Research on Intelligent Network UPS Power Supply Monitoring Technology

UPS (Uninterruptible Power System) is a computer power protection device with an inverter as its main component and a stable voltage and frequency output. UPS appeared along with the birth of computers. In particular, the rapid development of microcomputers has objectively promoted the development of UPS power supplies [1]. The basic function of UPS is to take over the mains power supply and continuously supply power when there is a power outage. Due to the fast response speed of electronic components, power can be continuously supplied within 4-8ms at the moment of power outage, solving the existing power outage, low voltage, high voltage, surge, noise and other phenomena, making our computer system and network operation more stable and safe.

With the development of computer technology, computers and their networks have put forward higher requirements for corresponding power security. Under such a premise, intelligent network UPS power supply came into being. Intelligent network UPS power supply system mainly takes the network as the management object, adds RS232, 485 interface El, SNMP (Simple Network Management Protocol) card and other types of communication interfaces at the output end of the UPS host, uses the interface to connect with the corresponding communication interface on the server, router, gateway and other devices through a dedicated communication cable, and forms an intelligent network power supply system with monitoring function with the UPS power supply and the computer network. At present, there are two main aspects of UPS network intelligent technology: one is to coordinate with the software on the server, so that the UPS can not only complete the uninterrupted power supply, but also realize network fault alarm, event, data log recording, UPS parameter automatic test analysis, adjustment function, etc.; the second is to connect the traditional UPS to the computer through the hardware interface, combined with specially designed software, to provide a complete power management solution to enhance the UPS energy-saving function.

There are three main types of UPS monitoring technologies[2]: (1) monitoring technology based on serial communication; (2) monitoring technology based on Web; and (3) monitoring technology based on SNMP.

Monitoring technology based on serial communication is limited by the communication distance and is mainly used for monitoring UPS in the local area network. Web-based monitoring technology connects UPS to a host, monitors UPS distributed in the WAN through the Web browser on the host, and regularly generates UPS status reports (including UPS status and battery status) and converts them into certain format files to facilitate UPS management, diagnosis, and event processing, ensuring the safe shutdown of the computer system when power or UPS fails, keeping UPS in a healthy operating state, and improving the availability of the computer network when power fails. Its convenience lies in the fact that no modification is required to the existing power supply system. However, the communication monitoring software is installed on the system host through the host Internet access, and it needs to occupy a large amount of host resources when it works. If the amount of information of the UPS is large, it will inevitably affect the stable operation and performance of the host. Monitoring technology based on SNMP is mainly used in enterprise-level networks with a large number of UPS and wide distribution. Equip the UPS with a network card or directly integrate the SNMP adapter into the UPS, control and diagnose the UPS as an independent node in the network, access your own computer and website through the network, or access the monitoring system through the serial port and the network to remotely monitor the power system or shut down the network, provide real-time status analysis of the UPS's current, voltage, battery backup time and load, and notify the user in time when a fault occurs, so that the system administrator can quickly and easily determine where the power failure occurs and quickly solve it, so as to minimize the impact on network performance, and can time the UPS and system to realize UPS self-test, etc. This type of UPS system is sensitive, highly controllable, and has a wide range of applications. The following mainly discusses the intelligent network UPS system based on SN-MP monitoring technology.

The hardware part of a complete intelligent network UPS system should at least include the rectifier filter part, the inverter part, the battery system and other auxiliary parts. The coordination of each part can form a good UPS operating environment. Its system structure is shown in Figure 1. The system is connected to the UPS adapter through the R8232 power generation circuit, and the UPS adapter replaces the corresponding computer as a node of the network to access the network. That is to say, each UPS has its own unique address. Other users and network administrators on the network can see any information of the UPS by entering the IP address. The administrator can use any computer in the network to monitor the corresponding UPS. In special cases, the software can notify the maintenance personnel to respond accordingly through paging, E-mail, etc. When the UPS encounters special situations, the basic situation of the UPS can also be observed from any computer in the network and effective measures can be implemented. Its basic design principle is shown in Figure 2.

Highly intelligent UPS monitoring technology requires not only the support of hardware systems, but also the support of corresponding power monitoring software and SNMP manager. Users can perform remote monitoring and data network communication operations between UPS and network platform, so that UPS has remote management capabilities and becomes an important part of network system. The software part of intelligent UPS monitoring system mainly consists of three parts: intelligent network UPS communication display module, communication part with computer and watchdog circuit.

The main function of the communication display module is to display various information during the use of the UPS on the LCD screen on the control panel. The main hardware connection method is to use a single-chip microcomputer (such as AT89C51) to connect to the LCD screen in an analog interface manner; the power button is directly connected to the INTO of 89C51 to implement the system's power on and off function in an interrupt manner, and a corresponding menu structure is designed to simplify the operation.

The communication part is mainly responsible for the communication between UPS and computer, and generally adopts dual-channel driver/receiver Max232 to realize the corresponding functions. In the software design, its interface program is mainly composed of sending subroutine and communication port interrupt processing receiving subroutine. When sending, first send a start bit (low level), then send 8 bits of data in the order of low bit first, and finally send the stop bit. When receiving, first determine whether the RXU receiving port has a starting low level. If so, receive 8 bits in the order of low bit first, and finally determine whether RXD has a high level. If so, complete a data reception, otherwise continue to wait. The program flow chart is shown in the figure below. Figure 3 is the flow chart of the sending process, and Figure 4 is the flow chart of the receiving process.

Conclusion: The close integration of UPS system and Internet technology makes UPS system easier to use and safer than ever before. With the widespread and globalization of the network, users will have higher and higher requirements for network availability, which will extend UPS from protecting key network equipment to protecting the entire network path, which also puts forward higher requirements for the further development of UPS power supply.