Abstract: An apparatus for holding a sensor for sensing the contents of a vessel is provided. The apparatus has an extended position where the sensor is exposed to the contents and a retracted position for cleaning the sensor. The apparatus includes a process connection configured to connect the apparatus to the wall of the vessel. The process connection defines an aperture including a first rim, a second rim angularly displaced from the first rim, and a sidewall extending between the first rim and the second rim. The sidewall is angularly displaced from the first rim by no less than 135 degrees.

Abstract: A method and apparatus for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining a reference signal along a probe in the vessel, establishing a first fiducial reference point, a reference end of probe location, a measuring length and a maximum probe length. The method also includes the steps of periodically detecting a TDR signal along the probe, establishing a second fiducial reference point, a detected end of probe location, an end of probe peak to peak amplitude, and attempting to determine a process variable reflection on the TDR signal. The method indicates a broken cable condition, a loss of high frequency connection, a low amplitude reflection condition, an empty vessel condition.

Abstract: An apparatus for holding a sensor for sensing the contents of a vessel is provided. The apparatus has an extended position where the sensor is exposed to the contents and a retracted position for cleaning the sensor. The apparatus includes a process connection configured to connect the apparatus to the wall of the vessel. The process connection defines an aperture including a first rim, a second rim angularly displaced from the first rim, and a sidewall extending between the first rim and the second rim. The sidewall is angularly displaced from the first rim by no less than 135 degrees.

Abstract: A method and apparatus for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining an initial reference signal along a probe, storing the initial reference signal as an active reference signal, periodically detecting a TDR signal along the probe in the vessel, and computing the output result using the TDR signal and the active reference signal. The method also includes the steps of determining an appropriate time for updating the active reference signal, automatically computing an updated reference signal at the appropriate time, and overwriting the active reference signal with the updated reference signal for use in subsequent computations of the output result.

Abstract: A sensor apparatus is provided for transmitting electrical pulses from a signal line into and out of a vessel to measure a process variable. The sensor apparatus has a mounting section, at least one dielectric insert, a conductive transitioning pin, a metallic insert, a probe element, and an electrical connector to the signal line. The mounting section is configured to be coupled to the vessel and includes a central aperture with a first tapered surface. The dielectric insert has a second and third tapered surface. The second tapered surface is configured to engage the first tapered surface of the mounting section to prevent movement of the dielectric insert in a direction away from the mounting section.

Abstract: A sensor apparatus for transmitting electrical pulses from a signal line into and out of a vessel to measure a process variable. The sensor apparatus includes a mounting section configured to be coupled to the vessel, a conductive probe element, a dielectric insert located within the mounting section, a conductive pin coupled to the top end of the probe element, and an electrical connector coupled to the conductive pin. The conductive probe element has a predetermined diameter and is formed to include a section having a reduced diameter adjacent a top end of the probe element and a tapered section providing transition from the probe element to the reduced diameter section. The dielectric insert includes an inwardly tapered section to prevent movement of the probe element in a direction toward the mounting section and an outwardly tapered section.

Abstract: A method for processing a time domain reflectometry (TDR) signal having a plurality of reflection pulses to generate a valid output result corresponding to a process variable for a material in a vessel. The method includes the steps of determining a background signal for a probe and detecting a sample TDR signal for the probe in the vessel. At least one transition point is established on the sample TDR signal and the background signal. A portion of the sample TDR signal on one side of the at least one transition point is combined with a portion of the background signal on the other side of the at least one transition point to establish an initial boundary signal, and the initial boundary signal is stored. The method also includes the steps of detecting the TDR signal and calculating the output result using the initial boundary signal.

Abstract: An apparatus and method for processing a time domain reflectometry (TDR) signal to generate an output result corresponding to a valid process variable. The method includes the steps of processing the TDR signal using at least two different techniques for detecting a valid reflection pulse generated by the process variable to calculate an independent result using each of the at least two techniques, and applying a weighted factor to the independent results from each of the at least two different techniques to provide weighted output results. The method also includes the steps of comparing the weighted output results, and selecting the valid output result from the weighted output results based on the comparing step. In the illustrated method, the comparing step includes the step of summing the weighted factors for each independent result.

Abstract: A sensor apparatus is provided for transmitting electrical pulses from a signal line into and out of a vessel to measure a process variable. The sensor apparatus has a mounting section, at least one dielectric insert, a conductive transitioning pin, a metallic insert, a probe element, and an electrical connector to the signal line. The mounting section is configured to be coupled to the vessel and includes a central aperture with a first tapered surface. The dielectric insert has a second and third tapered surface. The second tapered surface is configured to engage the first tapered surface of the mounting section to prevent movement of the dielectric insert in a direction away from the mounting section. The conductive transitioning pin has a fourth tapered surface configured to engage the third tapered surface of the dielectric insert.

Abstract: A sensor apparatus is provided for transmitting electrical pulses from a signal line into a vessel to measure a process parameter. The sensor apparatus includes a lower flange configured to be coupled to the vessel. The lower flange is formed to include a central aperture defined by a radially outwardly tapered surface located adjacent a top surface of the lower flange. The apparatus also includes a conductive probe element including a head having first and second radially outwardly tapered surfaces and an elongated conductive portion extending away from the head. The first tapered surface of the head is configured to engage the tapered surface of the lower flange to prevent movement of the probe element in a direction toward the lower flange. The apparatus further includes an upper flange configured to be coupled to the lower flange to secure the probe element to the lower flange.