一种高精度多路温度采集方法研究

惯性平台系统是一种框架系统,主要包括平台本体、电路箱和电源箱.平台系统精度主要靠安装在平台本体的三浮陀螺和加速度计来保证.通常惯性平台的工作环境比较严酷,惯性传感器对温度有很高的敏感度,在系统正常工作时,平台内部有二级温控来保证仪表有良好的工作环境,但内部空间温度梯度变化会影响惯性传感器的精度.在温度采集过程中,铂电阻存在非线性、自热效应及热电动势等电气干扰的精度影响.采用阻值比较法,通过引入恒定激励电流来抑制温度采集电路的自热效应,并基于FPGA设计并行多通道温度采集电路.给出了系统总体设计方案、测温电路参数设计、序列激励电流控制和数字滤波补偿的具体实现方式,测试结果表明该系统可实现64路温度采集,在一定范围内测温精度能达到±0.02℃,满足精度要求.

Research on the Multiple-channel Temperature Sampling Method

Inertial platform system is a framework system which consists of platform, circuit box and power box. The precision of platform system is influenced by inertial meters on platform body. Because of the temperature sensitivity about inertial meters, two zones of temperature control system is designed to ensure a fine working environment for the instrument, but temperature gradient of the platform internal space changes will affect the precision of system. The precision is affected by the nonlinear of platinum resistance, self-heating and thermoelectric interference. The method of resistance value comparison and constant excitation current is employed in this paper to overcoming the self-heating effect. Furthermore, the design of parallel acquisition for the multi-channel temperature was based on FPGA. This paper provides the system design methods for the temperature measurement through the realization of sequence current, compensation and digital filter. The testing results show that the 64 channels of temperature acquisition fulfills the accuracy requirements in a certain range can be realized