Measuring method for a measured variable dependent on auxiliary measured variables

Patent metadata

Field	Value
Publication number	US-9689708-B2
Application number	US-201113812160-A
Country	US
Kind code	B2
Filing date	Jun 20, 2011
Priority date	Jul 28, 2010
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A method for determining a value of a measured variable, which is a function of a first auxiliary measured variable and at least a second auxiliary measured variable, comprising: registering and providing a sequence of measured values of the first auxiliary measured variable over at least a first time range; providing a value of the second auxiliary measured variable, wherein the point in time of registering the provided value lies in the first time range; selecting a value of the first auxiliary measured variable from the sequence of measured values of the first auxiliary measured variable as a function of information concerning point in time of registering the provided value of the second auxiliary measured variable; and ascertaining a value of the measured variable as a function of the selected value of the first auxiliary measured variable and the value of the second auxiliary measured variable.

First claim

The invention claimed is:

1. A method for determining a value of a measured variable, which is a function of a first auxiliary measured variable and at least a second auxiliary measured variable, comprising the steps of:
registering and providing a sequence of measured values of the first auxiliary measured variable over at least a first time range;
providing a value of the second auxiliary measured variable, wherein the point in time of registering the provided value lies in the first time range;
selecting a value of the first auxiliary measured variable from the sequence of measured values of the first auxiliary measured variable as a function of information concerning point in time of registering the provided value of the second auxiliary measured variable; and
ascertaining a value of the measured variable as a function of the selected value of the first auxiliary measured variable and the value of the second auxiliary measured variable;
wherein repetition frequency of the registering of the sequence of values of the first auxiliary measured variable is a function of a clock signal of the first measuring device;
the clocking frequency of the first measuring device is variable in a range of variation of no more than 10%; and
by variation of the clocking frequency the repetition frequency for registering the values of the first auxiliary measured variable is varied, in order to minimize a deviation between the point in time of the registering of the value of the first auxiliary measured variable to be selected in each case and the point in time of registering the provided value of the second auxiliary measured variable.

2. The method as claimed in claim 1 , wherein:
providing of the value of the second auxiliary measured variable occurs upon a demand that the value be provided.

3. The method as claimed in claim 2 , wherein:
the registering of the value of the second auxiliary measured variable to be provided occurs upon the demand that the value be provided.

4. The method as claimed in claim 2 , wherein:
a sequence of values of the second auxiliary measured variable is registered; and
upon demand that a value of the second auxiliary measured variable be provided, the most up-to-date, available registered value of the sequence is provided.

5. The method as claimed in claim 1 , wherein:
the value of the second auxiliary measured variable is provided together with information concerning point in time of registering the provided value of the second auxiliary measured variable.

6. The method as claimed in claim 5 , wherein:
there is transmitted, together with the value of the second auxiliary measured variable, the value of a delay time, which has passed between registering of the value of the second auxiliary measured variable and the providing of the value of the second auxiliary measured variable.

7. The method as claimed in claim 1 , wherein:
based on point in time of receipt of a data frame, with which the value of the second auxiliary measured variable is provided, and based on a delay time between registering of the value of the second auxiliary measured variable and the providing of the data frame, the point in time of the registering of the value of the second auxiliary measured variable is ascertained.

8. The method as claimed in claim 5 , wherein:
there is provided with the value of the second auxiliary measured variable a time signal, which expresses the point in time of the registering according to a system time of a measuring device, which registers and provides the value of the second auxiliary measured variable.

9. Method as claimed in claim 8 , wherein:
the system time of the second measuring device is synchronized with the system time of a first measuring device, which registers the sequence of values of the first auxiliary measured variable.

10. The method as claimed in claim 9 , wherein:
the synchronizing occurs by having the first measuring device request the system time of the second measuring device, which then transmits its system time to the first measuring device, and the first measuring device compares the system time of the second measuring device with its own system time and transmits a correction value for the system time of the second device to the second device, wherein the second measuring device corrects its system time using the transmitted correction value.

11. The method as claimed in claim 1 , wherein:
the provided values of the sequence of values of the first auxiliary measured variable are stored in a ring buffer.

12. The method as claimed in claim 1 , wherein:
the values of the first auxiliary measured variable are registered by a first measuring device;
the values of the second auxiliary measured variable are registered by a second measuring device;
the first and the second field devices are connected with one another via a digital data communication means, and wherein the first measuring device is operated as master; and
the second measuring device is operated as slave.

13. The method as claimed in claim 12 , wherein:
the first measuring device and the second measuring device communicate with one another via a HART protocol.

14. The method as claimed in claim 13 , wherein:
the second measuring device provides the value of the second auxiliary measured variable in a HART multidrop frame.

15. The method as claimed in claim 1 , wherein:
the measured variable is furthermore a function of at least a third auxiliary measured variable, wherein a sequence of values of the third auxiliary measured variable is provided and a value of the third auxiliary measured variable enters into the ascertaining of a value of the measured variable.

16. The method as claimed in claim 15 , wherein:
the sequence of values of the third auxiliary measured variable is provided with information concerning respective points in time of the registering of the values.

17. The method as claimed in claim 1 , wherein:
the clocking frequency of the first measuring device is variable in a range of variation of no more than 5%.

Assignees

• Girardey Romuald
• Dieterle Roland
• Schlachter Marc
• Endress Hauser Gmbh Co Kg

Inventors

• Girardey Romuald
• Dieterle Roland
• Schlachter Marc

Classifications

• G01L15/00

  Devices or apparatus for measuring two or more fluid pressure values simultaneously · CPC title

• G06F15/00

  Digital computers in general (details G06F1/00 – G06F13/00); Data processing equipment in general · CPC title

• G04F13/00

  Apparatus for measuring unknown time intervals by means not provided for in groups G04F5/00 - G04F10/00 · CPC title

• G01D1/14 Primary

  giving a distribution function of a value, i.e. number of times the value comes within specified ranges of amplitude · CPC title

• G01F1/34 Primary

  by measuring pressure or differential pressure · CPC title