某系统用的罐体设备在生产中需采用多种、多段预先设置的温度曲线(包括多次升温、保温、冷却降温)控制,准备采用欧陆(EUROTHERM)818系列的智能仪表控制。该表具有冷、热两路控制输出和报警功能,热输出为时间比例输出,控制晶闸管的通断时间来控制加热;冷输出为4～20mA输出,用以控制主、预冷调节阀的开度,从而控制降温水的水量,达到控制降温速率的目 The tank equipment used in a system needs to be controlled by a variety of preset temperature curves (including multiple heating, holding and cooling) in production to be controlled by EUROTHERM 818 series smart meters. The table has cold and hot two-way control output and alarm function, the heat output is the time proportional output, control the thyristor on-off time to control the heating; cold output is 4 ~ 20mA output to control the main, precooling control valve open Degrees, thereby controlling the amount of water cooling water to achieve the purpose of controlling the cooling rate