| 摘要 |
PURPOSE:To make it convenient to use a water heater, by preventing danger caused by extremely hot water and by indicating the cause why the temperature in water is lower than a desired temperature, by determining the controlled rate by the deviation of an output temperature from a target temperature by PID operation, and by displaying that the limit of controlled capacity is exceeded by detecting the saturation of an integral action. CONSTITUTION:A deviated output on one arm of a bridge circuit 21 containing a temperature setter 14 and a thermistor 12 on the circuit is via a buffer amp. 22, and another deviated output is driectly, put into a proportional and integral circuit 23 and a differential circuit 24, respectively. When hot-water is put out exceeding the limit of controlled capacity, the condition of imaginary shortening is lost in an operational amplifier 231, and deviation is caused on the voltage which is put into a differential amplifier 28 or 29. Then the output voltage from the differential amplifiers 28 and 29 becomes higher than the reference voltage being set by comparators 30 and 31, and a photo diode 32 or 33 in either one of the comparators 30 or 31, in which an output level becomes higher, is actuated to turn ON a light. |
