The Ventilation Supervision And Control System Of Highway Tunnel

Along with the rapid development of freeway in our country, the investment and scale of tunnel construction is getting bigger and bigger. Meanwhile, the ventilation and monitoring system become increasingly intelligent and systematic. Well-functioning ventilation and monitoring system could guarantee the drivers' safety, and contribute a lot to the later extension of the apparatus. This paper focuses on the hardware selection of the ventilation system, the control algorithm, network distribution and communication; moreover, the software and hardware implementation of lower computer, the human-machine interface of host computer and the database are proposed deeply. The work includes:(1) Contrast and compare between the ventilation solutions in tunnel ventilation system, provide different solutions due to respective conditions.(2) In this Paper the feasibility and advantages of Field bus in the ventilation and monitoring system are presented, particularly the advantages of PROFIBUS-DP are discussed, and the detailed implementation of the overall network of the system and its framework are provided.(3) The S7-200 PLC of Siemens Corporation is selected as the main component of the control section; it is connected to the PROFIBUS-DP network as the client node using specific module.(4) The feed forward control algorithm is used and modified; thereon of power-saving with the operation characteristic curve of the ventilation tunnel and fans is analyzed. The transducer is used in the system so as to avoid negative effects to other electrical equipment by directly switching on the fan, and to save energy effectively.(5) In this case the human-machine interface is developed by Delphi, and the control configuration and parameter settings are displayed in a direct fashion, making it easier and friendly for access to data and control. The SQL Server 2000 database is also integrated in the system to store traffic flow, CO/VI history data in order to study and analyze.(6) In this system the real-time communication between PLCs, PLC and host computer, PLC and transducer, human-machine interface and database, and the overall system are implemented successfully, so that the control system would be safe and robust.(7) By adopting thereon mentioned design the whole system has a characteristic of expansibility, and can be easily altered according to certain circumstance with great flexibility.