hysteresiscontroller.java

这是一个以JAVA编写的程序,本人还没有试过,是一个简单的温度控制系统

package net.sf.dz.controller;

import org.freehold.jukebox.logger.LogChannel;

/**
 * A hysteresis controller.
 *
 * <p>
 *
 * The controller output becomes positive when the process variable becomes
 * higher than the setpoint plus hysteresis, and it becomes negative when
 * the process variable becomes lower than the setpoint minus hysteresis.
 *
 * @author Copyright &copy; <a href="mailto:[e-mail]"> Vadim Tkachenko</a> 2001
 * @version $Id: HysteresisController.java,v 1.5 2004/06/28 20:35:46 vtt Exp $
 */
public class HysteresisController extends AbstractProcessController {

    /**
     * Log channel to use.
     */
    public static final LogChannel CH_HYSTERESIS = new LogChannel("Hysteresis");

    /**
     * The process variable hysteresis.
     */
    private double hysteresis;

    /**
     * The controller state.
     *
     * Initial state is off.
     */
    private boolean state = false;

    /**
     * This constructor has to exist so the instance can be created via
     * <code>Class.newInstance()</code>.
     */
    public HysteresisController() {

    }

    /**
     * Read the hysteresis value from the configuration.
     *
     * @exception Throwable if there's a problem with configuration.
     */
    protected final void configure2() throws Throwable {

        // VT: NOTE: Hysteresis of +-1 seems to be a reasonable default

        hysteresis = getConfiguration().getDouble(getConfigurationRoot() + ".hysteresis", 1.0);

        complain(LOG_DEBUG, CH_HYSTERESIS, "Hysteresis: " + hysteresis);
    }

    /**
     * {@inheritDoc}
     */
    public final synchronized double compute() {

        double pv = getProcessVariable();
        double setpoint = getSetpoint();

        if (state) {

            if (pv + hysteresis < setpoint) {

                state = false;
            }

        } else {

            if (pv - hysteresis > setpoint) {

                state = true;
            }
        }

        return state ? 1 : -1;
    }

    /**
     * {@inheritDoc}
     */
    protected final boolean needsDataSet() {

        return false;
    }
}