Probe mapping diagnostic methods
First Claim
1. 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, said method comprising the steps of:
- determining a reference signal along a probe in said vessel;
establishing a reference end of probe location using said reference signal;
periodically detecting a TDR signal along said probe;
determining a detected end of probe location on said TDR signal;
attempting to detect a process variable reflection on said TDR signal;
determining a system status based upon said reference end of probe location, said detected end of probe location and said process variable reflection; and
computing said output result when said system status is functional.
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Accused Products
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. Distances and locations on the reference signal are computed in relation to the first fiducial reference point, and distances and locations on the TDR signal are computed in relation to the second fiducial reference point.
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Citations
16 Claims
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1. 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, said method comprising the steps of:
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determining a reference signal along a probe in said vessel;
establishing a reference end of probe location using said reference signal;
periodically detecting a TDR signal along said probe;
determining a detected end of probe location on said TDR signal;
attempting to detect a process variable reflection on said TDR signal;
determining a system status based upon said reference end of probe location, said detected end of probe location and said process variable reflection; and
computing said output result when said system status is functional. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An 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, said apparatus comprising:
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means for determining a reference signal along a probe in said vessel;
means for establishing a reference end of probe location using said reference signal;
means for periodically detecting a TDR signal along said probe;
means for determining a detected end of probe location on said TDR signal;
means for attempting to detect a process variable reflection on said TDR signal;
means for determining a system status based upon said reference end of probe location, said detected end of probe location and said process variable reflection; and
means for computing said output result when said system status is functional. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification