| LNG(liquefied natural gas)is composed mainly of methane(CH4),is a high quality,clean,efficient,and convenient"green fuel",is considered the cleanest fossil Earth Energy. The development and utilization of liquefied natural gas are important for optimizing urban energy structure,promoting industrial production,improving the urban ecological environment and investment climate.Invest in the construction of LNG gasification station is on the rise and booming.In the construction projects of LNG gasification station, Automatic monitoring system is an important component of the station,rational design of the station control system,not only to ensure that the entire process at work,safe operation,but also to improve working condition,improve labor productivity.Supervisory Control and Acquisition is called SCADA for short,which is a system of the production process control and dispatching automation,is the techniques used for detecting on site and automation management.It can be used to monitor and control to the equipments on the site,so as to achieve data acquisition,equipments control,measuring and parameter adjustment as well as the regulations of a variety of signal alarm and so on.The system that established based on the techniques can be used for data acquisition on the site,then the data is sent to the controlling center through communication network,then the controlling center can do remote control to the equipments.SCADA system has been widely used in power,petrochemical,urban water supply,heating,gas and other industries.It can collect the data on the site in real-time,it can also achieve local and remote self-controlled,monitor the process of gas supply comprehensively and in real-time and provide necessary parameter basis for production,scheduling and management.This topic is from a gas company of Guangzhou cooperation projects,according to the control task and process requirement of LNG gasification station at the scene, puts forward the SCADA system control mode,which consists of dispatch center remote control,station control and local manual control.Thesis mainly describ the SCADA system software design of LNG gasification station in detail,including two parts of the station control system and dispatch control center software design.The system utilize upper and lower computer collaboration model,embedded controller as the core of the lower computer control system,is responsible for collecting data and control industr site;VB6.0 as monitor software development tools, through configutating a series typical interface,the design variables to process the data and archiving,alarm monitori: and archiving,remote operation of electric ball valves and so on,the gasification stati site layout,production data and alarm information directly display to the user,gasificati station is equipped with GPRS module, real-time production data will be reported to t city natural gas control center through the GPRS network, concentrated schedulii supervision. MCU MC9S12 which is the latest product of Motorola company has be adopted as key calculate part of the controller,in the structure of the software,t embedded real-time operating system uC/OS-â…¡have been used,which makes the syste work as a real time system and can be designed simply.Except expected developed system in keeping original system functi well-found,stable and reliable performance characteristics, and will improved greatly flexibility and reduced production cost of the whole control system,provided a stroi support for inputs and use for follow-up.Because writing requires,this article on discussed the system software design and implementation. |
