METHOD FOR MONITORING A MEASURING DEVICE SYSTEM

Abstract

The method comprises producing a measurement signal (s1) having a signal parameter, followed with a temporal change (Δx1/Δt; Δx1′/Δt) of a primary measured variable (x1) and a temporal change (Δy1/Δt) of a disturbing variable (Δ1), and producing a measurement signal (s2) having a signal parameter, followed by a temporal change (Δx2/Δt; Δx2′/Δt) of a primary measured variable (x2). The method comprises ascertaining measured values (X.sub.I) of first type representing the primary measured variable (x1) or a secondary measured variable (f(x1) Δx1′) of measured values (X.sub.II) of second type representing the primary measured variable (x2) or a secondary measured variable (f(x2) Δx2′). The method comprises using measured values (X.sub.I) of first type and measured values (X.sub.II) of second type for ascertaining an error characterizing number (Err) representing a velocity error (ΔX.sub.I/ΔX.sub.II) caused by a change of the disturbing variable (y1).

Claims

1-20. (canceled)

21. A method for monitoring a measuring device system formed using a first measuring device (M1) and a second measuring device (M2), which method comprises steps as follows: producing a first measurement signal (s1) using the first measuring device (M1), such that the measurement signal (s1) has at least a first signal parameter, which follows with a temporal change including a temporal change (Δx1/Δt; Δx1′/Δt) of a first primary measured variable (x1) as well as also a temporal change (Δy1/Δt) of a disturbing variable (y1) independent of the first measured variable (x1); producing a second measurement signal (s2) using the second measuring device (M2), such that the measurement signal (s2) has at least a first signal parameter, which follows with a temporal change (Δx2/Δt; Δx2′/Δt) of a second primary measured variable (x2); ascertaining measured values (X.sub.I) of first type representing the first primary measured variable (x1) or a first secondary measured variable (f(x1).fwdarw.x1′) dependent thereon and based at least on the first signal parameter of the first measurement signal (s1); ascertaining measured values (X.sub.II) of second type representing the second primary measured variable (x2) or a second secondary measured variable (f(x2).fwdarw.x2′) dependent thereon and based at least on the first signal parameter of the second measurement signal (s2); using both measured values (X.sub.I) of first type as well as measured values (X.sub.II) of second type for ascertaining an error characterizing number (Err), wherein the error characterizing number (Err) represents a velocity error (ΔX.sub.I/ΔX.sub.II) of the measuring device system caused by a change of the disturbing variable (y1).

22. The method of claim 21, further comprising: producing a report, which indicates, as a function of the ascertained error characterizing number (Err), an extent of the disturbing variable (y1), and which is declared as an alarm.

23. The method of claim 21, further comprising: outputting measured values (X.sub.I) of first type and/or measured values (X.sub.II) of second type as qualified measured values of the measuring device system as a function of the ascertained error characterizing number (Err); and/or preventing an output at least of measured values (X.sub.I) of first type as qualified measured values of the measuring device system as a function of the ascertained error characterizing number (Err).

24. The method of claim 21, wherein ascertaining of the error characterizing number (Err) includes a calculating of at least one characterizing number value (X.sub.Err) quantifying the error characterizing number (Err) in such a manner that an increasing error characterizing number (Err) represents an increasing velocity error (ΔX.sub.I/□ΔX.sub.II).

25. The method of claim 21, further comprising: comparing the at least one characterizing number value of the error characterizing number (X.sub.Err) with a predetermined threshold value (TH.sub.Err), wherein the threshold value represents a maximum allowable velocity error of the measuring device system; as well as producing the report, when the characterizing number value (X.sub.Err) exceeds, or has exceeded, the threshold value (TH.sub.Err).

26. The method of claim 21, further comprising: outputting measured values (X.sub.I) of first type and/or measured values (X.sub.II) of second type as qualified measured values of the measuring device system, when the at least one characterizing number value has not exceeded the threshold value; and/or preventing output at least of measured values (X.sub.I) of first type as qualified measured values of the measuring device system, when the at least one characterizing number value has exceeded the threshold value.

27. The method of claim 21, wherein the ascertaining of the error characterizing number (X.sub.Err) includes ascertaining a measured value difference (ΔX.sub.I) of first type, namely a difference between two measured values (X.sub.I) of first type ascertained following one after another in time over a predetermined time interval (Δt), and ascertaining a measured value difference (ΔX.sub.II) of second type, namely a difference (ΔX.sub.II) between two measured values (X.sub.II) of second type ascertained following one after another in time over said time interval (Δt).

28. The method of claim 21, wherein the ascertaining of the error characterizing number (X.sub.Err) includes ascertaining a quotient of the measured value difference (ΔX.sub.I) of first type and the measured value difference (ΔX.sub.II) of second type.

29. The method of claim 21, wherein the ascertaining of the error characterizing number (Err) includes ascertaining both a rate of change (ΔX.sub.I/Δt) of the measured values (X.sub.I) of first type from the measured value difference (ΔX.sub.I) of first type and the predetermined time interval (Δt) as well as also a rate of change (ΔX.sub.II/Δt) of the measured values (X.sub.II) of second type from the measured value difference (ΔX.sub.I) of first type and the predetermined time interval (Δt).

30. The method of claim 21, wherein the ascertaining of the error characterizing number (X.sub.Err) includes ascertaining a quotient of the rate of change (ΔX.sub.I/Δt) of the measured values (X.sub.I) of first type and the rate of change (ΔX.sub.II/Δt) of the measured values (X.sub.II) of second type.

31. The method of claim 21, wherein the first measuring device is a Coriolis mass flow-measuring device.

32. The method of claim 21, wherein the first measuring device is adapted to measure mass flow and/or a volume flow of a fluid flowing through the measuring device.

33. The method of claim 21, wherein the second measuring device is a pressure difference-measuring device.

34. The method of claim 21, wherein the second measuring device is adapted to measure a pressure difference within a fluid flowing through the measuring device and/or volume flow of the fluid.

35. The method of claim 21, wherein the first primary measured variable (x1) is a mass flow (m;{dot over ( )}=dM/dt.fwdarw.x1) of a fluid flowing through the first measuring device; and/or wherein the first secondary measured variable (x1′) is a volume flow (v;{dot over ( )}=dV/dt.fwdarw.x1′) of a fluid flowing through the first measuring device; and/or wherein the second primary measured variable (x2) is a pressure difference (Δp.fwdarw.x2) within a fluid flowing through the second measuring device; and/or wherein the second secondary measured variable (x2′) is a volume flow (v;{dot over ( )}=dV/dt.fwdarw.x2′) of a fluid flowing through the second measuring device; and/or wherein the disturbing variable (y1) is a magnetic flux, or a magnetic flux density (B.fwdarw.y1), of a magnetic field within the first measuring device, or one caused by a magnet positioned outside of the first measuring device (M1).

36. The method of claim 21, wherein at least the first measurement signal (s1) has at least a second signal parameter, which follows with a temporal change a temporal change of a third primary measured variable (ρ.fwdarw.x3).

37. The method of claim 21, further comprising: applying the first measurement signal (s1) also for ascertaining measured values (X.sub.III) of third type representing the third primary measured variable (x3).

38. The method of claim 21, further comprising: using also measured values (X.sub.III) of third type for ascertaining the measured values (X.sub.I) of first type; and/or using also measured values (X.sub.III) of third type for ascertaining the measured values (X.sub.II) of second type.

39. The method of claim 36, wherein the third primary measured variable (x3) is a density (ρ.fwdarw.x3) of a fluid flowing through the first measuring device (M1).

40. The method of claim 21, further comprising: using the first measuring device (M1) for producing a third measurement signal (s3), which has at least one signal parameter, which follows with a temporal change both the temporal change (.fwdarw.x1/.fwdarw.t; Δx1′/Δt) of the first primary measured variable (x1) as well as also the temporal change (Δy1/Δt) of the disturbing variable (y1); as well as ascertaining measured values (X.sub.I) of first type based also on the at least one signal parameter of the third measurement signal (s3).

Description

[0033] FIGS. 1a, 1b, 1c, 1d different variants of a measuring device system suitable for the invention; and

[0034] FIG. 2 measurement data (measured values) experimentally ascertained with a measuring device system of one of the FIGS. 1a, 1b, 1c and 1d and at times influenced by a disturbance.

[0035] Shown schematically in FIGS. 1a, 1b, 1c and 1d are measuring device systems M1+M2 each formed by means of a first measuring device M1 and a second measuring device M2 for ascertaining measured values for two or more measured variables of a measured substance flowing in a process line, for example, a pipeline. In a measuring device system M1+M2, the first measuring device M1 is used for producing a, for example, electrical, first measurement signal s1, which, in turn, has at least one signal parameter, for example, an amplitude, a frequency or a phase angle, which follows with a temporal change a temporal change of a first primary measured variable x1, for example, a mass flow of the measured substance flowing in the measuring device system M1+M2. Moreover, the second measuring device is used, in order to produce a, for example, electrical, second measurement signal s2, which likewise has at least one signal parameter, which follows with a temporal change a temporal change of a second primary measured variable x2, in given cases, a second primary measured variable dependent on the first primary measured variable x1, for example, a second primary measured variable in the form of a pressure difference of the measured substance flowing in the measuring device system M1+M2, and in order to ascertain, based at least on the first signal parameter of the second measurement signal s2, measured values X.sub.II of second type, for example, digital measured values, representing the second primary measured variable x2 or a second secondary measured variable x2′ (f(x2).fwdarw.x2′) dependent thereon, for example, a volume flow of the measured substance flowing in the measuring device system M1+M2. Especially, the measuring device M1 can, furthermore, be adapted, or used, to measure as secondary measured variable x1′ the primary measured variable x2 measured by the measuring device M2, and/or the measuring device M2 can be adapted, or used, to measure as secondary measured variable x2′ the primary measured variable x1 measured by the measuring device M1; this, for example, also in such a manner that the measured values X.sub.I of first type represent the same measured variable as the measured values X.sub.II of second type. Alternatively or supplementally, the measuring device M2 can, coordinated with the measuring device M1, furthermore, be so selected that the primary measured variable x2 registered therewith depends on the primary measured variable x1. In an additional embodiment of the invention, the first measuring device M1 is, furthermore, adapted to measure as primary measured variable x1 mass flow m;{dot over ( )}1 (m;{dot over ( )}1=dM/dt.fwdarw.x1) and/or as a secondary measured variable x1′ a volume flow V;{dot over ( )}1 (V;{dot over ( )}1=dV/dt=m;{dot over ( )}/ρ.fwdarw.x1′) of the measured substance flowing through the measuring device M1, in given cases, also through the measuring device M2. Additionally, the measuring device M2 is adapted to measure as primary measured variable x2 a pressure p and/or a pressure difference Δp2 (Δp.fwdarw.x2) within the measured substance flowing through the measuring device M2, in given cases, also through the measuring device M1, and/or as secondary measured variable x2′ a volume flow v;{dot over ( )}2 (v;{dot over ( )}2=dV/dt=f(√Δp).fwdarw.x2′) of the measured substance. The measuring device M1 can, accordingly, be, for example, a Coriolis-flow-measuring device or, for example, also a magnetically inductive flow-measuring device and the measuring device M2 can be, for example, a pressure difference-flow-measuring device or a vortex-flow-measuring device.

[0036] For registering the primary measured variables and converting the measured variables into the measurement signals s1 (x1.fwdarw.s1), s2 (x2.fwdarw.s2) representing them, each of the measuring devices M1, M2 includes, integrated into the course of the process line, a measuring transducer, which—, as indicated in FIGS. 1a,1b,1c—is adapted to be flowed through by measured substance during operation of the measuring device system M1+M2. Furthermore, each of the measuring devices M1, M2 includes, electrically connected with its measuring transducer, a measuring device-electronics, which is, in turn, adapted to receive and correspondingly to evaluate the delivered measurement signals s1, s2, namely based thereon to ascertain the measured values X.sub.I of first type and measured values X.sub.II of second type, (s1.fwdarw.X.sub.I, s2.fwdarw.X.sub.II). In an additional embodiment of the invention, it is, furthermore, provided that at least the measurement signal s1 of the measuring device M1 has at least a second signal parameter (different from its first signal parameters), which follows with a temporal change a temporal change of a third primary measured variable x3, for example, a third primary measured variable independent of at least one of the primary measured variables x1, x2 and/or of the disturbing variable y1; this, especially, in such a manner that the measurement signal s1 can also be applied for ascertaining or calculating measured values X.sub.III of third type representing the third primary measured variable x3. Particularly for the above described case, in which the measuring device M1 is embodied as a Coriolis-mass flow-measuring device, the second signal parameter can be a frequency, for example, and the third primary measured variable x3 can be, for example, a density (ρ.fwdarw.x3) of the fluid flowing through the measuring device M1, in given cases, also the measuring device M2. Alternatively or supplementally, measured values X.sub.III of third type can, additionally, also be used for ascertaining measured values X.sub.I of first type and/or measured values X.sub.II of second type, for example, in order to convert a mass flow measured as a measured variable x1 into a volume flow (v;{dot over ( )}1=m;{dot over ( )}1/ρ.fwdarw.X.sub.I) or a volume flow measured as a measured variable x2 into a mass flow (m;{dot over ( )}2=V;{dot over ( )}2.Math.ρ.fwdarw.X.sub.II). Particularly for this case, the measuring device M1 can, furthermore, also be adapted, or used, to generate a, for example, likewise electrical and/or measurement signal s1 type-equal, third measurement signal s3, which has at least one signal parameter, for example, an amplitude, a frequency or a phase angle, which follows with a temporal change both the above referenced temporal change Δx1/Δt (Δx1′/Δt) of the primary measured variable x1 as well as also the above described temporal change Δy1/Δt of the disturbing variable y1. The signal parameter of the measurement signal s3 can in supplementation, of the signal parameter of the measurement signal s1, furthermore, be used to ascertain the measured values X.sub.I of first type.

[0037] As shown schematically in FIGS. 1a,1b,1c, the first and second measuring devices M1, M2, e.g. their measuring transducers, can be connected for series flow, for example, in such a manner that the same mass flow is present in both measuring devices M1, M2, e.g. both measuring transducers. The measuring transducers, or the measuring devices M1, M2 formed therewith, can, such as however, shown in FIG. 1d, also be connected for parallel flow, for example, in such a manner that the pressure drop in the measured substance flowing through the two measuring devices M1, M2, and the two measuring transducers is equal. Moreover, the measuring device system M1+M2 can also be formed in such a manner that type, construction and/or arrangement of the measuring devices M1, M2, and their measuring transducers, additionally, correspond, for example, also to measuring device systems known from US-A 2007/0084298, US-A 2011/0161018, US-A 2012/0042732, WO-A 2009/134268 or WO-A 2016/176224; this, for example, also in such a manner that, such as provided, among others, also in US-A 2007/0084298 or WO-A 2009/134268, at least one of the measuring devices M1, M2 generates its measurement signal s1,s2 by means of the two measuring transducers, or the measuring transducer of one of the two measuring devices M1 or M2, at least partially, also serves as a component of the measuring transducer of the other measuring device M1,M2, for example, the measured variable x2 measured by means of the measuring device M2 corresponds to a pressure drop across the measuring device M1, e.g. its measuring transducer (Δp.fwdarw.x2). Alternatively or supplementally, the measuring device system M1+M2 can, furthermore, be signal-coupled with a superordinated, measurement data registering and evaluating, computing unit C10, for example, a programmable logic controller (PLC), a flow computer or a work station (PC),—, for example, by means of data link and/or by means of radio connection—and the measuring device system can additionally, be adapted to send to the computer unit C10, at least at times, measured values of first and/or second type.

[0038] As already mentioned, in the case of a measuring device system M1+M2, one of the at least two measurement signals s1, s2 delivered from the measuring devices M1, M2, for example, the measurement signal s1 delivered by the measuring device M1, can have a high sensitivity, especially increased compared with the other of the measurement signals, for example, the measurement signal s2, to a disturbing variable y1 corresponding to an (external) disturbance () and independent of the primary measured variable; this, especially, in such a manner that its at least one (sensitive to the measured variable) signal parameter also follows with a corresponding temporal change a temporal change of the disturbing variable y1. As a result of such a disturbance () of one of the measuring devices, an accuracy of measurement of the measured values won based on the measurement signal can be corrupted and, associated therewith, an ability of the total measuring device system M1+M2 to function can be degraded in considerable measure; this, in given cases, also such that the measured values generated therewith, for example, such as shown by way of example in FIG. 2 based on experimentally ascertained measurement data, measured values X.sub.I of first type won from the measurement signal s1, have an unacceptably high measurement error. In the case of the measurement system of the invention M1+M2, especially the measurement signal s1 delivered by the measuring device M1 is sensitive both to the measured variable x1 as well as also the disturbing variable y1, in such a manner that its first signal parameter follows with a temporal change both the temporal change Δx1/Δt (Δx1′/Δt) of the primary measured variable x1 as well as also a temporal change Δy1/Δt of the disturbing variable y1, especially one independent of the first measured variable x1. Disturbing variable y1 can be, particularly for the above-described case, in which the measuring device M1 is a Coriolis-mass flow-measuring device measuring mass flow, for example, an accretion on an inner wall of one or more tubes of the measuring device or a magnetic flux, or a magnetic flux density (B.fwdarw.y1), of an external magnetic field, namely a magnetic field closing outside of the measuring device M1, or caused by a magnet positioned outside of the measuring device. In an additional embodiment of the invention, the measuring device M2 is so selected in coordination with the sensitivity of the measuring device M1, or of the measurement signal s1, to the disturbing variable y1 that the measurement signal s2 generated by means of the measuring device M2 has a lower sensitivity to the disturbing variable y1 than the measurement signal s1; this, for example, in such a manner that the measurement signal s2 has no or only a negligibly small sensitivity to the disturbing variable y1, or that its signal parameter is independent of the disturbing variable y1.

[0039] For monitoring measuring device system M1+M2, especially for checking the ability of the measuring device system M1+M2 to function and/or for determining a possibly arising disturbance () of the measuring device system M1+M2, according to the invention, firstly, an error characterizing number Err is ascertained, based both on measured values X.sub.I of first type as well as also based on measured values X.sub.II of second type, in such a manner that the error characterizing number Err represents a velocity error ΔX.sub.I/ΔX.sub.II of the measuring device system M1+M2 caused by a change (dy1/dt.fwdarw.Δy1/Δt) of the disturbing variable y1, namely a difference between a rate of change ΔX.sub.I/Δt of the measured values X.sub.I of first type and a simultaneous rate of change ΔX.sub.II/Δt of the measured values X.sub.II of second type or ascertained at the same time. The ascertaining of the error characterizing number Err can occur in the case of the measurement system M1+M2 of the invention, for example, in one of the measuring devices M1, M2, e.g. one of their measuring device-electronics, for example, as well as also schematically shown in FIGS. 1a and 1d, in the measuring device M1 or in the measuring device M2 (FIG. 1b). The error characterizing number Err can, however, for example, also, such as shown, among others, in FIG. 1c, be generated first in the above described superordinated computer unit C10 based on measured values of first and second type (X.sub.I, X.sub.II) transmitted from the measuring device system M1+M2 to the computer unit C10. As evident, for instance, from FIG. 2, based on the above described velocity error ΔX.sub.I/ΔX.sub.II, thus based already on its magnitude, or on the subsequently ascertained error characterizing number, a disturbance can be detected very quickly and very reliably, in that, directly, significant changes of the measurement signal s1, e.g. its signal parameter, effected by its arrival (or disappearance) are evaluated.

[0040] In an additional embodiment of the invention, it is, furthermore, provided as a function of the ascertained error characterizing number Err to produce a report, for example, issued as an alarm, at least qualitatively showing the presence of the disturbance, or an extent of the disturbing variable y1. The report can, for example, be output on one of the measuring devices M1, M2 or on each of the measuring devices M1, M2, for example, made visually perceivable by means of a corresponding signal light (LED) and/or a display unit of a measuring device. Alternatively or supplementally, the report can also be transmitted as a corresponding report to the above-mentioned computer unit C10. The error characterizing number Err can, for example, be ascertained in such a manner that it quantifies the disturbing variable y1, or its influence on the measurement signal s1, namely shown in the form of correspondingly calculated, numerical values; this, for example, in such a manner, that the characterizing number is ascertained in the form of a dimensionless, characterizing number (characteristic variable) and/or that an error characterizing number Err having a high numerical value represents a (relevant) disturbance effecting a high measurement error and an error characterizing number Err having a comparatively lower numerical value represents a disturbance effecting a comparatively lower, in given cases, even negligible, measurement error, and that an increasing error characterizing number Err represents an increasing velocity error ΔX.sub.I/ΔX.sub.II. The error characterizing number Err can, for example, however, also be so ascertained that it represents the presence of a disturbing variable y1 having a predetermined, for example, superelevated and/or critical level, or that it signals an associated influence on the measurement signal s1 only qualitatively, for example, the exceeding of a predetermined threshold value. Accordingly, according to an additional embodiment of the invention, it is provided to ascertain the error characterizing number Err in that (firstly) at least one, especially digital, characterizing number value X.sub.Err quantifying the error characterizing number Err, or the velocity error, is calculated; this, for example, also recurringly and/or in such a manner that a number of characterizing number values following one after another in time are calculated. The at least one characterizing number value X.sub.Err of the error characterizing number Err can then, for example, be compared with a predetermined threshold value TH.sub.Err, for example, a digital threshold value and/or one stored in the relevant measuring device-electronics, for example, a threshold value representing or quantifying a maximum allowable velocity error X.sub.Err,max of the measuring device system M1+M2 (X.sub.Err,max.fwdarw.TH.sub.Err). For the case, in which the characterizing number value X.sub.Err exceeds or has exceeded the threshold value TH.sub.Err, furthermore, the above-mentioned (error-) report can be correspondingly generated. In an additional embodiment of the invention, it is, furthermore, provided to output measured values X.sub.I of first type and/or measured values X.sub.II of second type as qualified measured values of the measuring device system as a function of the ascertained error characterizing number Err, for example, when the above-mentioned characterizing number value X.sub.Err has not exceeded the set threshold value TH.sub.Err, or to prevent at least one output of measured values X.sub.I of first type as qualified measured values of the measuring device system as a function of the ascertained error characterizing number Err, in case namely the error characterizing number Err signals a too high measurement error for measured values X.sub.I of first type, or when the above-mentioned characterizing number value X.sub.Err has exceeded the set threshold value TH.sub.Err. The characterizing number value X.sub.Err can, for example, be ascertained with the same updating rate as the measured values of first and second type.

[0041] In an additional embodiment of the invention, it is, furthermore, provided for the ascertaining of the error characterizing number X.sub.Err and for calculating one or more characterizing number values X.sub.Err, firstly, to ascertain a measured value difference ΔX.sub.I of first type, namely a difference between two measured values X.sub.I of first type ascertained over a predetermined time interval Δt and one after another in time, and a measured value difference ΔX.sub.II of second type, namely a difference ΔX.sub.II of two measured values X.sub.II of second type ascertained over the time interval Δt and one after another in time. Based on the measured value differences of first type and of second type, the error characterizing number X.sub.Err and the characterizing number values X.sub.Err can, for example, be calculated in that, firstly, there are ascertained both a rate of change ΔX.sub.I/Δt of the measured values X.sub.I of first type from the measured value difference ΔX.sub.I of first type and the predetermined time interval Δt, as well as also a rate of change ΔX.sub.II/Δt of the measured values X.sub.II of second type from the measured value difference ΔX.sub.I of first type and the predetermined time interval Δt, for example, in each case, as an instantaneous or an average rate of change, and thereafter a quotient is calculated from the rate of change ΔX.sub.I/Δt of the measured values X.sub.I of first type and the rate of change ΔX.sub.II/Δt of the measured values X.sub.II of second type. Alternatively or supplementally, the error characterizing number X.sub.Err and the characterizing number values X.sub.Err can be ascertained based on of the above described measured value differences ΔX.sub.II, ΔX.sub.I of first and of second type very easily also by ascertaining, especially calculating, a corresponding quotient ΔX.sub.I/ΔX.sub.II (difference quotient) from the measured value difference ΔX.sub.I of first type and the measured value difference ΔX.sub.II of second type.