摘要
工控现场常遇到对温度的监控,而对温度数据的采集和控制是解决问题的关键。通常工控现场使用PLC(可编程序控制器)作为系统的控制核心,温度变量经温度传感器(热电偶或热电阻)采集后,送入PLC的特殊功能单元——温度模块(变送器+模数转换),温度模块对采集到的温度模拟量数据(电压或电流)自动进行模数(A/D)变换,最后转变为PLC可读的数字量(16进制数,以二进制数存放),通过对PLC编程可实现对读入的温度数据进行单位转换和数模(D/A)转换,根据工业现场需要,编制相应的PLC处理程序,可对温度进行开环或闭环控制及实现温度对其他设备的跟随控制。
The monitoring and control of temperature in industrial control field is often met. The collecting and control of temperature data is the key to solve problems. Usually, PLC is a system＇s control core and temperature variable collected via temperature sensors（thermocouples or thermal resistors）can be sent to the special function unit of a PLC, namely, temperature module （converting apparatus plus anologdigidal conversion）. Temperature module converts the detected temperature anolog data （voltage or current） into digital data automatically（which can be read by a PLC finally）. A PLC can process the units of the temperature data and convert the digital data into corresponding voltage or current by internal program. One can design certain PLC program with the need of the industry field to control the temperature in open - loop or close - loop and control other facilities by using of the converted temperature data from time to time.
出处
《现代电子技术》
2008年第17期177-179,共3页
Modern Electronics Technique
关键词
快闪存储器
热电偶
热电阻
变送器
模数转换
flash memory
thermocouple
thermal resistor
converting apparatus
anolog digital conversion
