The Functional Configuration Development Of Bus Node In Building Electrical Monitoring System

With the advance in computer, information and control technology and the continuous pursuit of highly efficient, comfortable and convenient living and working environment, intelligent building is emerged as required and developed rapidly. At the same time, building automation system is an important part of intelligent building, which is called building electrical monitoring system and used to implement monitoring for all electrical equipments of building. The transmission of monitoring information depends on the field bus technology. However, the functionality of the traditional field bus node is relatively simple, and the richness and diversity of the bus node’s content is relatively low. Based on the independently developed fieldbus technology, a function configurability design for the bus node of the building electrical monitoring system is implemented in this dissertation, thus improving the flexibility of the monitoring system.The general goals of the building electrical monitoring system is introduced through analyzing the custom developed field bus technology. According to the characteristics of the field bus, the framework of the building electrical monitoring system is built. The system includes three typical network topologies, where the bus nodes are connected by the field bus that is also connected to the bus gateway, and the bus gateway is used as a middle bridge and is connected to the monitoring server platform through the USB communication interface and supports Wi-Fi communication. For ease of implementation and application of the key communication protocol, the message package format suitable for this fieldbus communication is developed. Depending on function and usage, the messages are categorized into instruction message, inquiry message, feedback message and configuration message. The realization of the overall building electrical monitoring system and the communication protocol establishes a good foundation for the function configurability design of bus nodes.The functionality configuration of bus node refers to rewriting custom data to the storage area of the micro controller of bus node to make the bus node’s control from input to the output no longer fixed. In this dissertation, the configuration function of the bus node is firstly defined and divided into five classes, which include the node attribute, the power switch input, the sensor input, the state output and the jump instruction. The configuration data is stored in the E2PROM memory of the microprocessor. A tree structure is used as the data storage mode uses because the large amount of configuration data need to store in each node. Each of the configuration content is a branch of the tree, which includes various branches such as the triggering modes and the control targets. According to the bus message specification of communication protocol, the control message data of various objects is configured into the corresponding address of E2PROM memory so that different functions can be triggered and executed when inputs of some nodes change.Various test experiments are carried out for the function configurability of the bus node of the developed building electrical monitoring system, such as testing system hardware circuit and testing the accurate storage of various configuration data and testing execution of configuration function, etc. The results show that the hardware of the system is of stability and reliability, and the bus configuration message can be received or sent correctly. The function configurability design for the bus nodes is of rich operability, which promotes the flexibility of the monitoring system greatly.