the structure of the hardware system and different functions, we can be a hardware system is divided into the following several modules.
(1) Main processor module
This module is the core part of the server’s serial port, mainly by the main processor, programmable logic devices, data and program memory and other devices.
The main processing module to complete the main functions are: to establish a data link between the serial data and Ethernet IP data; controlling reading and writing through the Ethernet control chip to achieve receive and transmit IP data packet; determining a serial data stream format, complete the serial device selection and designation of the serial data stream format; control rate serial data stream and IP data packets between the control, data buffering; for UART and Ethernet control chip registers read write operations, and store and forward device status; the completion of the serial-parallel converter 16 bus data; complete bus address latch function; the completion of each port and each memory device chip-select functions; complete the interrupt status of each serial port discrimination, etc. Features.
(2) Ethernet interface and a control module
The module consists of an Ethernet interface and Ethernet control section parts.
Ethernet interface is partially completed function serial device server and Ethernet interface circuit, a controller module has controls for all the role of the entire interface circuit to a coordinated manner with the follow-up circuit complete Ethernet transceiver functions.
Ethernet control in part by the receiving end and the originator of the composition, among them there are Ethernet status detection and control unit, as well as send and receive coordination controller, shown in Figure 5. Since Ethernet is half-duplex, so this part must be ready to monitor the status of Ethernet and Ethernet as needed to control, but also to coordinate the work of a good state of internal transceiver side of the circuit.
Ethernet detection unit and transceiver coordination controller is to complete this function. Ethernet controller interface state detection unit and Ethernet interface, the state of the interface to send and receive coordination controller, while the control signal from the controller will coordinate processed and sent to the Ethernet interface controller to control interface state.
At the receiving end, the received serial data stream signal through the main processing module string and conversion and encoding, Ethernet control unit controls each section coordination, the resulting address, data, write to the RAM write control signal processing unit . Accordingly, work processes, and the originator of the opposite receiving end.
