外文翻譯---基于plc和組態(tài)軟件的原油儲罐區(qū)監(jiān)督與控制系統(tǒng)-全文預(yù)覽
【正文】 soft redundant structure, when the control task switches to resereve CPU from the master one, Force Control should switch to the correct munication object to exchange datas. For this purpose, when device PLC is created in Force Control ,it should be configured properly and a data point should be defined in the realtime database as a redundancy switching flag. First configure I /O device for Force Control, create PLC whose equipment address is set to 2, if set to 1, Force Control will not be able to connect to the PLC. The standby channel is enabled and the device IP address and standby IP address should correspond with PLC’s two Ethernet munication modules CP3431. After I/O device PLC is created , define a data point in realtime database whose data type is selected as redundancy switching flag . The flag’s value is 0 in normal state, when its value is 1, Force Control will switch to PLC’s another IP address, then the value 1 will be cleared automatically. Here the data point is linked with MW16 of PLC. Corresponding program is loaded into PLC ,when the CPU is working as master station, MW16 is set to 0, when the CPU is working as reserve station, MW16 is set to 1, program in PLC is as follows: L L W162AWSRW 1T MW16B. Software of Superior Computer Force Control configuration software solves problems (1 )Creating a I/O device PLC (2 )Creating a realtime database and linking the data points with datas in PLC。 (4) Writing the program for valve control Fig. 4 Variable relation Fig. 4 shows the relationship among variables in Force Control, in PLC and in electric valves. Because there are a large number of valves to control in the system and the control methods are the same, a special function FC1 for valve control is written in order to simplify the structure of the program. is the flowchart of FC1. The valve has two control modes, local control mode and remote control mode. It is necessary to judge whether the valve is in the remote mode because only in this mode can the valve be controlled by the PLC. Valve opening process is as follows: click the mouse on openvalve button in Force Control’s graphical interface, the openvalve flag in PLC is set to 1 if mouse is down, then return to 0 if mouse returns up, PLC energizes the openvalve relay for 1 second according to the rising edge of openvalve flag,pares the actual valve opening with the preset value, once the former is equal to or greater than the latter, energizes the stop relay for 1 second immediately. Valve off process is similar with the above process. When the highlevel switch alarms, PLC drives the esd relay, then valve will open. 2009 3rd International Conference on Power Electronics Systems and Applications Digital Reference: K210509077 IV. CONCLUSION Superior puters in which Force Control configuration software are installed provide good humanmachine interface, municate with PLC through Industrial. Ethernet, then supervise and control the system. PLC perform reliable and effective control. Dual redundancy and software redundancy is adopted, improving the reliability of the system greatly. This system bines the advantages of puter and PLC, provides simple interface and high reliability, makes operation easy , and improves the automatic level of the oil depot. R EFERENCES [1] Liu Meijun. Siemens S7PLC Application and Maintenance, China Machine Press, 2008 [2] Beijing Sunway Force Control Technology ..Graphical interface and development system, Beijing,2007 [3] Siemens Ltd., China. Software Redundancy for SIMATIIC S7300 and S7400,Siemens Ltd., China, Industry Sector, Industry Aut
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