Design Of Networked Smart Sensor RTU In Monitor & Control System Of Tunnel

The project "Power Supply's Remote Monitor & Control System in Expressway Tunnel" (2005D104) is funded by the Science & Technology Bureau of Fujian province. As part of this project, the paper made systemic research on expressway tunnel monitor, accomplished the design and the primary application of networked smart sensor (NSS).The architecture of system based on the requirement was established, and CAN-Bus was selected to construct field net connecting NSSes among many communication ways. Protocol was also introduced. Further, a universal model of smart sensors was extracted after considering many inspecting points and parameters in tunnel monitor system. Based on what we concluded, we designed a Universal Smart Sensor Terminal (USST) with PIC18F4580 which is not only to acquire those parameters such as illumination, carbon monoxide, visibility, but also to function as controller of fans and illuminations, etc. The Sofware Configure Technology (SCT) was intrduced to develop MCU's software which plays a unique and important role in NSS.Besides these, Special Smart Sensor and Terminals (SSST) were developed to acquire those that USST cannot do, such as AC Parameter, Battery, Man-machine Interaction (MMI) etc. The SSST of AC Parameter could measure the AC's parameter, such as voltage, current, frequency etc. The "Zero Trigger Measure" has been introduced in the SSST of Battery, which made high-precision online monitor come true. This RTU provide the parameters, such as voltage, temperature, charge-discharge current, status of battery. The SSST of MMI adopted LCD with touch screen, which provided a better MMI. The paper also analyzed the interference source of tunnel monitor spot in detail, and took effective measures both in hardware and software to enhance the reliability of the system.We did research in the MCU software design of NSS. C language and self-determination control mode are platformed to build the software architecture. By analysising the structure and characteristic of dead-lock in MCU software system, we introduced a method to catch dead-lock and to handle it, which only costs a few RAM and one timer.