便携式温度仪表校验仪

Design of Portable Temperature Calibrator

利用单片机技术设计便携式温度仪表校验仪,实现对电压、电流以及电阻的精确测量,根据二次仪表的不同模拟多种不同分度号的热电阻、热电偶输出电阻、mV以及电流信号。系统以单片机为核心,利用模数转换器和模拟开关构成多路测量电路,利用MAX539和AD421构成输出电路,实现测量和传感器以及智能仪表的校验。改变其软件的数据表可以实现对酸度计、电导仪等的校验。采用软件抗干扰措施,采样和输出数据可靠性高。系统输入输出硬件结构简单,具有电池充电电路,低成本,低功耗,具有较好的测量和输出精度。

In order to realize the accurate measurement of voltage,resistance or current signal,the portable temperature calibrator was designed by single-chip technology.Different thermal resistance,thermocouple with different sub-degree numbers were simulated according to different secondary instrument.The system took single-chip AT89C52 as the core,it can obtain the multi-channel measurement circuit by using A/D and analog switches.It can obtain the output-circuit by using MAX539 and AD421,in order to realize the measurement for the input signal and the calibration for sensor and intelligent instrument.The results indicate that it can achieve the calibration for acidometer and electric conductivity meter to increase or decrease the data sheet of software.It can realize better reliability by adopting measure of anti-jamming.This system has battery charging circuit,simple structure of hardware and low-power,low-cost,it has enough accuracy in practice.