| 摘要 |
<p>PURPOSE:To quicken a rise time of a molten metal temperature, and also to suppress a variation of the molten metal temperature to the minimum by providing a gain switching circuit, making the gain large when a signal of a molten metal temperature sensor is below a set temperature, and making the gain small when said temperature is above the set temperature. CONSTITUTION:A gain switching circuit 10 compares a signal which has been voltage-divided by a combined resistance of a resistance 8 and a resistance 9 and 4, namely, a set temperature T2 signal which is lower by some temperature than a set temperature T1, and a molten metal temperature signal which has been voltage-divided by a resistance 2 and a molten metal temperature sensor 5, and makes the gain of a proportion controlling circuit 6 large by providing an output to the proportion controlling circuit, if the molten metal temperature is lower than the set temperature T2, therefore, a rise time of the molten metal temperature is quickened. Also, at the time point when the molten metal temperature has become higher than the temperature T1, a signal is not outputted from the gain switching circuit 10, therefore, the gain of the proportion controlling circuit 6 becomes small, and a variation of the molten metal temperature in the vicinity of the set temperature can be suppressed to the minimum.</p> |
