OIL Tank Data Acquisition And Control System Based On Modbus Fieldbus

In oil stock of army the measurement burden is heavy and the method is under-developed at present time. To resolve this problem and carry out the automatic management, the POL Research Institute of General Logistics Department developed the automatic oil tank data acquisition and control system based on Modbus fieldbus and put it to use. The author takes part in the research group and is responsible for the part of the hardware and software design of the data processing unit and software of PC.The automatic oil tank data acquisition and control system based on MODBUS fieldbus consists of fieldbus devices of oil tank, Modbus network and computers. It can be used in the oil stock of army and petroleum and chemical plant. Modbus transducer is the key device in the system and is used to offer power supply of pressure and temperature sensor, to collect signal, to linearizate and compensate temperature ,to calculate density , volume and mass , to transmit data to Modbus network , and display the data.So the Modbus transducer is a multi-parament measurement, intelligent control device which can manage multi-signal. Modbus fieldbus can monitor and manage automaticly the oil tank area by connecting the sensor and pc.The pc of installing HMI software take charge to monitor the data and to communicate the data to information network.At the beginning of this thesis the fieldbus technology application of the measurement and control system and MODBUS and any information of oil tank measurement and control system at present and future are presented. The gauging system's structure, function and characteristic following the principle and method of tank gauging are described. Then the Modbus sensor structure is described, introduces detailedly the hardtware design and the software design the data processing unit and software of PC by VB, bring forward the methors of analog ouput controlling, the author summarized some method of resolving the problems which were noticed at the process of debugging Finally, the author analysised simply the errors of measurment.