Piezoelectric measuring device and method of operating the measuring device

A piezoelectric measuring device, comprising:

• a sensor element configured to generate and transmit a measurement signal for a pressure to be measured and including an operational amplifier, which includes an inverting input and an output;
• a data acquisition device configured to acquire and evaluate a transmitted measurement signal;
• a conductor element configured and disposed for transmitting the measurement signal between the sensor element and the data acquisition device;
• wherein the sensor element includes a feedback capacitance that is arranged electrically in parallel with the inverting input and the output of the operational amplifier;
• wherein the sensor element includes a reset switching element arranged electrically in parallel with the inverting input and the output of the operational amplifier;
• wherein the data acquisition device is additionally configured to provide an electrical supply voltage for the sensor element and includes a measuring cycle circuit and a power-on reset logic;
• wherein the measuring cycle circuit is configured to switch on the electrical supply voltage for the sensor element prior to the start of a measuring cycle and to switch off the electrical supply voltage after completion of the measuring cycle;
• and wherein the power-on reset logic is configured to detect the presence of the electrical supply voltage and, wherein the power-on reset logic is configured to close the reset switching element if the electrical supply voltage is present prior to the start of a measurement cycle and to reopen the reset switching element if the electrical supply voltage is not detected;
• wherein the power-on reset logic is configured to actuate the reset switching element to discharge the feedback capacitance;
• and
• wherein the reset switching element comprises a power-on reset logic that is configured and disposed to close the reset switching element for discharging the feedback capacitance after a predetermined voltage value has been exceeded for a defined time and open the reset switching element when the predetermined voltage value no longer is exceeded for the defined time.

A method for operating a piezoelectric measuring device during a measurement cycle according to the following steps:

• generating from a sensor element, a measurement signal indicative of a pressure to be measured;
• transmitting the measurement signal by means of a conductor element to a data acquisition device that detects and evaluates the transmitted measurement signal;
• wherein the data acquisition device comprises a tare circuit that tares a first measurement signal transmitted from the sensor element to the data acquisition device;
• wherein the sensor element comprises an operational amplifier having an inverting input and an output;
• wherein the sensor element comprises a feedback capacitance electrically arranged in parallel with the inverting input and the output of the operational amplifier;
• wherein the sensor element comprises a reset switching element arranged in parallel with the inverting input and the output of the operational amplifier;
• wherein the data acquisition device additionally provides an electrical supply voltage for the sensor element and comprises a measurement cycle circuit;
• switching on the electrical supply voltage for the sensor element prior to the start of the measurement cycle;
• wherein the sensor element comprises a power-on reset logic;
• wherein the power-on reset logic detects the presence of the electrical supply voltage and, if the electrical supply voltage is present, then the power-on reset logic closes and reopens the reset switching element prior to the start of the measurement cycle;
• and
• the measuring cycle circuit switches off the electrical supply voltage for the sensor element after completion of the measurement cycle.

A method for operating a piezoelectric measuring device according to the following steps:

• generating from a sensor element, a measurement signal indicative of a pressure to be measured;
• transmitting the measurement signal by means of a conductor element to a data acquisition device that detects and evaluates the transmitted measurement signal;
• wherein the sensor element comprises an operational amplifier having an inverting input and an output;
• wherein the sensor element comprises a feedback capacitance electrically arranged in parallel with the inverting input and the output of the operational amplifier;
• wherein the sensor element comprises a reset switching element arranged in parallel with the inverting input and the output of the operational amplifier;
• wherein the data acquisition device additionally provides an electrical supply voltage for the sensor element and comprises a measurement cycle circuit;
• switching on the electrical supply voltage for the sensor element prior to the start of a measurement cycle;
• wherein the sensor element comprises a power-on reset logic;
• wherein the power-on reset logic detects the presence of the electrical supply voltage and, if the electrical supply voltage is present, then the power-on reset logic closes and reopens the reset switching element prior to the start of a measurement cycle;
• wherein the measuring cycle circuit switches off the electrical supply voltage for the sensor element after completion of the measuring cycle;
• wherein the power-on reset logic actuates the reset switching element to discharge the feedback capacitance;
• and
• wherein the reset switching element comprises a power-on reset logic that closes the reset switching element for discharging the feedback capacitance after a predetermined voltage value has been exceeded for a defined time and opens the reset switching element when the predetermined voltage value no longer is exceeded for the defined time.