Controller for ultrasonic sensors

An ultrasonic transducer for coupling to a two wire 4-20 mA communication loop, comprising:

• interface means for receiving power from the two wire communication loop and transmitting information related to transducer measurements over the two wire communication loop;
• an ultrasonic transducing element;
• means for periodically exciting the ultrasonic transducing element, obtaining a transducer measurement and providing the interface means with information related to a transducer measurement;
• and
• means, coupled to the interface means, for storing power received from the two wire communication loop and providing stored power to the means for periodically exciting.

An ultrasonic transducer for measuring a property of a material, comprising:

• an ultrasonic transducing element;
• means for exciting the ultrasonic transducing element;
• means for receiving a transducer output signal from the ultrasonic transducing element;
• means for decreasing strength of an excitation signal provided to the ultrasonic transducing element by the means for exciting;
• and
• comparator means for comparing strength of the transducer output signal with a threshold level and producing an output based upon the comparison which is related to a wet self-test.

An apparatus for controlling operation of ultrasonic transducers, comprising:

• a multiplexer adapted for coupling to a plurality of ultrasonic transducers and having a multiplexer output and a selection input for selecting which of the plurality of ultrasonic transducers is coupled to the multiplexer output;
• signal processing means for processing the multiplexer output based upon signal processing parameters received from a parameter input and providing a processed output;
• controller means for receiving an input related to a selected transducer, providing a signal to the selection input of the multiplexer whereby the selected transducer is coupled to the multiplexer output, and providing signal processing parameters related to the selected transducer to the signal processing means;
• interface means for receiving power from a two wire communication loop and transmitting the processed output over the two wire communication loop;
• means for periodically exciting the selected ultrasonic transducer;
• and
• means, coupled to the interface means, for storing power received from the two wire communication loop and providing stored power to the means for periodically exciting.

An apparatus for controlling operation of ultrasonic transducers, comprising:

• a multiplexer adapted for coupling to a plurality of ultrasonic transducers and having a multiplexer output and a selection input for selecting which of the plurality of ultrasonic transducers is coupled to the multiplexer output;
• signal processing means for processing the multiplexer output based upon signal processing parameters received from a parameter input and providing a processed output;
• controller means for receiving an input related to a selected transducer, providing a signal to the selection input of the multiplexer whereby the selected transducer is coupled to the multiplexer output, and providing signal processing parameters related to the selected transducer to the signal processing means;
• means for exciting a selected ultrasonic transducing element and obtaining a transducer output signal;
• wherein the controller means includes:
• means for decreasing strength of an excitation signal provided to the ultrasonic transducing element;
• and
• comparator means for comparing the strength of the transducer output signal with a reference signal level and producing an output based upon the comparison which is representative of a wet self-test.