范围为0-9999的双向定时器，当我们要求系统为正定时器时，初始时间为00，即从00开始向上加计时，当加计时到设定值，正定时器停止工作，系统输出相应的控制信号，控制其他设备，当要求作为倒定时器使用时，初始时间为9999，即从9999开始向下减计时，当减到计时设定值时，倒定时器停止工作，系统输出相应的控制信号。-Two-way range of 0-9999 timer, when we ask the system timer is, the initial 00 hours, that is, upward increase from 00 the beginning of time, when the increase in time to set the value of the timer is to stop working, the system output the corresponding control signals to control other equipment, when the request timer was used as the initial time for 9999, down from 9999 by the beginning of time, when the reduced time settings, the timer would stop working, the system output the corresponding control signal.