WO2003008915A1

WO2003008915A1 - Evaluation method for flowmeters

Info

Publication number: WO2003008915A1
Application number: PCT/CH2002/000373
Authority: WO
Inventors: Beat Kramer; Daniel Matter; Thomas Kleiner
Original assignee: Abb Research Ltd
Priority date: 2001-07-16
Filing date: 2002-07-09
Publication date: 2003-01-30
Also published as: DE10134455B4; DE10134455A1

Abstract

The invention relates to an evaluation method for flowmeters, which complicates the manipulation, by an unauthorised person, of the total amount used. According to the invention, instantaneous consumption values (Ci) are stored in a non-volatile memory, preferably an annular memory, and are periodically read out and analysed.

Description

DESCRIPTION

EVALUATION METHOD FOR FLOW MEASURING DEVICES

TECHNICAL AREA

The present invention relates to the field of flow meters such as gas meters or water meters. It relates to an evaluation method for determining total consumption according to the preamble of patent claim 1.

STATE OF THE ART

In the as yet unpublished European patent application No. 00810511.6, a gas energy measuring device based on an inexpensive CMOS flow sensor is shown, which determines natural gas consumption and, due to the measuring method used, enables calibration in standard volume or directly in gas energy. Calibration in standard volume is possible because the new gas meter determines the (pressure and temperature independent) mass flow and thus the conversion into a volume corresponding to the gas under standard conditions (e.g. 20 ° C, 1 bar) is easy to do. Since the measurement signal of this new gas meter is correctly weighted based on its sensitivity to the three main components (methane, ethane and propane) according to their specific calorific values, it is also possible to calibrate the device directly in energy.

In such an electronic gas meter, the physical parameters such as mass flow, volume flow or gas energy are measured periodically, for example every two seconds. These instantaneous values are then integrated in the gas meter itself and the integrated total consumption is periodically transmitted to a control center.

A great deal of effort is being made worldwide to manipulate measuring devices such as water meters, hot water meters, electrical energy meters or gas meters in such a way that they display a lower value than was actually obtained. A utility company or supplier suffers a significant financial loss as a result. PRESENTATION OF THE INVENTION

The object of the present invention is to increase the security against fraud in flowmeters and to discover attempts at manipulation. This object is achieved by an evaluation method for flowmeters with the features of claim 1.

According to the invention, integrated consumption intermediate values in a non-volatile, i.e. Memory insensitive to supply voltage failures, whereby not only the current, but also older instantaneous consumption values are saved. All these values are read out periodically and examined for manipulation indications.

A non-volatile ring memory is advantageously used and an associated time specification is also entered in the memory with the consumption values.

Advantageous embodiments emerge from the dependent claims.

BRIEF DESCRIPTION OF THE FIGURES

The invention is explained in more detail below on the basis of exemplary embodiments in conjunction with the drawings. Show it

Fig.l a sequence of daily consumption values of a consumer and Fig.2 the consumption in an integrated form as a result of instantaneous consumption values.

WAYS OF CARRYING OUT THE INVENTION

FIG. 1 shows a daily consumption of a certain quantity obtained from a consumer, such as gas, water, hot water, electricity, in arbitrary units over a period of 15 days. The daily consumption corresponds to a (mean) instantaneous value Fj of the flow of the quantity mentioned, ie a consumption per unit of time multiplied by the day length, or is itself a value obtained by integration over the day length. FIG. 2 shows the sequence of the instantaneous consumption values, which are obtained by integrating the instantaneous values Fj or adding the daily consumption values. According to the invention, these consumption Current values Cj or at least a part thereof are written in a non-volatile memory, for example an EEPROM or a flash memory, which is preferably part of the flow meter, and remain stored there. This not only protects the most up-to-date instantaneous consumption value against a sudden loss of power supply, but also instantaneous consumption values from the past.

These instantaneous consumption values Q are read out of the memory periodically, for example every two weeks, ie either transmitted to a central office or transferred to a mobile storage device. They are then analyzed as to whether, for example, there is a decrease from a value Cj to the next value ₊₁ . The latter indicates a manipulation attempt that would remain undetected if consumption was positive over the entire period. The data can also be evaluated to provide information about the customer's consumption profile.

The memory is preferably a ring memory or ring buffer, which can store just as many instantaneous consumption values Cj as there are between two readings. The most current value is written in the place of the oldest value. This automatically deletes the latter and memory management is reduced to a minimum.

In addition to the respective instantaneous consumption value Cj, a time specification Tj is also written in the memory, from which the time of the corresponding instantaneous value determination or its entry into the memory is evident. In this way, especially if the values are missing or suspicious, their timing can be determined again later. A user could also be tempted to illegally remove the flowmeter feed source to interrupt the determination of instantaneous flow values. In such a case, the residual energy currently present in a condenser of the flow meter, for example, can be used to write the current instantaneous consumption value into the memory. The occurrence of such a value, entered at a point in time outside the program, is again to be regarded as an indication of attempted manipulation.

In addition to the respective instantaneous consumption value Cj, a check sum can also be entered as an additional security element.

Claims

1. Evaluation method for flow measuring devices, a specific number of instantaneous flow values (Fj) being determined and integrated into instantaneous consumption values (Cj), which are stored in a non-volatile memory, and at the end of the Time period (T) a total consumption (C _to t) is read, characterized in that for analysis purposes together with the total consumption (C _to t) instantaneous consumption values (Cj) are read out from the non-volatile memory.

2. Evaluation method according to claim 1, characterized in that the non-volatile memory is a ring memory.

3. Evaluation method according to spoke 1, characterized in that the readout instantaneous consumption values (Cj) are examined for a temporal decrease.

4. Evaluation method according to claim 1, characterized in that an associated time (Tj) is additionally written in the memory for each instantaneous consumption value (Cj).

5. Evaluation method according to claim 4, characterized in that when a supply source of the flow measuring device is removed, the current most current consumption value is written into the memory out of the program.

6. Use of a readout method according to one of claims 1-5 in a flow meter, characterized in that the flow meter is a water meter, hot water meter, electrical energy meter or a gas meter.