Research On Wireless Low-power Powder Material Moisture Meter

Low power consumption and wireless communication are the two big trends of instrument industry. Study on them has not only some more forward-looking meaning, but also some real application value.It is always a difficult problem to measure the moisture content of sinter mixture in sintering process. Investigating many of the existing field sintering moisture measurement methods, such as infrared method, the electrical conductivity metheod, the method of neutron method, and some comprehensive method, we can find that they are all without exception facing the same problem:measurement delay problem. With analysis of the traditional process, the biggest reason to the measurement delay problem is on that :while the sintering mixture mixing process is a long time, the traditional measuring method are mostly take measurment after the mixing process. Therefore, that long time for the sintering mixture mixing is the crux of the problem.From the perspective of soluting the measurement delay problem, a new measurement solution is creatively presented that set the instrument into the roller so as to eliminate the influence of the missing of moisture content during the mixing process, and then delay problem can be soluted.This paper focuses on the analysis of the measurement solution, building and testing of the moisture measuring platform. The main works are listed as fllows:(1)According to the innovative solution, demand analysis has been made in many points, such as the whole framework, the measurement principle, the power supply and communication. And low-power and wireless communication design requirements are presented.(2)According to the demand analysis, a lithium-battery power supply system is designed. At low power consumption demand and the actual situation, after contrast of many design methods, the paper has designed measurement circuit with the principle of electrical conductivity metheod, has designed multi-groups and multi-pairs of electrodes to make multi-measurement, also has designed square-stimulation circuit, controllable gained circuit, controllable zero adjustment circuit, V/F circuit and isolating circuit. In addtion, the main controlling and wireless communication circuit, MSP430F149 and CC1100 as the core, have also designed.(3)The software of signal detection, wireless communication, temperature measurement has designed.And the low power designed has been finished after the analysis of configureable statement of each module. In addition, the power consumption has been tested. (4)A measurement & control platform is built with a computer, SINK node and measurement notes. Besides, a linear evaluation system for the measurement circuit is built to improve the efficiency. Then, the fitting curves of the standard conductance are made.Results show that the platform built can work well, the conductance measurement accuracy:the relative error absolute value is less than0.7%, and on average, circuit cost 0.929mA-1.196mA in analog side and 0.905 mA-1.15mA (with the isolation shut down) in digital side.These have laid a good foundation for the following further measurement and modeling work.