Method for detecting and/or monitoring a physical or chemical process variable

• US 20060015292A1
• Filed: 12/18/2002
• Published: 01/19/2006
• Est. Priority Date: 12/21/2001
• Status: Abandoned Application

• Current Assignee: Endress + Hauser GmbH + Company KG (Endress+Hauser AG)
• Original Assignee: Endress + Hauser GmbH + Company KG (Endress+Hauser AG)
• Inventors: Lubcke, Wolfgang
• Application Number:
  US10/498,510
• Publication Number:
  US 20060015292A1
• Time in Patent Office: Days
• US Class Current: 702/183
• CPC Class Codes: G01D 3/08 with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown
• CPC Class Codes: G01F 23/284 Electromagnetic waves
• CPC Class Codes: G01F 25/20 of apparatus for measuring liquid level

Abstract

The method of the invention determines and/or monitors a physical or chemical process parameter of a liquid or solid medium. The invention provides measurements which represent a physical or chemical parameter, are taken. A measurement approximately constant over a predetermined time interval is used for recognizing a malfunction of a measuring device, especially for recognizing accretions on the sensor side thereof or cumulatively, a measurement approximately constant over a predetermined time interval is used for recognizing a malfunction of the electronics of the measuring device. Also alternatively or cumulatively, a measurement approximately constant over a predetermined time interval is used for recognizing a process-side change and/or a malfunction caused by the process.

Claims

1-12. -12. (canceled)

13. A method for determining and/or monitoring a physical or chemical process parameter of a liquid or solid medium, wherein measurements are taken representing the physical or chemical process parameter, the method comprises the steps of:

using a measurement which is approximately constant over a predetermined time interval for recognizing a malfunction of a measuring device, especially for recognizing an accretion on the sensor-side of the measuring device; and

/or

using a measurement which is approximately constant over a predetermined time interval for recognizing a malfunction of the electronics of the measuring device; and

/or

using a measurement which is approximately constant over a predetermined time interval to recognize a change on the process-side and/or a malfunction caused by the physical or chemical process.

18. The method as claimed in claim 13, wherein:

the measurements are stored over a predetermined time period as historical data; and

a malfunction, which establishes itself unobtrusively, is recognized based on the historical data.

20. The method as claimed in claim 13, wherein:

the fill level of the medium in a container, the mass, the temperature, the pressure, the density, the viscosity, the flow rate, the turbidity, the conductivity, the pH-value and/or the chemical composition of the medium is determined.

21. The method as claimed in claim 20, wherein:

the fill level of a fill substance in a container is determined via the travel time of freely radiated or guided measuring signals.

22. The method as claimed in claim 21, wherein:

a measurement representing the fill level is determined via the echo curve, which represents the amplitudes of the measuring signals as a function of travel time or travel distance.

24. The method as claimed in claim 20, wherein:

the fill level of the medium in a container, the mass, the temperature, the pressure, the density, the viscosity, the flow rate, the turbidity, the conductivity, the pH-value and/or the chemical composition of the medium is determined.

25. The method as claimed in claim 21, wherein:

a measurement representing the fill level is determined via the echo curve, which represents the amplitudes of the measuring signals as a function of travel time or travel distance.

14. A method for determining and/or monitoring a physical or chemical process parameter of a liquid or solid medium in a container, comprising the steps of:

taking measurements representing the physical or chemical process parameter over a plurality of measurement cycles; and

making a determination based on the measurements, of the average rate of change of the measurements and/or the average length of a time interval in which the measurements are constant, wherein;

a malfunction is indicated, when the average rate of change of the measurements is subceeded and/or when the average length of the time interval, in which a measurement remains constant, is exceeded.

15. The method as claimed in claim 14, wherein:

a malfunction is indicated, when the rate of change of the measurements is smaller than the minimum determined rate of change and/or when the time interval, in which the measurements are approximately constant, is greater than the maximum determined time interval.

16. The method as claimed in claim 14, wherein:

a malfunction is first indicated, when a predetermined tolerance range of;

the rate of change of the measurements, or, respectively, the time interval, in which a measurement is approximately constant, is subceeded, or, respectively, exceeded.

17. A method for determining and/or monitoring a physical or chemical process parameter of a liquid or solid medium in a container, comprising the steps of:

taking measurements respecting the physical or chemical process parameter over a predetermined time interval, wherein, for the case that the measurement remains approximately constant during the time interval, at least one additional process and/or system parameter is determined;

using said additional process and/or system parameter to perform a plausibility check, wherein the plausibility check is used to determine whether the constant measurement is to be interpreted as a malfunction; and

reporting an error in the case of the occurrence of a recognized malfunction.

19. The method as claimed in claim 17, wherein:

the measurements are stored over a predetermined time period as historical data; and

a malfunction, which establishes itself unobtrusively, is recognized based on the historical data.

23. The method as claimed in claim 17, wherein:

the fill level of the medium in a container, the mass, the temperature, the pressure, the density, the viscosity, the flow rate, the turbidity, the conductivity, the pH-value and/or the chemical composition of the medium is determined.

26. A method for monitoring the malfunction of a field device for determining and/or monitoring the fill level of a medium in a container, wherein the field device has an electronics section, a coupling section and an antenna, the method comprising the steps of:

emitting high-frequency measuring signals in the direction of the fill substance and reflected at the surface of the fill substance;

determining an echo curve, which shows the amplitudes of the measuring signals as a function of the travel time or travel distance of the measuring signals; and

using at least one echo signal, which occurs before the actual useful echo signal representing the fill level of the medium in the container, for recognizing a malfunction in the electronics section or the coupling section.

27. The method as claimed in claim 26, further comprising the steps of:

comparing the current echo curve with a stored echo curve; and

recognizing and interpreting a malfunction and the kind of malfunction based on a variance between the current echo curve and the stored echo curve.

28. Method as claimed in claim 26, wherein:

historical data is used for recognizing a malfunction of the fill level measuring device.

29. Method as claimed in claim 27, wherein:

historical data is used for recognizing a malfunction of the fill level measuring device.