PLC对输入模拟量的一种处理方法

Sort of Means for Dealing with Input Analog Signals in PLC

针对小型机或整体机PLC无法处理模拟量的问题,提出应用双斜式A/D转换器的原理,利用常用的器件组建A/D转换器,再利用PLC的内部的计数功能,将模拟量转换成时间量,在原有的不能处理模拟量的可编程控制器上,实现用很少的输入点数完成模拟量的处理,提高了系统的性价比。已将此方法成功地应用于电弧炉控制系统中。

Contraposing the problem that small-PLC or unitary PLC can＇ t deal with input analog signals, the principle of double-tilted line ADC was brought forward, ADC is built with the familiar elements and the inner counter in PLC was applied. Thus the analog signals can be transformed into time signals, the PLC that can＇t deal with input analog signals formerly can achieve analog signals disposal only by few input spots. Capability price ratio was improved. The method has been used in the control system for electrode arc furnace.