范围为0-99的双向定时器，当系统为正定时器时，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99，即从99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 0-99 timer, the timer when the system is positive, 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 corresponding control signals to control other equipment, when the request timer was used as the initial time to 99, down from 99 by the beginning of time, when the reduced time settings, the timer would stop working, the system output corresponding control signal.