three position

This article introduces a practical water supply system with frequency convertor which is based on three state controller, and introduces in particular how to apply PLC to produce speed-rising curve of frequency converter.

本文介绍一种实用的基于三位式调节器的变频调速供水系统。

The paper analyses the principle of nonlinear control for indoor corstant temperature system with three position relay,and shows a wide application of nonlinear control method in air-condition system.

分析三位式继电器非线性控制的室内恒温系统工作原理，并指出非线性控制在空调系统中的广泛应用。