基于CTMU技术的超声波热量表设计

摘要

In the existing design proposal of ultrasonic heat meter,flow rate and temperature were measured by special integrated chip.Although it has superior performance,but the cost is high.This paper presented the design of an ultrasonic heat meter based on the PIC24FJ128GA310 as the main controller.Transit time principle was be used to measuring the flow rate in this meter.CTMU module was complete the accurate measurement of the time difference temperature measurement using signa-delta A/D method.The paper descirbed the CTMU module structure,the methods of use and precautions.The design greatly reduced the cost of the ultrasonic heat meter.Tests on the calibration table show that the designed products meet the design requirements stable.%现有超声波热量表方案大都采用专用集成芯片测量流量和温度,然后通过单片机计算得到热量.该方案使用简单方便,但是成本高.该设计以低功耗单片机PIC24FJ128GA310为主要控制器,流量采用时差法原理进行测量,使用CTMU模块完成时间差的精确测量;温度测量采用Signa-delta A/D方法.文中详细介绍了CTMU的结构、使用方法及测量校正方法,该方案大大降低了超声波热量表的成本,通过校验台测试,产品稳定,性能满足设计要求.