| 摘要 |
<p>PURPOSE:To attain the same temperature control as the normal condition even at an abnormal condition by providing two temperature control systems having the same set temperature so as to switch one control system into the other of normal operation at a failure, in an incubator or an oven. CONSTITUTION:The temperature control systems A, B are provided, which comprise sensors 10A, 10B detecting temperature in a tank, temperature set devices 12A, 12B setting an objective temperature, error amplifiers 14A, 14B detecting the difference between both output levels of the sensors and the temperature set devices, pulse width modulation circuits 15A, 15B giving a pulse having a time width in response to the output difference of the amplifiers, and power control circuits 16A, 16B controlling the power application to heaters 17a, 17b. The operating state of the systems A, B is monitored, a microcomputer C judges it when a trouble takes place in either system, a relay X1 or X2 is operated, the system A or B is coupled to the heaters 17a, 17b, a buzzer is energized for the operator.</p> |
