An Auto Feed-back Control Solid Flow-meter Based On Impulse Theory

On chemical and construction industry, powder and granule material measure is always necessary. Research and design of solid material flow measure and control system is still not quite mature, system integration and measure precision require improvements. Impulse solid flow-meter is used as flow measure equipment. Based on collection of various material, sum up of former experience, use for reference on others' valuable thought, we discussed optimize methods of impulses solid flow meter: optimizing sensor select and circuit design to improve precision, integrating auto-control function to simplify system construction; analyzed design methods about real-time, reliability and maintainability; designed flow sample subsystem, data process subsystem, flow control subsystem, communication interfaces and power circuits; transplantedμClinux operation system on flow-meter, developed hardware devices' driver; designed parameters verifying and testing methods of flow-meter.The sample subsystem of flow-meter made up of HR100, a high accuracy LVDT sensor, AD598, a precise signal conditioner, and TLC2543, a 12-bit switch capacitance A-D converter, ensured measure precision through high accuracy peripheral components and optimized circuits, reduced interrupt effects through optoisolator adoption and reasonable arrangements; adopted stepping motor as control component, integrated flow control function into flow-meter, simplified system construction. Besides, data process subsystem was totally isolated by optoisolators to prevent system from EMI, which may cause frequent restarting or accidental halt; robust design was considered on circuit and PCB design process.The flow meter has been operated in certain great feedstuff processing enterprise of Linyi, Shan Dong province for 3 months, comparing with certain imported advanced equipment. The flow-meter has an accumulating error of less than 1 percent, which is correspond to the imported equipment, and with a cost of 1/20. The flow-meter is well reflected by consumer, and it is on batch production recently.