Design Of Intelligent Transducer

With the development of Automation and the progress of the micro electronic technology, and the mature of Field Bus, digital control technology is widely used in production process, so collection, transition and treatment of signal should meet higher requirements. This thesis is about general development of field signal communication and status of intelligent transducer, analyzes function and operation principle of intelligent transducer. The transducer is designed chiefly for different weak output signal of non-standard sensors. It can amplify the weak signal, alter the amplification factor according to the size of the weak signal and improve system sensitivity. After sample data processed, it not only can output 4～20mA standard direct current, but also can communicate with other computers and single chip by mean of RS—485 bus. According to the output signal range of the sensor, the system sets the gain of amplification link which is composed of AD623 and X9241 by way of program, amplifies the weak signal to DC 0～5V, then makes A/D transition through multi—passages and 12 bit TLC2543, brings the sampled data to single chip 89C52, filtering the data, and transferring surveyor etc., then transits the data to 4～20mA DC signal by DAC0832, or sends the data to other computers through isolated RS—485 bus. The design of the system has its own separate watchdog and EEPROM memory circuit, therefore it can improve system reliability. Software of the system designs main program, amplifier gain setting program, ADC transition program, DAC transition program and processing subprogram by adopting assemble language of MCS—51 single chip and modularization program design method, and also designs corresponding communication protocol. The result is verified to attain the index requirements by debugging and practical operating, after system design has finished.