Digital control instrument for measuring liquid level of boiler

The utility model relates to a digital type control instrument for measuring liquid level in boilers, which is composed of a liquid level sensor 1, a liquid level comparator 2, an A/D converter, a digital display 4 and a liquid level alarm regulator. The liquid level sensor is composed of an oscillator 10, a frequency voltage converter 11 and a subtracter 12, the oscillator is composed of a C< X >, an R< 1 >, an R< 2 > and an IC< 1 >, and the C< X > are fixed in the boiler by two mutual parallel metal plates and is connected with a resonance return circuit via a conduit. The utility model cancels the water connection pipe or the air connection pipe of a water level gauge and the boiler and accomplishes the electric integration of liquid level measuring, displaying and controlling. Therefore, the utility model can enhance reliability and increase reading precision and controlling precision, the liquid level can be randomly defined so as to accomplish computer networking.