基于两级闭环控制的型砂水分在线测控系统

Measuring and Controlling System of Moisture Ratio in Molding Sand Based on Two Level Closed Loop Control

提出了一种基于两级闭环控制的新型型砂水分控制系统,阐述了温度补偿系数的设定方法。该系统以单片机为控制核心,通过检测旧砂温度和含水量控制砂冷却系统的加水量,以实现旧砂含水量的初步控制;通过测量检测冷却后的旧砂含水量,控制混砂机的加水量。系统采用了自行研制的水分传感器实现型砂水分的在线检测,选用了美国Dal-las公司最新推出的DS18B20数字式温度传感器检测砂温及环境温度,以实现系统的温度补偿。本系统具有运行可靠,灵敏度高,控制精度高等特点。

A new Measuring and controlling system of moistttre ratio in molding sand based on two level dosed loop control is presented, and setting method of temperature compensation factor is described. The system is controlled by single-chip, the amount of water supply of the sand cooler is controlled by measuring temperature and moistttre ratio of the sand being reclaimed from the mold releasing after pouring so that the moisture ratio of reclaimed sand is controled roughly, and the amount of water supply of the sand mixer is controled by measuring the moisture ratio of cooled reclaimed sand. The moisture ratio in molding sand is measured by the moisture sensor designed by us, and sand temperature and atmospheric temperature is treasured by DS18B20 digital temperature sensor produced by America Dallas in order to realize temperature compensation of the system. The system has the characteristics of high reliability, high sensitivity, high control precision.