CN110044431B - Transmitter and flowmeter - Google Patents
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- CN110044431B CN110044431B CN201810040074.6A CN201810040074A CN110044431B CN 110044431 B CN110044431 B CN 110044431B CN 201810040074 A CN201810040074 A CN 201810040074A CN 110044431 B CN110044431 B CN 110044431B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/78—Direct mass flowmeters
- G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
- G01F1/84—Coriolis or gyroscopic mass flowmeters
Abstract
The present disclosure relates to a transmitter for a coriolis flow meter and a coriolis flow meter. According to one embodiment of the present disclosure, a transmitter for a coriolis flowmeter includes: switch element, first passageway, second passageway and signal processor. The signal processor is configured to receive a first channel output signal and a second channel output signal and determine a time delay difference between a first time delay of the first channel output signal and a second time delay of the second channel output signal; wherein the electrical connection state of the switch unit includes a first electrical connection state and a second electrical connection state. The technical scheme of the disclosure can improve the confidence of flow measurement.
Description
Technical Field
The present disclosure relates generally to flow meters, and more particularly, to transmitters for coriolis flow meters and coriolis flow meters.
Background
Coriolis flowmeters are a common type of flow measurement device. As disclosed in chinese patent publication No. CN1087422C, coriolis flowmeter can determine the flow rate by determining the time delay.
Disclosure of Invention
A brief summary of the disclosure is provided below in order to provide a basic understanding of some aspects of the disclosure. It should be understood that this summary is not an exhaustive overview of the disclosure. The following summary is not intended to identify key or critical elements of the disclosure, nor is it intended to be limiting as to the scope of the disclosure. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.
In view of improving the confidence of the flow measurement of the coriolis flowmeter, the following is conceived.
According to an aspect of the present disclosure, there is provided a transmitter for a coriolis flowmeter, comprising: a first channel having a first operational amplifier and configured to output a first channel output signal; a second channel having a second operational amplifier and configured to output a second channel output signal; a signal processor configured to receive the first channel output signal and the second channel output signal and to determine a time delay difference between the first channel output signal and the second channel output signal; and a switching unit comprising at least one switching pair and configured to switch an input signal pair of at least one of the first channel and the second channel between two input signal pairs by switching the switching unit between a first electrical connection state and a second electrical connection state, such that the signal processor is able to determine a current channel time delay difference and a current flow rate of the transmitter; wherein the signal processor is further configured to output a switch control signal to control an electrical connection state of the switching unit; the signal sources of the two input signal pairs are different from each other; the first channel is configured to receive a first differential signal pair output from the right pickoff during vibration of a measurement tube of a coriolis flow meter driven by a driver of the coriolis flow meter with a drive signal; and the second channel is configured to receive a second differential signal pair output from the left sensor during vibration of the measurement tube of the coriolis flow meter driven by the driver of the coriolis flow meter with the drive signal.
According to an aspect of the present disclosure, there is provided a coriolis flow meter including: the transmitter; a measurement tube; a driver mounted on the measurement pipe and configured to drive the measurement pipe to vibrate with a drive signal; a left sensor mounted on the measurement tube and configured to output a first differential signal pair; and a right sensor mounted on the measurement pipe and configured to output a second differential signal pair.
The technical scheme of the disclosure can improve the flow measurement confidence of the Coriolis flowmeter.
Drawings
The disclosure may be better understood by reference to the following description taken in conjunction with the accompanying drawings. It should be understood that the drawings are not necessarily drawn to scale. In the drawings:
fig. 1 is a schematic diagram showing a structure of a coriolis flow meter according to a comparative example;
fig. 2a is a schematic diagram showing a circuit configuration of a coriolis flow meter according to a comparative example;
fig. 2b shows a block diagram of a circuit configuration of a coriolis flow meter according to a comparative example;
fig. 3 is a schematic diagram of a structure of a coriolis flow meter according to an embodiment of the present disclosure;
FIG. 4a is a schematic diagram showing the circuit configuration of the Coriolis flow meter in FIG. 3;
FIG. 4b shows a block diagram of the circuit configuration of the Coriolis flow meter in FIG. 4 a;
fig. 5a is a schematic diagram of a circuit configuration of a coriolis flow meter according to an embodiment of the present disclosure;
FIG. 5b shows a block diagram of the circuit configuration of the Coriolis flowmeter of FIG. 5 a;
fig. 6a is a schematic diagram of a circuit configuration of a coriolis flow meter according to another embodiment of the present disclosure;
FIG. 6b shows a block diagram of the circuit configuration of the Coriolis flowmeter of FIG. 6 a;
fig. 7a is a schematic diagram of a circuit configuration of a coriolis flow meter according to yet another embodiment of the present disclosure;
FIG. 7b shows a block diagram of the circuit configuration of the Coriolis flowmeter of FIG. 7 a;
fig. 8 is a schematic diagram illustrating a non-periodic switching control signal according to an embodiment of the present disclosure;
FIG. 9 is a schematic diagram illustrating a periodic switch control signal according to one embodiment of the present disclosure; and
fig. 10 is a graph showing the change in the reference time delay difference at different temperatures.
Detailed Description
Exemplary embodiments of the present disclosure will be described hereinafter with reference to the accompanying drawings. In the interest of clarity and conciseness, not all features of an actual implementation are described in the specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions may be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another.
Here, it is also to be noted that, in order to avoid obscuring the present disclosure by unnecessary details, only the device structure closely related to the scheme according to the present disclosure is shown in the drawings, and other details not so much related to the present disclosure are omitted.
In order to facilitate understanding of the technical solution of the present disclosure, the coriolis flowmeter in the comparative example will be described below.
Fig. 1 is a schematic diagram showing the structure of a coriolis flow meter 10' according to a comparative example. Fig. 2a is a schematic diagram showing a circuit configuration of a coriolis flow meter 10' according to a comparative example. Fig. 2b shows a block diagram of the circuit configuration of a coriolis flow meter according to a comparative example. Coriolis flowmeter 10' includes: line interface, measurement tube 103, driver D, coriolis sensor, and transmitter 105'. The pipeline interfaces include a first pipeline interface 101a and a second pipeline interface 101 b. The first line interface 101a is used for connection with a first interface (not shown) of a line containing a fluid F flowing at a current flow rate R. The second line interface 101b is for connection with a second interface (not shown) of a line. The coriolis sensor includes a right sensor Sa and a left sensor Sb. As shown in fig. 1, the measurement pipe 103 is configured with a pair of pipes arranged in parallel, i.e., a first measurement pipe 103a and a second measurement pipe 103 b. The pipe is for example a U-shaped pipe. The right sensor Sa and the left sensor Sb may comprise a coil and a magnet, wherein when the coil moves relative to the magnet, a signal associated with the movement will be induced in the coil. The right sensor Sa and the left sensor Sb are mounted on the measurement pipe 103. Specifically, for example, the left sensor Sb is mounted on the measurement pipe on the inlet side, and the right sensor Sa is mounted on the measurement pipe on the outlet side. The fluid F flowing out of the line flows back to the line via the second line connection 101b, the inlet-side measuring tube, the outlet-side measuring tube and the first line connection 101 a. As shown in fig. 1, a driver D is also mounted on the measurement pipe 103. The driver D can drive the measuring tube 103 into vibration with a drive signal S0. The right sensor Sa senses vibrations of the measurement pipe on the outlet side and gives a first differential signal pair Pa related to the vibrations, wherein the first differential signal pair Pa is composed of signals Sa1 and Sa 2. The first differential signal pair Pa is output via a right sensor output terminal pair Ps1, wherein the right sensor output terminal pair Ps1 is composed of output terminals S11 and S12. The left sensor Sb senses the vibrations of the measuring tube on the inlet side and gives a second differential signal pair Pb which is dependent on the vibrations, wherein the second differential signal pair Pb consists of the signals Sb1 and Sb 2. The second differential signal pair Pb is output via the left sensor output terminal pair Ps2, wherein the left sensor output terminal pair Ps2 is composed of output terminals S21 and S22. The vibrations of the measuring tube 103 are related to the drive signal S0, the measuring tube, the flow and the direction of flow of the fluid in the measuring tube. According to the coriolis theory, the measurement lines on the inlet side and the measurement lines on the outlet side vibrate differently for the current flow rate R, so that the first differential signal pair Pa differs from the second differential signal pair Pb. When coriolis flowmeter 10 'is used to measure the current flow rate R, transmitter 105' is electrically connected to left sensor Sb, right sensor Sa, and driver D.
As shown in fig. 2a and 2b, the transmitter 105 'includes a signal processor SP'. The signal processor SP' is capable of outputting a driver control signal Sc that controls the driver D. The first differential signal pair Pa is input to the signal processor SP 'via a first channel Cha'. The second differential signal pair Pb is input to the signal processor SP 'via a second path Chb'. As shown in fig. 2a and 2b, the first channel Cha' has a first channel input pair Pc1 receiving the first differential signal pair Pa, wherein the first channel input pair Pc1 has channel input terminals C11 and C12; the second channel Chb' has a second channel input pair Pc2 that receives the second differential signal pair Pb, wherein the second channel input pair Pc2 has channel input terminals C21 and C22. Note that, when the coriolis flow meter 10' is operating, the right sensor output terminal pair Ps1 is electrically connected to the first channel input terminal pair Pc1 (i.e., S11 is electrically connected to C11, and S12 is electrically connected to C12) to receive the first differential signal pair Pa; the left sensor output terminal pair Ps2 is electrically connected to the second channel input terminal pair Pc2 (i.e., S21 is electrically connected to C21, and S22 is electrically connected to C22) to receive the second differential signal pair Pb. As can be seen, the input signal pair of the first channel Cha' comes from the signal source right sensor Sa; the input signal to the second channel Chb' is from the signal source right sensor Sb. The first channel Cha 'outputs a first channel output signal Scha, and the second channel Chb' outputs a second channel output signal Schb. The first channel Cha' has leads, an operational amplifier OA1, resistors R1, R2, R3, and a capacitor C1. The second channel Chb' has leads, an operational amplifier OA2, resistors R5, R6, R7, and a capacitor C2. The signal processor SP' receives the first channel output signal Scha and the second channel output signal Schb. The signal processor SP' is able to determine the first channel output signal Scha relative to the driveA first time delay difference Δ t between a first time delay Ta of the signal S0 and a second time delay Tb of the second channel output signal Schb relative to the drive signal S0, wherein the first time delay Ta is equal in value to a phase difference between the first channel output signal Scha and the drive signal S0
The corresponding time (i.e.,
ω is the angular frequency of the drive signal S0), the second time delay Tb is equal in value to the phase difference between the second channel output signal Schb and the drive signal S0
The corresponding time (i.e.,
). In accordance with the principles of coriolis flow meters, the signal processor SP 'calculates the flow rate R' as the current flow rate, typically by equation 1.
R'＝FCF*(Δt-ΔT0) (1)
Where FCF is a flow calibration factor, the first time delay difference Δ T is Ta-Tb, and Δ T0 is a reference time delay difference (also referred to as flow meter zero or system zero) in a condition of zero flow under a predetermined environment. Due to phase difference
And
are all the drive signals S0, so the phase difference between the first channel output signal Scha and the second channel output signal Schb can be used
To calculate the first time delay difference at (i.e.,
) Wherein, in the step (A),
outputting the phase of the signal Scha for the first channel
Phase with the second channel output signal Schb
The difference of (a).
Through research, the inventor believes that the confidence of the flow rate R' calculated by the method needs to be improved. Referring to equation 2, the first time delay Ta is the sum of the sensor time delay Ta _ sensor of the right sensor Sa and the time delay Ta _ channel of the first channel.
Ta＝Ta_sensor+Ta_channel (2)
Similarly, the second time delay Tb is the sum of the sensor time delay Tb _ sensor of the left sensor Sb and the time delay Tb _ channel of the second channel, see equation 3.
Tb＝Tb_sensor+Tb_channel (3)
And the first time delay difference at is defined as shown in equation 4.
Δt＝Ta-Tb (4)
It can be seen that, as shown in equation 5, the first time delay difference Δ t is the sum of the current sensor time delay difference Δ t _ sensor and the current channel time delay difference Δ t _ channel.
Δt＝Δt_sensor+Δt_channel (5)
Wherein, Δ t _ sensor ═ Ta _ sensor-Tb _ sensor, Δ t _ channel ═ Ta _ channel-Tb _ channel.
The exact current flow rate R is determined using equation 6, in accordance with the principles of the coriolis flow meter.
R＝FCF*(Δt_sensor-ΔT0_sensor) (6)
Where Δ T0_ sensor is the sensor reference time delay difference (also referred to as sensor zero or mechanical zero) under a condition of a predetermined environment and zero flow.
From this, R' ═ R + FCF (Δ T _ channel- Δ T0_ channel), where Δ T _ channel is the current channel time delay difference, Δ T0_ channel is the channel reference time delay difference (also referred to as channel zero, electronic zero, or transmitter zero) at the predetermined environmental conditions, and Δ T0 ═ Δ T0_ sensor + Δ T0_ channel. Since the environmental conditions (e.g., temperature, relative humidity, etc.) at the current flow may differ from the predetermined environmental conditions, (Δ T _ channel- Δ T0_ channel) is not necessarily zero. Therefore, the confidence of the current flow rate calculated in the comparative example is to be improved. The predetermined environmental condition may refer to an environmental condition at a predetermined temperature and relative humidity, such as: ambient conditions of 20 ℃ temperature and 50% relative humidity. Preferably, the predetermined environmental conditions are selected to be the environmental conditions at the typical operating conditions at which the flow meter is actually used. When the flow measurement is not sensitive to humidity, the predetermined environmental condition may refer to an environmental condition at a predetermined temperature, such as: the temperature is 20 deg.C. Since the channel reference time delay difference Δ T0_ channel is independent of traffic, the environmental condition should be the predetermined environmental condition when determining Δ T0_ channel, but the traffic may be zero or some non-zero value.
In view of the above, the inventors have devised the following various transmitters for a coriolis flowmeter.
In summary, the above-described transmitter for a coriolis flowmeter comprises: a first channel having a first operational amplifier and configured to output a first channel output signal; a second channel having a second operational amplifier and configured to output a second channel output signal; a signal processor configured to receive the first channel output signal and the second channel output signal and to determine a time delay difference between the first channel output signal and the second channel output signal; and a switching unit comprising at least one switching pair and configured to switch an input signal pair of at least one of the first channel and the second channel between two input signal pairs by switching the switching unit between a first electrical connection state and a second electrical connection state, such that the signal processor is able to determine a current channel time delay difference and a current flow rate of the transmitter; wherein the signal processor is further configured to output a switch control signal to control an electrical connection state of the switching unit; the signal sources of the two input signal pairs are different from each other; the first channel is configured to receive a first differential signal pair output from the right pickoff during vibration of a measurement tube of a coriolis flow meter driven by a driver of the coriolis flow meter with a drive signal; and the second channel is configured to receive a second differential signal pair output from the left sensor during vibration of the measurement tube of the coriolis flow meter driven by the driver of the coriolis flow meter with the drive signal.
Fig. 3 is a schematic diagram of the structure of a coriolis flow meter 10A according to an embodiment of the present disclosure. Fig. 4a is a schematic diagram showing the circuit configuration of coriolis flow meter 10A in fig. 3. Fig. 4b shows a block diagram of the circuit configuration of coriolis flow meter 10A in fig. 4 a.
As shown in fig. 3, coriolis flow meter 10A includes: transmitter 105A, measurement pipe 103, driver D, right sensor Sa, and left sensor Sb. The measurement pipe 103 is configured with a pair of pipes arranged in parallel, i.e., a first measurement pipe 103a and a second measurement pipe 103 b. The pipe is for example a U-shaped pipe. A driver D is mounted on the measurement pipe 103 and configured to drive the measurement pipe 103 into vibration with a drive signal S0. The right sensor Sa is mounted on the measurement pipe 103, and is configured to output a first differential signal pair Pa consisting of signals Sa1 and Sa 2. The left sensor Sb is mounted on the measurement pipe 103, and the left sensor Sb is configured to output a second differential signal pair Pb consisting of signals Sb1 and Sb 2. Specifically, for example, the left sensor Sb is mounted on the measurement pipe on the inlet side, and the right sensor Sa is mounted on the measurement pipe on the outlet side. That is, coriolis flow meter 10A in fig. 3 is changed from coriolis flow meter 10' in fig. 1 in that: a new transmitter 105A is used. The remaining components of coriolis flow meter 10A may be the same as the corresponding components of coriolis flow meter 10' and will not be described further herein.
The structure of transmitter 105A and coriolis flowmeter 10A will be described below with reference to fig. 4. Transmitter 105A includes: switching unit 1 comprising a first switching pair Psw1 and a second switching pair Psw209. A first path Cha, a second path Chb and a signal processor SP. The first switch pair Psw1 includes switches Sw11 and Sw 12. The second switch pair Psw2 includes switches Sw21 and Sw 22. The first switch pair Psw1 has a first switch input pair Pis1 consisting of input terminals Is11 and Is 12. The first switch input terminal pair Pis1 is for receiving the first differential signal pair Pa. The second switch pair Psw2 has a second switch input pair Pis2 consisting of input terminals Is21 and Is 22. The second switch input pair Pis2 is for receiving a second differential signal pair Pb. The first channel Cha includes a first channel input end pair Pc1 consisting of input terminals C11 and C12, and a third channel input end pair Pc3 consisting of input terminals C31 and C32. The second channel Chb includes a second channel input end pair Pc2 consisting of input terminals C21 and C22, and a fourth channel input end pair Pc4 consisting of input terminals C41 and C42. Note that in operation of coriolis flow meter 10A, right sensor output terminal pair Ps1 Is electrically connected to first switch input terminal pair Pis1 (i.e., S11 Is11 electrically, and S12 Is12 electrically) to receive first differential signal pair Pa; the left pair of sensor output terminals Ps2 Is electrically connected to the second pair of switch input terminals Pis2 (i.e., S21 Is21 electrically and S22 Is22 electrically) to receive the second differential signal pair Pb. The first channel Cha has leads, an operational amplifier OA1, resistors R1, R2, R3, and a capacitor C1. The second channel Chb has leads, an operational amplifier OA2, resistors R5, R6, R7, and a capacitor C2. The signal processor SP in fig. 4a is capable of outputting a driver control signal Sc that controls the driver D to vibrate the measurement tube of the coriolis flow meter 10A with a drive signal S0. The right sensor Sa is configured to sense vibration of the measurement pipe on the outlet side, and to give a first differential signal pair Pa composed of signals Sa1 and Sa2 in relation to the vibration, where the first differential signal pair Pa is a signal pair output from the right sensor Sa during vibration of the measurement pipe 103 of the coriolis flow meter 10A driven by the driver D of the coriolis flow meter 10A with the drive signal S0. The first differential signal pair Pa is output via a right sensor output terminal pair Ps1, wherein the right sensor output terminal pair Ps1 is composed of output terminals S11 and S12. The left sensor Sb is configured to sense vibration of the measurement pipe on the inlet side and give a signal related to the vibrationSb1 and Sb2, wherein the second differential signal pair Pb is the signal pair output from the left sensor Sb during vibration of the measurement tube 103 of the coriolis flow meter 10A driven by the driver D of the coriolis flow meter 10A with the drive signal S0. The second differential signal pair Pb is output via the left sensor output terminal pair Ps2, wherein the left sensor output terminal pair Ps2 is composed of output terminals S21 and S22. The signal processor SP is configured to receive the first channel output signal Scha and the second channel output signal Schb and to determine a time delay difference between a first time delay Ta of the first channel output signal relative to the drive signal S0 and a second time delay Tb of the second channel output signal relative to the drive signal S0. The time delay difference may be determined by using the difference between Ta and Tb directly after Ta and Tb are determined, or may be determined by the phase difference between the first channel output signal Scha and the second channel output signal Schb as in the comparative example
To calculate the time delay difference (i.e., the time delay difference is equal to
) Wherein, in the step (A),
the phase difference may be determined directly from the difference between the phase of the first channel output signal Scha and the phase of the second channel output signal Schb, or a first phase difference of the first channel output signal Scha with respect to the driving signal S0 and a second phase difference of the second channel output signal Schb with respect to the driving signal S0 may be determined first, and then the phase difference may be determined based on the first phase difference and the second phase difference
The electrical connection states of the switch unit 109 (i.e., the first and second switch pairs Psw1 and Psw2) include a first electrical connection state St1 and a second electrical connection state St 2. As shown in fig. 4a and 4b, the signal processor SP is further configured to output a switch control signal Ssw to control the electrical connection state of the switch unit 109.Under the action of the switching control signal Ssw, the switching unit 109 can be controllably brought into one of the first electrical connection state st1 and the second electrical connection state st 2.
For the transmitter 105A, in the first electrical connection state St1, the first switch pair Psw1 electrically connects the first switch input pair Pis1 with the first channel input pair Pc1 of the first channel Cha (i.e., Is11 electrically connects C11, Is12 electrically connects C12), and the second switch pair Psw2 electrically connects the second switch input pair Pis2 with the second channel input pair Pc2 of the second channel Chb (i.e., Is21 electrically connects C21, Is22 electrically connects C22).
For transmitter 105A, in the second electrical connection state St2, the first switch pair Psw1 electrically connects the first switch input pair Pis1 with the fourth channel input pair Pc4 (i.e., Is11 electrically connects C41, Is12 electrically connects C42), and the second switch pair Psw2 electrically connects the second switch input pair Pis2 with the third channel input pair Pc3 (i.e., Is21 electrically connects C31, Is22 electrically connects C32).
Referring to fig. 4a and 4b, the input signal pair of the first channel Cha is switchable between two input signal pairs (i.e., a first differential signal pair Pa from the right sensor Sa and a second differential signal pair Pb from the left sensor Sb) via the switching unit 109; the input signal pair of the second channel Chb is switchable between two input signal pairs (i.e., the first differential signal pair Pa from the right sensor Sa and the second differential signal pair Pb from the left sensor Sb) via the switching unit 109.
Preferably, the leads used in the first channel Cha and the second channel Chb have a shield layer that is grounded. The signal processor SP may be a digital signal processor or an analog signal processor. In the case that the signal processor SP is a digital signal processor, the first channel Cha and the second channel Chb may further be provided with analog-to-digital converters. It should be noted that, in the present disclosure, the components included in the first channel Cha and the second channel Chb are not limited to the components shown in fig. 4a, and may be added, reduced and/or replaced as needed.
In the first electrical connection state St1, see equation 2, the first time delay Ta is the sum of the sensor time delay Ta _ sensor of the right sensor Sa and the time delay Ta _ channel of the first channel; referring to equation 3, the second time delay Tb is the sum of the sensor time delay Tb _ sensor of the left sensor Sb and the time delay Tb _ channel of the second channel.
In the second electrical connection state St2, see equation 7, the third time delay Ta' is the sum of the sensor time delay Tb _ sensor of the left sensor Sb and the time delay Ta _ channel of the first channel; referring to equation 8, the fourth time delay Tb' is the sum of the sensor time delay Ta _ sensor of the right sensor Sa and the time delay Tb _ channel of the second channel.
Ta'＝Tb_sensor+Ta_channel (7)
Tb'＝Ta_sensor+Tb_channel (8)
As can be seen from equations 2, 3, 7, and 8, the current channel time delay difference Δ t _ channel can be calculated by using equation 9.
The current sensor time delay difference Δ t _ sensor can be calculated using equation 10.
Wherein the first time delay difference Δ t ═ Ta _ sensor-Tb _ sensor) + (Ta _ channel-Tb _ channel); the second time delay difference Δ t ═ Tb _ sensor-Ta _ sensor) + (Ta _ channel-Tb _ channel).
In the condition of the predetermined environment and the zero flow rate, the signal processor SP may determine the sensor reference time delay difference Δ T0_ sensor and the channel reference time delay difference Δ T0_ channel in the condition of the predetermined environment and the zero flow rate using equations 9 and 10. Note that if only the channel reference time delay difference Δ T0_ channel needs to be determined, it does not need to be done at zero traffic, but can be done at any traffic and the ambient conditions are predetermined ambient conditions.
In this way, the signal processor can more accurately determine the current flow rate R using equation 6, where Δ T0_ sensor (i.e., sensor zero), Δ T0_ channel (i.e., channel zero or transmitter zero) can be predetermined and stored in a memory device of transmitter 105 for later use. If necessary, the sensor zero point and/or the channel zero point can also be determined anew in order to update the stored sensor zero point and/or channel zero point.
The signal processor SP may be configured to control the switching unit 109 to be periodically in the first and second electrical connection states St1 and St2, and the first and second electrical connection states St1 and St2 are temporally adjacent to each other, so that the current channel time delay difference and the current sensor time delay difference can be dynamically determined in real time according to equations 9 and 10.
The signal processor SP can also accurately determine the current flow rate R using equation 11.
R＝FCF*(Δt-ΔT0)-FCF*(Δt_channel-ΔT0_channel) (11)
Since the current channel time delay difference is related to the environmental conditions in which the channel is located, the historical channel time delay difference Δ th _ channel may be used instead of Δ t _ channel in equation 11 when the environmental conditions are more stable, for example, the channel time delay difference determined by equation 9 by switching the electrical connection state before 10 minutes (i.e., the historical channel time delay difference Δ th _ channel); preferably, the previous environmental conditions and the current environmental conditions are close or different to within a predetermined range. That is, the determined channel time delay differential for a historical time can be stored in the memory device of transmitter 105 as a historical channel time delay differential for later multiple use. It can be seen that the signal processor SP can also accurately determine the current flow rate R using equation 12.
R＝FCF*(Δt-ΔT0)-FCF*(Δth_channel-ΔT0_channel) (12)
Since the channel time delay difference does not necessarily need to be determined each time when the current flow rate is determined, the signal processor SP may be further configured to control the switch unit 109 to be in the first electrical connection state St1 for a consecutive plurality of switch-on periods after being in the second electrical connection state St 2.
As shown in fig. 5a and 5B, coriolis flowmeter 10B includes a transmitter 105B. The structure of coriolis flowmeter 10B is the same as coriolis flowmeter 10A except for the transmitter. The structures of transmitter 105B and coriolis flowmeter 10B are described below with reference to fig. 5a and 5B. Transmitter 105B includes: a switching unit 109 comprising a first switch pair Psw1 and a second switch pair Psw2, a first channel Cha, a second channel Chb, a signal processor SP and a reference signal source 110. The first switch pair Psw1 includes switches Sw11 and Sw 12. The second switch pair Psw2 includes switches Sw21 and Sw 22. The first switch pair Psw1 has a first switch input pair Pis1 consisting of input terminals Is11 and Is 12. The first switch input terminal pair Pis1 is for receiving the first differential signal pair Pa. The second switch pair Psw2 has a second switch input pair Pis2 consisting of input terminals Is21 and Is 22. The second switch input pair Pis2 is for receiving a second differential signal pair Pb. The first channel Cha includes a first channel input end pair Pc1 consisting of input terminals C11 and C12. The second channel Chb includes a second channel input pair Pc2 consisting of input terminals C21 and C22. Note that, during operation of coriolis flow meter 10B, right sensor output terminal pair Ps1 Is electrically connected to first switch input terminal pair Pis1 (i.e., S11 Is11 electrically, and S12 Is12 electrically) to receive first differential signal pair Pa; the left pair of sensor output terminals Ps2 Is electrically connected to the second pair of switch input terminals Pis2 (i.e., S21 Is21 electrically and S22 Is22 electrically) to receive the second differential signal pair Pb. The first channel Cha has leads, an operational amplifier OA1, resistors R1, R2, R3, and a capacitor C1. The second channel Chb has leads, an operational amplifier OA2, resistors R5, R6, R7, and a capacitor C2. The signal processor SP in fig. 5a is capable of outputting a driver control signal Sc that controls the driver D to vibrate the measurement tube of the coriolis flow meter 10B with a drive signal S0. The driver control signal Sc can also control the reference signal source 110 to output the first reference differenceA signal pair Psr1 and a second reference differential signal pair Psr2, wherein the first reference differential signal pair Psr1 consists of signals Sr11 and Sr12, and the second reference differential signal pair Psr2 consists of signals Sr21 and Sr 22. The reference signal source 110 has a first reference differential signal output pair Pr1 and a second reference differential signal output pair Pr2, where the first reference differential signal output pair Pr1 is composed of output terminals r11 and r12, and the second reference differential signal output pair Pr2 is composed of output terminals r21 and r 22. The reference signal source 110 is configured to output a first reference differential signal pair Psr1 from a first reference differential signal output terminal Pr1 pair, and output a second reference differential signal pair Psr2 from a second reference differential signal output terminal pair Pr 2. The frequency of each of the first and second reference differential signal pairs Psr1 and Psr2 is the same as the frequency of the drive signal S0. The phases of the positive phase signals (Sr12, Sr22) in the first reference differential signal pair Psr1 and the second reference differential signal pair Psr2 are the same, and the phases of the negative phase signals (Sr11, Sr21) in the first reference differential signal pair Psr1 and the second reference differential signal pair Psr2 are also the same. That is, the first reference differential signal pair Psr1 and the second reference differential signal pair Psr2 are the same differential signal pair. The reference signal source 110 may be a driving signal distributor that converts the driving signal S0 into a reference differential signal pair and distributes the reference differential signal pair to the first reference differential signal output pair Pr1 and the second reference differential signal output pair Pr2, or a sine wave generator. The right sensor Sa is configured to sense vibration of the measurement pipe on the outlet side, and to give a first differential signal pair Pa composed of signals Sa1 and Sa2 in relation to the vibration, where the first differential signal pair Pa is a signal pair output from the right sensor Sa during vibration of the measurement pipe of the coriolis flow meter 10B driven by the driver D of the coriolis flow meter 10B with the drive signal S0. The first differential signal pair Pa is output via a right sensor output terminal pair Ps1, wherein the right sensor output terminal pair Ps1 is composed of output terminals S11 and S12. The left sensor Sb is configured to sense vibrations of the measurement tube on the inlet side and to provide a second differential signal pair Pb of signals Sb1 and Sb2 related to the vibrations, wherein the second differential signal pair Pb is driven at the driver D of the coriolis flowmeter 10B with a drive signal S0The pair of signals output from the left sensor Sb during the vibration of the measurement pipe of the dynamic coriolis flowmeter 10B. The second differential signal pair Pb is output via the left sensor output terminal pair Ps2, wherein the left sensor output terminal pair Ps2 is composed of output terminals S21 and S22. The signal processor SP is configured to receive the first channel output signal Scha and the second channel output signal Schb and to determine a time delay difference between a first time delay Ta of the first channel output signal Scha relative to the drive signal S0 and a second time delay Tb of the second channel output signal relative to the drive signal S0. The time delay difference may be determined by using the difference between Ta and Tb directly after Ta and Tb are determined, or may be determined by the phase difference between the first channel output signal Scha and the second channel output signal Schb as in the comparative example
To calculate the time delay difference (i.e., the time delay difference is equal to
) Wherein, in the step (A),
the phase difference may be determined directly from the difference between the phase of the first channel output signal Scha and the phase of the second channel output signal Schb, or a first phase difference of the first channel output signal Scha with respect to the driving signal S0 and a second phase difference of the second channel output signal Schb with respect to the driving signal S0 may be determined first, and then the phase difference may be determined based on the first phase difference and the second phase difference
The electrical connection states of the switch unit 109 (the first switch pair Psw1 and the second switch pair Psw2) include a first electrical connection state St1 and a second electrical connection state St 2. As shown in fig. 5a and 5b, the signal processor SP is further configured to output a switch control signal Ssw to control the electrical connection state of the switch unit 109. Under the action of the switch control signal Ssw, the switch unit 109 may be controllably brought into one of the first electrical connection state St1 and the second electrical connection state St 2.
For the transmitter 105B, in the first electrical connection state St1, the first switch pair Psw1 electrically connects the first switch input terminal pair Pis1 with the first channel input terminal pair Pc1 of the first channel Cha (i.e., Is11 electrically connects C11 and Is12 electrically connects C12), and the second switch pair Psw2 electrically connects the second switch input terminal pair Pc2 with the second channel input terminal pair Pc2 of the second channel Chb (i.e., Is21 electrically connects C21 and Is22 electrically connects C22). Based on the first channel output signal Scha and the first channel output signal Schb in the first state St1, the signal processor SP is able to determine the first time delay difference Δ t at the current flow rate.
For the transmitter 105B, in the second electrical connection state St2, the first switch pair Psw1 electrically connects the first reference differential signal output pair Pr1 with the first channel input pair Pc1 (i.e., r11 electrically connects C11, and r12 electrically connects C12), and the second switch pair Psw2 electrically connects the second reference differential signal output pair Pr2 with the second channel input pair Pc2 (i.e., r21 electrically connects C21, and r22 electrically connects C22). Based on the first channel output signal Scha and the first channel output signal Schb in the second state St2, the signal processor SP is able to determine the second time delay difference Δ t' for the current flow situation. Since the same reference differential signal pair is input to both channels in the second electrical connection state St2, the current channel time delay difference Δ t _ channel is equal to the second time delay difference Δ t'. Accordingly, the current sensor time delay difference Δ t _ sensor ═ Δ t- Δ t'. As can be seen, when the switching unit 109 is set to the second electrical connection state St2, the current channel time delay difference Δ t _ channel may be determined. The signal processor SP is configured to set the second time delay difference Δ t' to the current channel time delay difference Δ t _ channel between the first channel and the second channel Chb.
Referring to fig. 5a and 5b, the input signal pair of the first channel Cha is switchable between two input signal pairs (i.e. the first differential signal pair Pa from the right sensor Sa and the first reference differential signal pair Psr1 from the reference signal source 110) via the switching unit 109; the input signal pair of the second channel Chb can be switched between two input signal pairs (i.e., the second differential signal pair Pb from the left sensor Sb and the second reference differential signal pair Psr2 from the reference signal source 110) via the switching unit 109.
If the switching unit 109 of the coriolis flowmeter 10B is switched between the first electrical connection state St1 and the second electrical connection state St2 under the condition of the predetermined environment and the flow rate being zero, the sensor reference time delay difference Δ T0_ sensor, the channel reference time delay difference Δ T0_ channel, and the reference time delay difference Δ T0 ═ Δ T0_ sensor + Δ T0_ channel under the condition of the predetermined environment and the flow rate being zero can be determined. Note that if only the channel reference time delay difference Δ T0_ channel needs to be determined, it does not need to be done at zero traffic, but can be done at any traffic and the ambient conditions are predetermined ambient conditions.
With the above time delay differential, the current flow rate R can be determined using equations 6, 11, and 12 as well, using coriolis flow meter 10B. Note that for coriolis flow meter 10B, the flow condition need not be considered in determining the current channel time delay difference Δ t _ channel. If the flow is unstable, the current channel time delay difference Δ t _ channel can still be accurately determined.
For the transmitter 105C, in the first electrical connection state St1, the second switch pair Psw2 electrically connects the second switch input pair Pis2 with the second channel input pair Pc2 of the second channel Chb (i.e., Is21 electrically connects C21, and Is22 electrically connects C22) to receive the second differential signal pair Pb. Based on the first channel output signal Scha and the first channel output signal Schb in the first state St1, the signal processor SP is able to determine the first time delay difference Δ t at the current flow rate.
For transmitter 105C, in the second electrical connection state St2, the second switch pair Psw2 electrically connects the fourth switch input pair Pis4 with the second channel input pair Pc2 (i.e., Is41 electrically connects C21 and Is42 electrically connects C22). Based on the first channel output signal Scha and the first channel output signal Schb in the second state St2, the signal processor SP is able to determine the second time delay difference Δ t' for the current flow situation. Since the same first differential signal pair Pa is input to both channels in the second electrical connection state St2, the current channel time delay difference Δ t _ channel is equal to the second time delay difference Δ t'. Accordingly, the current sensor time delay difference Δ t _ sensor ═ Δ t- Δ t'. As can be seen, when the switching unit 109 is set to the second electrical connection state St2, the current channel time delay difference Δ t _ channel may be determined. The signal processor SP is configured to set the second time delay difference Δ t' to the current channel time delay difference Δ t _ channel between the first channel and the second channel Chb.
Referring to fig. 6a and 6b, the input signal pair of the second channel Chb can be switched between two input signal pairs (i.e., the second differential signal pair Pb from the left sensor Sb and the first differential signal pair Pa from the right sensor Sa) via the switching unit 109.
If the switching unit 109 of the coriolis flowmeter 10C is switched between the first electrical connection state St1 and the second electrical connection state St2 under the condition of the predetermined environment and the flow rate being zero, the sensor reference time delay difference Δ T0_ sensor, the channel reference time delay difference Δ T0_ channel, and the reference time delay difference Δ T0 ═ Δ T0_ sensor + Δ T0_ channel under the condition of the predetermined environment and the flow rate being zero can be determined. Note that if only the channel reference time delay difference Δ T0_ channel needs to be determined, it does not need to be done at zero traffic, but can be done at any traffic and the ambient conditions are predetermined ambient conditions.
With the above time delay differential, the coriolis flow meter 10C is used and the current flow rate R can be determined using equations 6, 11, and 12 as well. Note that for coriolis flow meter 10C, the flow condition need not be considered in determining the current channel time delay difference Δ t _ channel. If the flow is unstable, the current channel time delay difference Δ t _ channel can still be accurately determined.
For the transmitter 105D, in the first electrical connection state St1, the first switch pair Psw1 electrically connects the first switch input pair Pis1 with the first channel input pair Pc1 of the first channel Cha (i.e., Is11 electrically connects C11 and Is12 electrically connects C12) to receive the first differential signal pair Pa. Based on the first channel output signal Scha and the first channel output signal Schb in the first state St1, the signal processor SP is able to determine the first time delay difference Δ t at the current flow rate.
For the transmitter 105D, in the second electrical connection state St2, the first switch pair Psw1 electrically connects the third switch input pair Pis3 with the first channel input pair Pc1 (i.e., Is31 electrically connects C11 and Is32 electrically connects C32). Based on the first channel output signal Scha and the first channel output signal Schb in the second state St2, the signal processor SP is able to determine the second time delay difference Δ t' for the current flow situation. Since the same second differential signal pair Pb is input to both channels in the second electrical connection state St2, the current channel time delay difference Δ t _ channel is equal to the second time delay difference Δ t'. Accordingly, the current sensor time delay difference Δ t _ sensor ═ Δ t- Δ t'. As can be seen, when the switching unit 109 is set to the second electrical connection state, the current channel time delay difference Δ t _ channel may be determined. The signal processor SP is configured to set the second time delay difference Δ t' to the current channel time delay difference Δ t _ channel between the first channel and the second channel Chb.
Referring to fig. 7a and 7b, the input signal pair of the first channel Cha is switchable between two input signal pairs (i.e., a first differential signal pair Pa from the right sensor Sa and a second differential signal pair Pb from the left sensor Sb) via the switching unit 109.
If the switching unit 109 of the coriolis flowmeter 10D is switched between the first electrical connection state St1 and the second electrical connection state St2 under the condition of the predetermined environment and the flow rate being zero, the sensor reference time delay difference Δ T0_ sensor, the channel reference time delay difference Δ T0_ channel, and the reference time delay difference Δ T0 ═ Δ T0_ sensor + Δ T0_ channel under the condition of the predetermined environment and the flow rate being zero can be determined. Note that if only the channel reference time delay difference Δ T0_ channel needs to be determined, it does not need to be done at zero traffic, but can be done at any traffic and the ambient conditions are predetermined ambient conditions.
With the above time delay differential, the current flow rate R can likewise be determined using equations 6, 11, 12 using coriolis flow meter 10D. Note that for coriolis flow meter 10D, the flow condition need not be considered in determining the current channel time delay difference Δ t _ channel. If the flow is unstable, the current channel time delay difference Δ t _ channel can still be accurately determined.
When determining the current flow rate using the coriolis flow meter 10A, 10B, 10C, or 10D using the formula 12, since Δ th _ channel can be used for a plurality of switch-on periods C, the signal processor SP may be configured to control the switch unit 109 to be in the first electrical connection state St1 after being in the second electrical connection state St2 for a consecutive plurality of switch-on periods, that is, the switching of the electrical connection state has a non-periodicity. Fig. 8 is a schematic diagram illustrating a non-periodic switching control signal Ssw according to an embodiment of the present disclosure. The aperiodic switch control signal in fig. 8 is suitable for the case where the environmental conditions are constant or vary slowly. The switch control signal Ssw controls the electrical connection state of the switch unit 109. For example, at the first level V1, the electrical connection state is the first state St1, and at the second level V2, the electrical connection state is the first state St 2. In FIG. 8, t is time, and Cn-2, Cn-1, Cn +1, and Cn +2 are the on periods of the n-2, n-1, n +1, and n +2 th switches, respectively. In fig. 8, the switch unit 109 is in the first electrical connection state St1 for a consecutive plurality of switch-on periods (e.g., switch-on periods Cn +1, Cn +2) after being in the second electrical connection state St 2. In the present disclosure, the switch-on period is related to the processing capacity of the signal processor, and the time of one switch-on period should be equal to or longer than the time taken to process the channel output signals Scha and Schb and determine the current flow rate.
When the current flow rate is determined using the coriolis flow meter 10A, 10B, 10C, or 10D, the switch unit 109 may be controlled to be periodically in the first electrical connection state St1 and the second electrical connection state St2, the first electrical connection state St1 and the second electrical connection state St2 being temporally adjacent to each other. Fig. 9 is a diagram showing the periodic switch control signal Ssw according to the embodiment of the present modification. The periodic switch control signal of fig. 9 is suitable for situations where environmental conditions change rapidly or where high flow measurement accuracy is required. The switch control signal Ssw controls the electrical connection state of the switch unit 109. At the first level V1, the electrical connection state is the first state St1, and at the second level V2, the electrical connection state is the first state St 2. In FIG. 9, t is time, and Cn-2, Cn-1, Cn +1, and Cn +2 are the on periods of the n-2, n-1, n +1, and n +2 th switches, respectively. As is apparent from fig. 9, in the present embodiment, the first electrical connection state St1 and the second electrical connection state St2 are temporally adjacent to each other.
Fig. 10 is a graph showing the change in the reference time delay difference (zero point) at different temperatures, wherein the flow meter used is the coriolis flow meter 10A. As shown in fig. 10, in the zero flow condition, when the ambient temperature Temp changes from 23 ℃ to 100 ℃, the sensor reference time delay difference Δ T0_ sensor changes by 0.1nS (i.e., the zero point of the sensor drifts by 0.1nS), the channel reference time delay difference Δ T0_ channel changes by 12.1nS (i.e., the zero point of the channel drifts by 12.1nS), and the flow meter reference time delay difference Δ T0 changes by 12.2nS (i.e., the zero point of the flow meter drifts by 12.2 nS). It can be seen that, by using the switching unit, the influence of the channel time delay difference change (channel zero drift) on the flow measurement can be eliminated, thereby improving the confidence of the flow measurement. In the example shown in fig. 10, flow measurement error may be reduced from "FCF 12.2 nS" to "FCF 0.1 nS" by using the flow meter described in the present disclosure.
With the solution disclosed in the present disclosure, by separating the contributions of the sensor and the channel to the time delay, the channel-induced zero drift can be removed, thereby improving the confidence of the measurement. With the disclosed aspects, by comparing the factory zero point of the sensor (i.e., the sensor reference time delay differential given by the flowmeter manufacturer) with the operating condition zero point of the sensor (i.e., the sensor reference time delay differential determined after actual installation), the installation stress of the sensor under operating conditions can be determined, thereby facilitating a determination of whether the installation is acceptable. With the coriolis flow meter disclosed in this disclosure, by tracking the recorded channel zero (i.e., channel reference time delay difference), a diagnosis of the health of the transmitter can be made before a catastrophic failure of the transmitter occurs to facilitate timely maintenance. With the coriolis flow meter disclosed in this disclosure, since it can be switched between the first electrical connection state and the second electrical connection state, the measurement performance of the flow meter can be ensured even under variable, harsh environments. The aforementioned functions of determining mounting stress, diagnosing the health of the transmitter, can be integrated into the transmitter, which aids in the intelligence of the gauge.
While the disclosure has been disclosed by the description of the specific embodiments thereof, it will be appreciated that those skilled in the art will be able to devise various modifications, improvements, or equivalents of the disclosure within the spirit and scope of the appended claims. Such modifications, improvements and equivalents are also intended to be included within the scope of the present disclosure.
It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, elements or components, but does not preclude the presence or addition of one or more other features, elements or components.
Claims (18)
1. A transmitter for a coriolis flowmeter, comprising:
a first channel having a first operational amplifier and configured to output a first channel output signal;
a second channel having a second operational amplifier and configured to output a second channel output signal;
a signal processor configured to receive the first channel output signal and the second channel output signal and to determine a time delay difference between the first channel output signal and the second channel output signal; and
a switching unit comprising at least one switching pair and configured to switch an input signal pair of at least one of the first channel and the second channel between two input signal pairs by switching the switching unit between a first electrical connection state and a second electrical connection state, such that the signal processor is able to determine a current channel time delay difference and a current flow rate of the transmitter;
wherein the signal processor is further configured to output a switch control signal to control an electrical connection state of the switching unit;
the signal sources of the two input signal pairs are different from each other;
the first channel is configured to receive a first differential signal pair output from a right sensor during vibration of a measurement tube of the coriolis flow meter driven by a driver of the coriolis flow meter with a drive signal;
the second channel is configured to receive a second differential signal pair output from a left sensor during vibration of a measurement tube of the coriolis flow meter driven by a driver of the coriolis flow meter with the drive signal;
the right sensor is a sensor positioned on the outlet side of the measuring pipe; and is
The left sensor is a sensor located on the inlet side of the measurement pipe.
2. The transmitter of claim 1, wherein the switching unit comprises a first switch pair and a second switch pair;
the first channel comprises a first channel input end pair and a third channel input end pair;
the second channel comprises a second channel input end pair and a fourth channel input end pair;
the first switch pair has a first pair of switch inputs for receiving the first differential signal pair;
the second switch pair has a second pair of switch inputs for receiving the second differential signal pair; and is
The switching unit is configured to:
in the first electrical connection state, the first switch pair electrically connects the first switch input pair with the first channel input pair, and the second switch pair electrically connects the second switch input pair with the second channel input pair; and is
In the second electrical connection state, the first switch pair electrically connects the first switch input pair with the fourth channel input pair, and the second switch pair electrically connects the second switch input pair with the third channel input pair.
3. The transmitter of claim 1, further comprising a reference signal source;
the reference signal source is provided with a first reference differential signal output end pair and a second reference differential signal output end pair;
the reference signal source is configured to output a first reference differential signal pair from the first reference differential signal output pair and a second reference differential signal pair from the second reference differential signal output pair;
the frequency of each of the first and second reference differential signal pairs is the same as the frequency of the drive signal;
the phases of the positive phase signals in the first reference differential signal pair and the second reference differential signal pair are the same;
the switching unit includes a first switching pair and a second switching pair;
the first switch pair has a first pair of switch inputs for receiving a first differential signal pair;
the second switch pair has a second switch input pair for receiving a second differential signal pair; and is
The switching unit is configured to:
in the first electrical connection state, the first switch pair electrically connects the first switch input pair with a first channel input pair of the first channel, and the second switch pair electrically connects the second switch input pair with a second channel input pair of the second channel; and is
In the second electrical connection state, the first switch pair electrically connects the first reference differential signal output pair with the first channel input pair, and the second switch pair electrically connects the second reference differential signal output pair with the second channel input pair.
4. The transmitter of claim 1, wherein the switching unit comprises a second pair of switches;
the first lane has a first pair of lane inputs for receiving the first differential signal pair;
the second switch pair has a second switch input pair for receiving a second differential signal pair and a fourth switch input pair connected in parallel with the first channel input pair; and is
The switching unit is configured to:
in the first electrical connection state, the second switch pair electrically connects the second switch input pair with a second channel input pair of the second channel; and is
In the second electrical connection state, the second switch pair electrically connects the fourth switch input pair with the second channel input pair.
5. The transmitter of claim 1, wherein the switching unit comprises a first pair of switches;
the second channel has a second pair of channel inputs for receiving the second differential signal pair;
the first switch pair has a first switch input pair for receiving a first differential signal pair and a third switch input pair connected in parallel with the second channel input pair; and is
The switching unit is configured to:
in the first electrical connection state, the first switch pair electrically connects the first switch input pair with a first channel input pair of the first channel to receive the first differential signal pair; and is
In the second electrical connection state, the first switch pair electrically connects the third switch input pair with the first channel input pair.
6. The transmitter of one of claims 2 to 5, wherein determining a time delay differential between the first channel output signal and the second channel output signal comprises determining a first time delay differential corresponding to the first electrical connection state and determining a second time delay differential corresponding to the second electrical connection state.
7. The transmitter of claim 6, wherein the signal processor is configured to determine a current sensor time delay differential between the right sensor and the left sensor based on the first time delay differential and the second time delay differential.
8. The transmitter of claim 7, wherein the signal processor is configured to control the switching unit to be periodically in the first and second electrical connection states, and the first and second electrical connection states are temporally adjacent to each other.
9. The transmitter of claim 8, wherein the signal processor is configured to determine the current flow rate by:
R＝FCF*(Δt_sensor-ΔT0_sensor)，
where R is the current flow, FCF is a flow calibration factor, Δ T _ sensor is the current sensor time delay differential, and Δ T0_ sensor is the sensor reference time delay differential under conditions of predetermined environment and zero flow.
10. The transmitter of claim 2, wherein determining the time delay differential between the first channel output signal and the second channel output signal comprises determining a first time delay differential corresponding to the first electrical connection state and determining a second time delay differential corresponding to the second electrical connection state, and the signal processor is configured to determine the current channel time delay differential between the first channel and the second channel based on the first time delay differential and the second time delay differential.
11. The transmitter of claim 10, wherein the signal processor is configured to determine the current flow rate by the formula:
R＝FCF*(Δt-ΔT0)-FCF*(Δt_channel-ΔT0_channel)，
wherein R is the current flow, FCF is a flow calibration factor, Δ T is the first time delay difference, Δ T0 is a reference time delay difference under a condition of a predetermined environment and zero flow, Δ T _ channel is the current channel time delay difference, and Δ T0_ channel is the channel reference time delay difference under a condition of the predetermined environment.
12. The transmitter of one of claims 2 to 5, wherein the signal processor is configured to determine the current flow rate by the formula:
R＝FCF*(Δt-ΔT0)-FCF*(Δth_channel-ΔT0_channel)，
wherein R is the current flow, FCF is a flow calibration factor, Δ T is a first time delay difference corresponding to the time delay difference in the first electrical connection state, Δ T0 is a reference time delay difference under a condition of a predetermined environment and zero flow, Δ th _ channel is a history channel time delay difference, and Δ T0_ channel is a channel reference time delay difference under a condition of the predetermined environment.
13. The transmitter according to one of claims 2 to 5, wherein the signal processor is configured to control the switching unit to be in the first electrical connection state for a consecutive plurality of switch-on periods after being in the second electrical connection state.
14. The transmitter of claim 1, wherein the signal processor is configured to determine a phase difference between the first channel output signal and the second channel output signal to determine the time delay difference based on the phase difference.
15. The transmitter of claim 14, wherein the signal processor is configured to determine a first phase difference between the first channel output signal and the drive signal and a second phase difference between the second channel output signal and the drive signal to determine the phase difference based on the first phase difference and the second phase difference.
16. The transmitter of one of claims 3 to 5, wherein determining the time delay differential comprises determining a first time delay differential corresponding to the first electrical connection state and determining a second time delay differential corresponding to the second electrical connection state, and the signal processor is configured to set the second time delay differential to the current channel time delay differential between the first channel and the second channel.
17. The transmitter of claim 16, wherein the signal processor is configured to determine the current flow rate by the formula:
R＝FCF*(Δt-ΔT0)-FCF*(Δt_channel-ΔT0_channel)，
wherein R is the current flow, FCF is a flow calibration factor, Δ T is the first time delay difference, Δ T0 is a reference time delay difference under a condition of a predetermined environment and zero flow, Δ T _ channel is the current channel time delay difference, and Δ T0_ channel is the channel reference time delay difference under a condition of the predetermined environment.
18. A coriolis flow meter comprising:
the transmitter of one of claims 1 to 17;
the measuring tube;
the driver mounted on the measurement pipe and configured to drive the measurement pipe to vibrate with the drive signal;
the right sensor mounted on the measurement tube and configured to output the first differential signal pair; and
the left sensor mounted on the measurement tube and configured to output the second differential signal pair.
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| CN201810040074.6A CN110044431B (en) | 2018-01-16 | 2018-01-16 | Transmitter and flowmeter |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1189037A1 (en) * | 2000-09-13 | 2002-03-20 | Endress + Hauser Flowtec AG | Coriolis flowmeter with digital control system |
| DE102004055553A1 (en) * | 2004-11-17 | 2006-05-18 | Endress + Hauser Flowtec Ag | Measuring and operating circuit for a Coriolis mass flowmeter with three measuring channels |
| DE102005025354A1 (en) * | 2005-05-31 | 2006-12-07 | Endress + Hauser Flowtec Ag | Coriolis mass flow meter and method for compensation of transmission errors of its input circuit |
| WO2008109841A1 (en) * | 2007-03-07 | 2008-09-12 | Invensys Systems, Inc. | Coriolis frequency tracking |
| JP5098526B2 (en) * | 2007-09-05 | 2012-12-12 | 横河電機株式会社 | Coriolis mass flow meter |
| JP4694645B1 (en) * | 2010-02-19 | 2011-06-08 | 株式会社オーバル | Signal processing method, signal processing apparatus, and vibration type density meter |
| CN102506951B (en) * | 2011-10-28 | 2013-05-01 | 合肥工业大学 | Method and system of digital driving following for Coriolis mass flowmeter |
| DE102012215282B3 (en) * | 2012-08-29 | 2013-07-18 | Siemens Aktiengesellschaft | Coriolis mass flowmeter |
| CN103245386B (en) * | 2013-04-10 | 2015-03-04 | 温州新蓝科技有限公司 | Coriolis flowmeter and information processing technology thereof |
| CN103984228B (en) * | 2014-05-31 | 2017-02-01 | 福州大学 | Method for designing Coriolis mass flow meter digital drive system |
| CN105784036B (en) * | 2016-04-06 | 2018-10-02 | 合肥工业大学 | A kind of differential type power amplification circuit in Coriolis mass flowmeter drive system |
| CN206281537U (en) * | 2016-12-05 | 2017-06-27 | 高准有限公司 | The drive circuit and flowmeter of coil |
| CN208155378U (en) * | 2018-01-16 | 2018-11-27 | 高准有限公司 | transmitter and flowmeter |
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