Application of serial port server in broadcast and television transmitter room

With the continuous improvement of radio and television transmitter technology, the working conditions of various components of the transmitter can be automatically monitored and controlled. Collect and store the operating data of the transmitter equipment, display the data in various forms, and facilitate the check-in personnel to monitor the working status of the equipment; manually and automatically generate data reports; abnormal and fault alarms and automatic records; check-in personnel log management, record equipment maintenance information; data is stored in the database, providing complete query and reporting functions; control the transmitter power on and off, and adjust the operating parameters of the equipment. Real-time monitoring of various parameters of various equipment such as transmitter room environment monitoring, remote control and telemetry. Diagnose and handle faults, record and analyze relevant data, so as to achieve the purpose of less or no one on duty, and centrally monitor, maintain and manage the equipment.

In the past, the host was directly connected to the device through a converter, as shown in Figure (1).

Generally, the number of serial ports on a host is very limited, and the number of devices that can be controlled is also very limited. However, in many applications, the host needs to have a large number of serial ports to connect multiple serial devices, so as to realize the control of these devices by the host. In some cases, the number of serial ports may reach dozens to hundreds. If we follow the previous practice, we need to configure a large number of hosts, and there are great defects in system maintenance, management, real-time monitoring of the computer room, and system wiring. This not only wastes resources but also fails to achieve centralized management.

1 Overview of the new system

With the development of the network, the application of IP network based on TCP/IP protocol has been widely popularized. By using the serial port server device Hutone Model1608, the existing serial port devices can be immediately connected to the Ethernet, and the real-time monitoring of the devices at each point can be realized through the TCP/IP-based network, achieving a safe, simple and effective transmission method, and realizing centralized and convenient management. The system is mainly a solution based on the existing Ethernet. Since the transmitter has a lot of real-time monitoring data, the use of a multi-serial port server to directly connect each transmitter device to the network or merge a few devices to the network can shorten the time for the system to query the transmitter each time. The equipment of the computer room environment monitoring system such as air conditioners, temperature and humidity sensors, smoke and dust probes, and voltage-stabilized power supplies are connected to the multi-serial port server through the RS485 hub to achieve networking, as shown in Figure (2).

2 Hutone Model1608 Data Transmitter Software and Hardware Technical Overview

Hutone Model1608 data transmitter is a serial-to-Ethernet product of Beijing Rongcheng Intercommunication Technology Co., Ltd. It mainly completes the conversion of Ethernet TCP/IP protocol and transmitter and room environment equipment field bus RS-232, RS-485, RS-422 and other protocols at the network layer, completes the interconnection between Ethernet and field bus network, and realizes data exchange between Ethernet and field bus network. In this intelligent system, various serial port subsystems of the radio and television transmitter room are organically integrated into one by using the existing network and Hutone Model1608 data transmitter. Using Hutone Model1608's TCP/IP Server/Client Ethernet-based communication means of intelligent room control technology, it can integrate multiple functions such as transmitter monitoring system, environmental monitoring, access control system, etc., and centrally manage and control the system through the radio and television broadband network system.

2.1 Hardware

The functions, network working mode and structure of Hutone Model1608 data transmitter.

2.1.1 Function

Hutone Model1608 data transmission server is a full-featured eight-port RS232/422/485 device networking server with a 10M/100M adaptive Ethernet interface and supports Windows serial communication drivers, which means that using the RS-232 port on Hutone Model1608 is just like using the COM port on a PC. It also means that all software used on the original serial port device does not need to be modified, and TCP/IP Socket can be used to access serial data. The server can be used for data monitoring, acquisition, alarm, control room environment monitoring, and other purposes of radio and television transmitters.

2.1.2 COM Port Mode

Use the virtual serial port communication mode, in which one or more converters are connected to a computer to achieve two-way transparent data transmission. The virtual serial port software on the computer manages the converters below, and one virtual serial port can correspond to multiple converters, making it as convenient for the computer to manage serial port devices as managing its own serial ports.

2.1.3 Network working mode

In TCP/IP Server mode, the serial device server monitors the TCP/IP port and waits for connections. The device that initiates the connection to the serial device server can be a computer or other embedded network device.

In TCP/IP Client mode, the serial port server initiates a connection to the designated remote host TCP/IP port according to the settings. These hosts must work in Server mode.

UDP broadcast mode: In this mode, the serial port server will use UDP broadcast mode for data communication. This mode can realize the communication between a single virtual serial port and multiple serial port servers. It can also realize a one-to-many transparent transmission solution where one serial port server sends and multiple serial port servers receive.

2.1.4 Network Structure

Hutone Model1608 is used as a data transmission terminal, placed in the computer room, and connected to the central control computer through a broadband network. The central control computer can monitor and manage Hutone Model1608 and save the relevant data of the residents through the database.

2.2 Software

The network communication interface is responsible for processing the network transmission protocol. All protocol headers are removed from the data packets input from the network, and they are reassembled into complete application layer data in the buffer and sent to the intelligent control unit through the asynchronous communication port. The data sent from the transmitter monitoring system, environmental monitoring, access control system and other intelligent units are packaged in the communication interface unit and added with the protocol header to one or more hosts on the network. The media access protocol is Ethernet IEEE802.3, and the network transmission protocol uses TCP/IP or UDP/IP.

Application software includes transmitter monitoring software, environmental monitoring system software, etc. The transmitter monitoring software collects and stores the operating data of transmitter equipment through Hutone Model1608, displays data in various forms, generates data reports manually and automatically, alarms and automatically records abnormalities and faults, manages the logs of check-in personnel, stores data in the database, provides complete query and reporting functions, controls the transmitter power on and off, adjusts the operating parameters of the equipment, etc. The transmitter room environmental monitoring software monitors and controls the room's temperature, humidity, smoke, dust, power supply, etc.

3 System scalability and security

This system can be connected to the superior radio and television center via broadband to realize data reporting and aggregation. Security: TCP point-to-point connection is used between the device and the network management system, and the device does not receive any data packets from non-network management system IP addresses.

4 Conclusion

In order to meet the needs of radio and television room automation management, this system also has good interoperability and supports multiple communication media and network topologies. In the process of establishing and implementing the communication structure of the entire system, the principle of openness is fully considered, and nodes can be added or deleted at will, providing users with maximum flexibility.