Abstract: A system and method detect the presence of an unacceptable quantity of gas molecules in the reference vacuum cavity of a capacitance diaphragm gauge (CDG). An independent pressure transducer has an active portion exposed to the reference vacuum cavity. The transducer includes a ring anode, a cylindrical inner wall surface that forms at least one cathode, and a magnet positioned with respect to the ring anode such that the magnetic flux of the magnet is generally aligned with the central axis of the ring anode. A high voltage source applies a voltage between the ring anode and the cathode. A current sensor senses a magnitude of any current flowing between the ring anode and the cathode via ionized gas molecules. A monitoring unit monitors the magnitude of the current sensed by the current sensor and activates an alarm when the magnitude of the current exceeds an acceptable magnitude.

Abstract: A system and a method detect contamination of a diaphragm in a capacitance diaphragm gauge wherein a contaminated diaphragm deflects less in the presence of pressure than an uncontaminated diaphragm. The system and method measure a base pressure. A DC voltage is applied between the diaphragm and a fixed electrode to cause the diaphragm to deflect to simulate an effective pressure. The system and method measure a combined pressure caused by the base pressure and the effective pressure. The system and method subtract the base pressure to determine the effective pressure caused by the static diaphragm deflection. If the measured effective pressure is less than an acceptable effective pressure, the system and method determine that the diaphragm is contaminated.

Abstract: A system and method compensate for effects of gravity on the diaphragm of a capacitance diaphragm gauge (CDG). The CDG generates a measured absolute pressure value in response to an applied absolute pressure on an input of the CDG. The CDG is subjected to a variable orientation of the CDG with respect to the earth's surface that can cause inaccurate pressure measurements. A pressure measuring circuit generates a measured value of an applied absolute pressure provided to an input of the CDG. A tilt sensor generates at least one tilt sensor output value that is responsive to an orientation of the CDG with respect to the earth's surface. A processing system adjusts the measured absolute pressure value by a calibration factor to generate a calibrated absolute pressure value representing the applied absolute pressure, wherein the calibration factor is selected in response to the at least one tilt sensor output value.

Abstract: A system and a method detect contamination of a diaphragm in a capacitance diaphragm gauge wherein a contaminated diaphragm deflects less in the presence of pressure than an uncontaminated diaphragm. The system and method measure a base pressure. A DC voltage is applied between the diaphragm and a fixed electrode to cause the diaphragm to deflect to simulate an effective pressure. The system and method measure a combined pressure caused by the base pressure and the effective pressure. The system and method subtract the base pressure to determine the effective pressure caused by the static diaphragm deflection. If the measured effective pressure is less than an acceptable effective pressure, the system and method determine that the diaphragm is contaminated.

Abstract: A system and method detect the presence of an unacceptable quantity of gas molecules in the reference vacuum cavity of a capacitance diaphragm gauge (CDG). An independent pressure transducer has an active portion exposed to the reference vacuum cavity. The transducer includes a ring anode, a cylindrical inner wall surface that forms at least one cathode, and a magnet positioned with respect to the ring anode such that the magnetic flux of the magnet is generally aligned with the central axis of the ring anode. A high voltage source applies a voltage between the ring anode and the cathode. A current sensor senses a magnitude of any current flowing between the ring anode and the cathode via ionized gas molecules. A monitoring unit monitors the magnitude of the current sensed by the current sensor and activates an alarm when the magnitude of the current exceeds an acceptable magnitude.

Abstract: In order to mitigate the negative effects of a change in atmospheric pressure, an improved capacitance diaphragm gauge (CDG) sensor incorporates an independent ambient atmospheric pressure sensor near the CDG sensor body. The ambient atmospheric sensor is located outside the CDG sensor body to sense the ambient atmospheric pressure surrounding the CDG sensor body. The ambient atmospheric sensor provides an output that represents the ambient atmospheric pressure. A sensor output processing circuit receives the output of the ambient atmospheric sensor as well as the output of the CDG sensor. The processing circuit utilizes the output from the ambient atmospheric pressure sensor to fine tune the CDG measurement of pressure by executing an in situ, real time, automatic calibration adjustment of the CDG.

Abstract: A system and method detect the presence of an unacceptable quantity of gas molecules in the reference vacuum cavity of a capacitance diaphragm gauge (CDG). An independent pressure transducer has an active portion exposed to the reference vacuum cavity. The transducer includes a ring anode, a cylindrical inner wall surface that forms at least one cathode, and a magnet positioned with respect to the ring anode such that the magnetic flux of the magnet is generally aligned with the central axis of the ring anode. A high voltage source applies a voltage between the ring anode and the cathode. A current sensor senses a magnitude of any current flowing between the ring anode and the cathode via ionized gas molecules. A monitoring unit monitors the magnitude of the current sensed by the current sensor and activates an alarm when the magnitude of the current exceeds an acceptable magnitude.

Abstract: A system and a method detect contamination of a diaphragm in a capacitance diaphragm gauge wherein a contaminated diaphragm deflects less in the presence of pressure than an uncontaminated diaphragm. The system and method measure a base pressure. A DC voltage is applied between the diaphragm and a fixed electrode to cause the diaphragm to deflect to simulate an effective pressure. The system and method measure a combined pressure caused by the base pressure and the effective pressure. The system and method subtract the base pressure to determine the effective pressure caused by the static diaphragm deflection. If the measured effective pressure is less than an acceptable effective pressure, the system and method determine that the diaphragm is contaminated.

Abstract: In order to mitigate the negative effects of a change in atmospheric pressure, an improved capacitance diaphragm gauge (CDG) sensor incorporates an independent ambient atmospheric pressure sensor near the CDG sensor body. The ambient atmospheric sensor is located outside the CDG sensor body to sense the ambient atmospheric pressure surrounding the CDG sensor body. The ambient atmospheric sensor provides an output that represents the ambient atmospheric pressure. A sensor output processing circuit receives the output of the ambient atmospheric sensor as well as the output of the CDG sensor. The processing circuit utilizes the output from the ambient atmospheric pressure sensor to fine tune the CDG measurement of pressure by executing an in situ, real time, automatic calibration adjustment of the CDG.

Abstract: A system and method compensate for effects of gravity on the diaphragm of a capacitance diaphragm gauge (CDG). The CDG generates a measured absolute pressure value in response to an applied absolute pressure on an input of the CDG. The CDG is subjected to a variable orientation of the CDG with respect to the earth's surface that can cause inaccurate pressure measurements. A pressure measuring circuit generates a measured value of an applied absolute pressure provided to an input of the CDG. A tilt sensor generates at least one tilt sensor output value that is responsive to an orientation of the CDG with respect to the earth's surface. A processing system adjusts the measured absolute pressure value by a calibration factor to generate a calibrated absolute pressure value representing the applied absolute pressure, wherein the calibration factor is selected in response to the at least one tilt sensor output value.

Abstract: A system and method compensate for effects of gravity on the diaphragm of a capacitance diaphragm gauge (CDG). The CDG generates a measured absolute pressure value in response to an applied absolute pressure on an input of the CDG. The CDG is subjected to a variable orientation of the CDG with respect to the earth's surface that can cause inaccurate pressure measurements. A pressure measuring circuit generates a measured value of an applied absolute pressure provided to an input of the CDG. A tilt sensor generates at least one tilt sensor output value that is responsive to an orientation of the CDG with respect to the earth's surface. A processing system adjusts the measured absolute pressure value by a calibration factor to generate a calibrated absolute pressure value representing the applied absolute pressure, wherein the calibration factor is selected in response to the at least one tilt sensor output value.

Abstract: In order to mitigate the negative effects of a change in atmospheric pressure, an improved capacitance diaphragm gauge (CDG) sensor incorporates an independent ambient atmospheric pressure sensor near the CDG sensor body. The ambient atmospheric sensor is located outside the CDG sensor body to sense the ambient atmospheric pressure surrounding the CDG sensor body. The ambient atmospheric sensor provides an output that represents the ambient atmospheric pressure. A sensor output processing circuit receives the output of the ambient atmospheric sensor as well as the output of the CDG sensor. The processing circuit utilizes the output from the ambient atmospheric pressure sensor to fine tune the CDG measurement of pressure by executing an in situ, real time, automatic calibration adjustment of the CDG.

Abstract: A system and method compensate for effects of gravity on the diaphragm of a capacitance diaphragm gauge (CDG). The CDG generates a measured absolute pressure value in response to an applied absolute pressure on an input of the CDG. The CDG is subjected to a variable orientation of the CDG with respect to the earth's surface that can cause inaccurate pressure measurements. A pressure measuring circuit generates a measured value of an applied absolute pressure provided to an input of the CDG. A tilt sensor generates at least one tilt sensor output value that is responsive to an orientation of the CDG with respect to the earth's surface. A processing system adjusts the measured absolute pressure value by a calibration factor to generate a calibrated absolute pressure value representing the applied absolute pressure, wherein the calibration factor is selected in response to the at least one tilt sensor output value.

Abstract: A system and a method detect contamination of a diaphragm in a capacitance diaphragm gauge wherein a contaminated diaphragm deflects less in the presence of pressure than an uncontaminated diaphragm. The system and method measure a base pressure. A DC voltage is applied between the diaphragm and a fixed electrode to cause the diaphragm to deflect to simulate an effective pressure. The system and method measure a combined pressure caused by the base pressure and the effective pressure. The system and method subtract the base pressure to determine the effective pressure caused by the static diaphragm deflection. If the measured effective pressure is less than an acceptable effective pressure, the system and method determine that the diaphragm is contaminated.

Abstract: A system and method detect the presence of an unacceptable quantity of gas molecules in the reference vacuum cavity of a capacitance diaphragm gauge (CDG). An independent pressure transducer has an active portion exposed to the reference vacuum cavity. The transducer includes a ring anode, a cylindrical inner wall surface that forms at least one cathode, and a magnet positioned with respect to the ring anode such that the magnetic flux of the magnet is generally aligned with the central axis of the ring anode. A high voltage source applies a voltage between the ring anode and the cathode. A current sensor senses a magnitude of any current flowing between the ring anode and the cathode via ionized gas molecules. A monitoring unit monitors the magnitude of the current sensed by the current sensor and activates an alarm when the magnitude of the current exceeds an acceptable magnitude.