Operating a vibratory meter in two or more vibration modes

Abstract

A method of operating a vibratory meter in two or more vibration modes is provided. The method comprises vibrating, with a drive signal, a sensor assembly in a first vibration mode and vibrating, with the drive signal, the sensor assembly in a second vibration mode, wherein nodes of the first vibration mode and nodes of the second vibration modes are symmetrically located on a conduit of the sensor assembly.

Description

[0001]OPERATING A VIBRATORY METER IN TWO OR MORE VIBRATION MODES TECHNICAL FIELD The embodiments described below relate to vibratory meter measurements and, more particularly, to operating a vibratory meter in two or more vibration modes. BACKGROUND Vibratory meters, such as for example, Coriolis mass flowmeters, liquid density meters, gas density meters, liquid viscosity meters, gas / liquid specific gravity meters, gas / liquid relative density meters, and gas molecular weight meters, are generally known and are used for measuring characteristics of fluids. Generally, vibratory meters comprise a sensor assembly and a meter electronics. The material in or about the sensor assembly may be flowing or stationary. The vibratory meter may be used to measure a mass flow rate, density, or other properties of a material in or about the sensor assembly. In particular, the sensor assembly may vibrate a vibratory structure that moves the material in or about the sensor assembly. In sensor assemblies comprising one or more conduits containing the material, the vibratory structure may be defined by a length of the one or more conduits. A length of the one or more conduits defined by the fixed ends may be referred to as a vibratory portion of the one or more conduits of the vibratory structure. Vibration nodes are defined where the one or more conduits are fixed at each end. The vibratory portion of the sensor assembly may therefore have at least one vibration mode defined in part by two vibration nodes. The ends of the vibratory portion of the vibratory structure may be referred to as end nodes of a vibration mode. All vibration modes of the vibratory portion will have at least the two end nodes. The sensor assembly may have two or more vibration modes. That is, the vibratory portion may have a first, second, third, etc. vibration mode. In many sensor assemblies, the normal modes are comprised of bend or twist modes. Bend modes are defined by symmetrical displacement of all points of the vibratory portion of the sensor assembly. Symmetrical displacement means that all locations of the conduit move in phase with each other. The twist mode may be defined by antisymmetric displacement of the vibratory portion of the sensor assembly. Antisymmetric displacement of a conduit means at least some locations of the conduit are not moving in phase with other locations of the conduit. For symmetrical structures of the vibratory portion, this may mean locations equidistant from a center location of the conduit are moving 180 degrees out-of-phase. Movement of the one or more conduits may be caused and / or sensed by a transducer. A transducer may be any device that converts between an electrical signal and a physical movement, which herein is a movement of the conduit. A transducer intended to cause the conduit to move can be referred to as a driver. A transducer intended to sense a movement may be referred to as a pickoff sensor. Other terms for a pickoff sensor may be employed, such as velocity or displacement sensor. The movement may be caused and / or sensed by a transducer coupled to the one or more conduits. The coupling may be direct and / or indirect, mechanical and / or electromechanical, etc. The vibratory motions may be driven or induced. The term “driven mode” or “driven vibration mode” means a vibration mode caused by a driver. That is, an electrical signal causes the transducer to apply a force to the conduit. The force may be referred to as a forcing function, where the forcing function has oscillation related parameters such as frequency or time-period, displacement and phase. An induced vibratory movement is caused by a force that is induced by the driven vibration mode. For example, a driven bend mode may cause a rotational angular velocity to be applied to a flowing material contained by a conduit, which induces a Coriolis force. The Coriolis force can cause an induced twisting of the conduit. The amount of twist, measured as a time delay or phase difference, is proportional to a mass flow rate of the material flowing through the conduit. The amount of twist can be used to measure a mass flow rate of the material with a suitable calibration. The conduit and / or the material contained by the conduit may have various parameters that are more desirably sensed and / or affected by particular vibration modes. However, no attempts have been made to exploit these benefits in a single vibratory meter. Additionally, various attempts that have been made used more than one vibratory sensor, employed complex electronics and / or sensor assemblies, or relied on induced vibration modes. There can also be benefits to being able to selectively operate a vibratory meter in two or more operating modes. There is a need therefore for operating a vibratory sensor in two or more vibration modes. There is also a need for operating a vibratory sensor in the two or more vibration modes without complex electronics and / or sensor assemblies. SUMMARY A method of operating a vibratory meter in two or more vibration modes is provided. According to an embodiment, the method comprises vibrating, with a drive signal, a sensor assembly in a first vibration mode, and vibrating, with the drive signal, the sensor assembly in a second vibration mode, wherein nodes of the first vibration mode and nodes of the second vibration mode are symmetrically located on a conduit of the sensor assembly. A vibratory meter configured to operate in two or more vibration modes is provided. According to an embodiment, the vibratory meter comprises a sensor assembly comprising a conduit and a driver disposed on the conduit, a meter electronics communicatively coupled to the sensor assembly, the meter electronics being configured to perform a method according to the foregoing. A method of operating a vibratory meter in two or more vibration modes is provided. According to an embodiment, the method comprises vibrating, with a drive signal, a sensor assembly in a first vibration mode and vibrating, with the drive signal, the sensor assembly in a second vibration mode, wherein the sensor assembly is asynchronously vibrated in the first vibration mode and the second vibration mode. A vibratory meter for operating in two or more vibration modes is provided. According to an embodiment, the vibratory meter comprises a sensor assembly, a meter electronics communicatively coupled with the sensor assembly, the meter electronics being configured to perform a method according to the foregoing. A system for vibrating a vibratory meter in two or more vibration modes is provided. According to an embodiment, the system comprises a first vibratory meter configured to operate in the two or more vibration modes, a second vibratory meter configured to operate in at least one of the two or more vibration modes, and a processor configured to perform a method according to one of the foregoing. A method of operating a vibratory meter in two or more vibration modes is provided. According to an embodiment, the method comprises switching a drive signal from a first transducer coupled to a conduit of a sensor assembly to a second transducer coupled to the conduit of the sensor assembly. A vibratory meter for operating in two or more vibration modes is provided. According to an embodiment, the vibratory meter comprises a sensor assembly and a meter electronics communicatively coupled with the sensor assembly, the meter electronics being configured to perform a method according to the foregoing. ASPECTS According to an aspect, a method of operating a vibratory meter in two or more vibration modes comprises vibrating, with a drive signal, a sensor assembly in a first vibration mode, and vibrating, with the drive signal, the sensor assembly in a second vibration mode, wherein nodes of the first vibration mode and nodes of the second vibration modes are symmetrically located on a conduit of the sensor assembly. Preferably, the sensor assembly further comprises a driver symmetrically disposed on a conduit of the sensor assembly. Preferably, the driver being symmetrically disposed on the conduit of the sensor assembly comprises the driver being disposed equidistance between brace bars coupled to the conduit. Preferably, the brace bars define end nodes of the first vibration mode and the second vibration mode. Preferably, the driver being symmetrically disposed on the conduit comprises the driver being disposed at a node of the nodes of the second vibration mode. Preferably, the driver being symmetrically disposed on the conduit of the sensor assembly comprises the driver being symmetrically disposed between two or more pickoff sensors disposed on the conduit of the sensor assembly. Preferably, the driver symmetrically disposed on the conduit of the sensor assembly is comprised of a single driver affixed to a center of the conduit. Preferably, the sensor assembly further comprises a pickoff sensor disposed on the conduit of the sensor assembly, wherein the drive signal is provided to one of the driver and the pickoff sensor. Preferably, vibrating the sensor assembly in the first vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the first vibration mode and vibrating the sensor assembly in the second vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the second vibration mode. Preferably, the first vibration mode is a first bend mode and the second vibration mode is one of a second bend mode and a first twist mode. Preferably, the drive signal applies a forcing function to the conduit at one of a symmetric location and an asymmetric location of the conduit. Preferably, the asymmetric location of the conduit is a location of an antinode of the first vibration mode and the symmetric location of the conduit is a location of a node of the second vibration mode. Preferably, vibrating, with the drive signal, the sensor assembly in the first vibration mode and the second vibration mode comprises providing the drive signal to a single transducer disposed on the conduit. According to an aspect, a vibratory meter configured to operate in two or more vibration modes comprises a sensor assembly comprising a conduit and a driver disposed on the conduit, a meter electronics communicatively coupled to the sensor assembly, the meter electronics being configured to perform a method according to the foregoing. According to an aspect, a method of operating a vibratory meter in two or more vibration modes comprises vibrating, with a drive signal, a sensor assembly in a first vibration mode and vibrating, with the drive signal, the sensor assembly in a second vibration mode, wherein the sensor assembly is asynchronously vibrated in the first vibration mode and the second vibration mode. Preferably, vibrating the sensor assembly in the first vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the first vibration mode and vibrating the sensor assembly in the second vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the second vibration mode. Preferably, the first vibration mode is a first bend mode, and the second vibration mode is one of a second bend mode and a first twist mode. Preferably, a driver is symmetrically disposed on a conduit of the sensor assembly. Preferably, the driver being symmetrically disposed on the conduit of the sensor assembly comprises the driver being symmetrically disposed between two or more pickoff sensors disposed on the conduit of the sensor assembly. Preferably, the drive signal applies a forcing function to a conduit of the sensor assembly at one of a symmetric location and an asymmetric location of the conduit. Preferably, the asymmetric location of the conduit is a location of an antinode of the first vibration mode and the symmetric location of the conduit is a location of a node of the second vibration mode. Preferably, vibrating, with the drive signal, the sensor assembly in the first vibration mode and the second vibration mode comprises providing the drive signal to a single transducer disposed on a conduit of the sensor assembly. Preferably, the method further comprising coordinating between the vibratory meter and a second vibratory meter to asynchronously vibrate the sensor assembly in the first vibration mode and second vibration mode. Preferably, coordinating between the vibratory meter and the second vibratory meter comprises determining if a frequency related calibration constant value of the vibratory meter is substantially the same as a frequency related calibration constant value of the second vibratory meter. Preferably, the frequency related calibration constant relates a fundamental frequency of a vibration mode with a density value of a material contained by a conduit of the sensor assembly. Preferably, coordinating between the vibratory meter and the second vibratory meter comprises causing the vibratory meter to vibrate in the first vibration mode if the second vibratory meter is vibrating in the second vibration mode. According to an aspect, a vibratory meter for operating in two or more vibration modes comprises a sensor assembly, a meter electronics communicatively coupled with the sensor assembly, the meter electronics being configured to perform a method according to the foregoing. According to an aspect, a system for vibrating a vibratory meter in two or more vibration modes comprises a first vibratory meter configured to operate in the two or more vibration modes, a second vibratory meter configured to operate in at least one of the two or more vibration modes, and a processor configured to perform a method according to one of the foregoing. Preferably, the second vibratory meter being configured to operate in at least one of the two or more vibration modes comprises the second vibratory meter being configured to operate in the two or more vibration modes. Preferably, the processor is part of at least one of a meter electronics of the first vibratory meter and a meter electronics of the second vibratory meter. Preferably, the processor is configured to cause the second vibratory meter to vibrate at a vibration mode that is different than a vibration mode of the first vibratory meter. According to an aspect, a method of operating a vibratory meter in two or more vibration modes comprises switching a drive signal from a first transducer coupled to a conduit of a sensor assembly to a second transducer coupled to the conduit of the sensor assembly. Preferably, the first transducer is located at a node of a second vibration mode and the second transducer located away from the node of the second vibration mode. Preferably, the first transducer is a driver and the second transducer is a pickoff sensor. Preferably, the pickoff sensor is one of a left pickoff sensor and a right pickoff sensor coupled to the conduit of the sensor assembly. Preferably, the method further comprises a third transducer, wherein the first transducer is symmetrically disposed between the second transducer and the third transducer. Preferably, the first transducer being symmetrically disposed between the second transducer and the third transducer comprises the first transducer being symmetrically equidistant between the second transducer and the third transducer. Preferably, the method further comprises vibrating, with a drive circuit, a sensor assembly of the vibratory meter in a first vibration mode, and vibrating, with the drive circuit, the sensor assembly of the vibratory meter in a second vibration mode. Preferably, the first vibration mode is a first bend mode and the second vibration mode is a twist mode. Preferably, switching the drive signal comprises switching the drive signal with one or more relay switches disposed between a signal generator and the sensor assembly. Preferably, the method further comprises receiving with the one or more relay switches a signal commanding the one or more relay switches to switch the drive signal. Preferably, the method further comprises switching the drive signal from the second transducer coupled to the conduit of the sensor assembly to the first transducer coupled to the conduit of the sensor assembly. Preferably, switching the drive signal from the first transducer to the second transducer and switching the drive signal from the second transducer to the first transducer comprises asynchronously switching the drive signal from the first transducer to the second transducer and switching the drive signal from the second transducer to the first transducer. Preferably, the method further comprises switching a sensor signal from the second transducer coupled to the conduit of a sensor assembly to the first transducer coupled to the conduit of the sensor assembly. Preferably, switching the drive signal and switching the sensor signal comprises contemporaneously switching the drive signal and switching the sensor signal. According to an aspect, a vibratory meter for operating in two or more vibration modes comprises a sensor assembly and a meter electronics communicatively coupled with the sensor assembly, the meter electronics being configured to perform a method according to the foregoing. BRIEF DESCRIPTION OF THE DRAWINGS The same reference number represents the same element on all drawings. It should be understood that the drawings are not necessarily to scale. FIG.1 shows a vibratory meter 5 for operating in two or more vibration modes. FIG.2 shows a block diagram of the vibratory meter 5, including a block diagram representation of the meter electronics 20. FIG.3 shows the meter electronics 20 for operating a vibratory meter in two or more vibration modes. FIGS.4A and 4B show wireline diagrams of conduits to illustrate vibration modes of the conduits, such as the conduits 130, 130’ described above. FIGS.5A-5C and FIGS. 6A-6C respectively show perspective and lateral views of a sensor assembly 510 of a vibratory meter having the vibratory modes described above with reference to FIGS. 4A and 4B. FIG.7 shows a three degree of freedom graph 700 for operating a vibratory meter in two or more vibration modes. FIG. 8 shows a graph 800 illustrating adding two signals having different frequencies. FIG. 9 shows a vibratory meter 905 configured to have an induced twist mode for operating the vibratory meter 905 in two or more vibration modes. FIG. 10 shows a switching circuit 1000 for inducing a twist mode in a sensor assembly. FIG. 11 shows a multi-sensor assembly system 1100 for operating a vibratory meter in two or more vibration modes. FIG. 12 shows an aggregate frequency response function (“FRF”) graph 1200 illustrating FRFs corresponding to the nominal and twist configurations of the meter electronics 920. FIG. 13 shows a graph 1300 illustrating sensor signals plotted in a time domain when an asymmetrical forcing function is applied to a conduit. FIG. 14 shows a drive signal frequency spectrum graph 1300. FIG. 15 shows frequency response function 1400 for verifying a vibratory meter operating in two or more vibration modes. FIG. 16 shows a block diagram of a vibratory meter 1605 including meter verification using two or more fundamental frequencies. FIG. 17 shows a method of operating a vibratory meter in two or more vibration modes. FIG. 18 shows a method 1800 of operating a vibratory meter in two or more vibration modes. DETAILED DESCRIPTION FIGS.1 – 18 and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of embodiments of operating a vibratory meter in two or more vibration modes. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these examples that fall within the scope of the present description. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of operating the vibratory meter in two or more vibration modes. As a result, the embodiments described below are not limited to the specific examples described below, but only by the claims and their equivalents. FIG. 1 shows a vibratory meter 5 for operating in two or more vibration modes. As shown in FIG.1, the vibratory meter 5 comprises a sensor assembly 10 and meter electronics 20. The sensor assembly 10 responds to mass flow rate and density of a process material. The meter electronics 20 is connected to the sensor assembly 10 via leads 100 to provide density, mass flow rate, and temperature information over port 26, as well as other information. The sensor assembly 10 includes a pair of manifolds 150 and 150', flanges 103 and 103' having flange necks 110 and 110', a pair of parallel conduits 130 and 130', driver 180, resistive temperature detector (RTD) 190, and a pair of pick-off sensors 170l and 170r. Conduits 130 and 130' have two essentially straight inlet legs 131, 131' and outlet legs 134, 134', which converge towards each other at conduit mounting blocks 120 and 120'. The conduits 130, 130' bend at two symmetrical locations along their length and are essentially parallel throughout their length. Brace bars 140 and 140' serve to define the axis W and W' about which each conduit 130, 130’ oscillates. The legs 131, 131' and 134, 134' of the conduits 130, 130' are fixedly attached to conduit mounting blocks 120 and 120' and these blocks, in turn, are fixedly attached to manifolds 150 and 150'. This provides a continuous closed material path through sensor assembly 10. When flanges 103 and 103', having holes 102 and 102' are connected, via inlet end 104 and outlet end 104' into a process line (not shown) which carries the process material that is being measured, material enters inlet end 104 of the meter through an orifice 101 in the flange 103 and is conducted through the manifold 150 to the conduit mounting block 120 having a surface 121. Within the manifold 150 the material is divided and routed through the conduits 130, 130'. Upon exiting the conduits 130, 130', the process material is recombined in a single stream within the block 120’ having a surface 121’ and the manifold 150' and is thereafter routed to outlet end 104' connected by the flange 103' having holes 102' to the process line (not shown). The conduits 130, 130' are selected and appropriately mounted to the conduit mounting blocks 120, 120' so as to have substantially the same mass distribution, moments of inertia and Young's modulus about bending axes W--W and W'--W', respectively. These bending axes go through the brace bars 140, 140'. Inasmuch as the Young's modulus of the conduits change with temperature, and this change affects the calculation of flow and density, RTD 190 is mounted to conduit 130' to continuously measure the temperature of the conduit 130’. The temperature of the conduit 130’ and hence the voltage appearing across the RTD 190 for a given current passing therethrough is governed by the temperature of the material passing through the conduit 130’. The temperature dependent voltage appearing across the RTD 190 is used in a well-known method by the meter electronics 20 to compensate for the change in elastic modulus of the conduits 130, 130' due to any changes in conduit temperature. The RTD 190 is connected to the meter electronics 20 by lead 195. Both of the conduits 130, 130' are driven by driver 180 in opposite directions about their respective bending axes W and W' and at what is termed the first out-of- phase bending mode of the flow meter. This driver 180 may comprise any one of many well-known arrangements, such as a magnet mounted to the conduit 130' and an opposing coil mounted to the conduit 130 and through which an alternating current is passed for vibrating both conduits 130, 130’. A suitable drive signal 185 is applied by the meter electronics 20, via a lead, to the driver 180. The meter electronics 20 receives the RTD temperature signal on lead 195, and sensor signals 165 appearing on leads 100 carrying left and right sensor signals 165l, 165r, respectively. The meter electronics 20 produces the drive signal 185 appearing on the lead to driver 180 and vibrate conduits 130, 130'. The meter electronics 20 processes the left and right sensor signals 165l, 165r and the RTD signal 195 to compute the mass flow rate and the density of the material passing through sensor assembly 10. This information, along with other information, is applied by meter electronics 20 over path 26 as a signal. A more detailed discussion of the meter electronics 20 follows. FIG.2 shows a block diagram of the vibratory meter 5, including a block diagram representation of the meter electronics 20. As shown in FIG. 2, the meter electronics 20 is communicatively coupled to the sensor assembly 10. As described in the foregoing with reference to FIG.1, the sensor assembly 10 includes the left and right pick-off sensors 170l, 170r, driver 180, and temperature sensor 190, which are communicatively coupled to the meter electronics 20 via the set of leads 100 through a communications channel 112. The meter electronics 20 provides a drive signal 185 via the leads 100. More specifically, the meter electronics 20 provides a drive signal 185 to the driver 180 in the sensor assembly 10. In addition, sensor signals 165 comprising the left sensor signal 165l and the right sensor signal 165r are provided by the sensor assembly 10. More specifically, in the embodiment shown, the sensor signals 165 are provided by the left and right pick-off sensor 170l, 170r in the sensor assembly 10. As can be appreciated, the sensor signals 165 are respectively provided to the meter electronics 20 through the communications channel 112. The meter electronics 20 includes a processor 210 communicatively coupled to one or more signal processors 220 and one or more memories 230. The processor 210 is also communicatively coupled to a user interface 30. The processor 210 is communicatively coupled with the host via a communication port over the port 26 and receives electrical power via an electrical power port 250. The processor 210 may be a microprocessor although any suitable processor may be employed. For example, the processor 210 may be comprised of sub-processors, such as a multi-core processor, serial communication ports, peripheral interfaces (e.g., serial peripheral interface), on- chip memory, I / O ports, and / or the like. In these and other embodiments, the processor 210 is configured to perform operations on received and processed signals, such as digitized signals. The processor 210 may receive digitized sensor signals from the one or more signal processors 220. The processor 210 is also configured to provide information, such as a phase difference, a property of a fluid in the sensor assembly 10, or the like. The processor 210 may provide the information to the host through the communication port. The processor 210 may also be configured to communicate with the one or more memories 230 to receive and / or store information in the one or more memories 230. For example, the processor 210 may receive calibration factors and / or sensor assembly zeros (e.g., phase difference when there is zero flow) from the one or more memories 230. Each of the calibration factors and / or sensor assembly zeros may respectively be associated with the flow meter 5 and / or the sensor assembly 10. The processor 210 may use the calibration factors to process digitized sensor signals received from the one or more signal processors 220. The one or more signal processors 220 is shown as being comprised of an encoder / decoder (CODEC) 222 and an analog-to-digital converter (ADC) 226. The one or more signal processors 220 may condition analog signals, digitize the conditioned analog signals, and / or provide the digitized signals. The CODEC 222 is configured to receive the sensor signals 165 from the left and right pick-off sensors 170l, 170r. The CODEC 222 is also configured to provide the drive signal 185 to the driver 180. In alternative embodiments, more or fewer signal processors may be employed. As shown, the sensor signals 165 are provided to the CODEC 222 via a signal conditioner 240. The drive signal 185 is provided to the driver 180 via the signal conditioner 240. Although the signal conditioner 240 is shown as a single block, the signal conditioner 240 may be comprised of signal conditioning components, such as two or more op-amps, filters, such as low pass filters, voltage-to-current amplifiers, or the like. For example, the sensor signals 165 may be amplified by a first amplifier and the drive signal 185 may be amplified by the voltage-to-current amplifier. The amplification can ensure that the magnitude of the sensor signals 165 is approximate the full-scale range of the CODEC 222. The portion of the CODEC 222 and signal conditioner 240 that generates the drive signal 185 may be referred to as a signal generator. The portion of the CODEC 222 and signal conditioner 240 that receives and processes the sensor signals 165 may be referred to as a sensor signal processor. It should be appreciated that the portions of the signal generator and the sensor signal processor that work together to generate the drive signal at a resonance frequency of the sensor assembly 10 may be referred to as a drive circuit. It should also be appreciated that the drive circuit can include additional components, such as switches, additional signal processors, and / or the like. In the embodiment shown, the one or more memories 230 is comprised of a read- only memory (ROM) 232, random access memory (RAM) 234, and a ferroelectric random-access memory (FRAM) 236. However, in alternative embodiments, the one or more memories 230 may be comprised of more or fewer memories. Additionally, or alternatively, the one or more memories 230 may be comprised of different types of memory (e.g., volatile, non-volatile, etc.). For example, a different type of non-volatile memory, such as, for example, erasable programmable read only memory (EPROM), or the like, may be employed instead of the FRAM 236. The one or more memories 230 may be a storage configured to store process data, such as drive or sensor signals, mass flow rate or density measurements, etc. Amass flow rate measurement (^^ ) can be generated according to the equation:^^ = ^^^[∆^ − ∆^^] [1]The ∆t term comprises an operationally-derived (i.e., measured) time delay value comprising the time delay existing between the pickoff sensor signals, such as where the time delay is due to Coriolis effects related to mass flow rate through the vibratory flowmeter 5. The measured ∆t term ultimately determines the mass flow rate of the flow material as it flows through the vibratory flowmeter 5. The ∆t0 term comprises a time delay / phase difference at zero flow calibration constant. The ∆t0term is typically determined at the factory and programmed into the vibratory flowmeter 5. The time delay / phase difference at zero flow ∆t0 term will not change, even where flow conditions are changing. A mass flow rate of flow material flowing through the flow meter is determined by multiplying a measured time delay (or phase difference / frequency) by the flow calibration factor FCF. The flow calibration factor FCF is proportional to a physical stiffness of the flow meter. As to density, a resonance frequency at which each conduit 130, 130’ will vibrate may be a function of the square root of a spring constant of the conduit 130, 130’ divided by the total mass of the conduit 130, 130’ having a material. The total mass of the conduit 130, 130’ having the material may be a mass of the conduit 130, 130’ plus a mass of a material inside the conduit 130, 130’. The mass of the material in the conduit 130, 130’ is directly proportional to the density of the material. Therefore, the density of this material may be proportional to the square of a period at which the conduit 130, 130’ containing the material oscillates multiplied by the spring constant of the conduit 130, 130’. Hence, by determining the period at which the conduit 130, 130’ oscillates and by appropriately scaling the result, an accurate measure of the density of the material contained by the conduit 130, 130’ can be obtained. The meter electronics 20 can determine the period or resonance frequency using the sensor signals 165 and / or the drive signal 185. The density value can be obtained by using calibration constants. Calibration to determine the FCF for determining the mass flow rate and density calibration constants can use fluids of known density. For example, two fluids with different densities may be used, such as water and air. Density can be calculated using a density equation that include the density calibration constants, such as Equation [2]: ^= ^0 + ^1^ + ^2^^; Equation [2]where: ^ is a density, which may not be corrected for other process related parameters like temperature; ^ is a tube time-period or periodic time of a conduit in, for example, micro- seconds (^^); and ^0, ^1, ^2 are calibration constants.As explained above, the conduits 130, 130’ can vibrate in two or more modes. Parameters of two or more vibration modes, which may be referred to as mode parameters or vibration mode parameters, can be analyzed to detect, determine, analyze, and / or the like process related parameters. The process related parameters may include fluid parameters, sensor assembly parameters, meter electronics parameters, environmental parameters, etc. That is, process related parameters may be any parameter that influences and / or indicates something that is related to a process of which the vibratory meter is a component. By way of illustration, process related parameters may include a pressure or temperature of a fluid contained by the conduits 130, 130’, air or other fluid surrounding the conduits 130, 130’s, temperature of the manifolds 150, 150’, orientation of the sensor assembly 10, a case surrounding the conduits 130, 130’, etc. Such detection, determination, analysis, and / or the like can be performed by the meter electronics 20. Meter electronics FIG. 3 shows the meter electronics 20 for operating a vibratory meter in two or more vibration modes. As shown in FIG.3, the meter electronics 20 includes an interface 301 and a processing system 302. The meter electronics 20 receives a vibrational response, such as from the sensor assembly 10, for example. The meter electronics 20 processes the vibrational response in order to obtain flow characteristics of the flow material flowing through the sensor assembly 10. The interface 301 may receive the sensor signals 165 from one of the pick-off sensors 170l, 170r shown in FIGS.1 and 2. The interface 301 can perform any necessary or desired signal conditioning, such as any manner of formatting, amplification, buffering, etc. Alternatively, some or all of the signal conditioning can be performed in the processing system 302. In addition, the interface 301 can enable communications between the meter electronics 20 and external devices. The interface 301 can be capable of any manner of electronic, optical, or wireless communication. The interface 301 can provide information based on the vibrational response. The interface 301 may be coupled with a digitizer, such as the CODEC 222 shown in FIG.2, wherein the sensor signal comprises an analog sensor signal. The digitizer samples and digitizes an analog sensor signal and produces a digitized sensor signal. The processing system 302 conducts operations of the meter electronics 20 and processes flow measurements from the sensor assembly 10. The processing system 302 executes one or more processing routines and thereby processes the flow measurements in order to produce one or more flow characteristics. The processing system 302 is communicatively coupled to the interface 301 and is configured to receive the information from the interface 301. The processing system 302 can comprise a general-purpose computer, a micro- processing system, a logic circuit, or some other general purpose or customized processing device. Additionally, or alternatively, the processing system 302 can be distributed among multiple processing devices. The processing system 302 can also include any manner of integral or independent electronic storage medium, such as the storage system 304. The storage system 304 can store flow meter parameters and data, software routines, constant values, and variable values. In one embodiment, the storage system 304 includes routines that are executed by the processing system 302, which will be discussed in more detail in the following. As shown in FIG.3, the storage system 304 includes an operational routine 310, a calibration routine 320, calibration information 330, correction routines 340, meter verification routines 350, multiplexing routines 360, and multi-phase routines 370, although more, fewer, and / or alternative routines may be stored and / or employed. The storage system can also store statistical values, such as a standard deviation, confidence intervals, or the like. The operational routine 310 can determine a mass flow rate and / or a density value according to the above equations [1] and [2], although any suitable equation, relationships, etc., can be employed. The operational routine 310 can also determine various other fluid parameters, such as viscosity, fluid velocity, velocity of sound, fluid phase ratios, such as gas-mass ratios, void fractions, etc., and / or the like. The operational routine 310 can determine the fluid parameter values based on one or more vibration modes. For example, a mass flow rate may be determined based on a first bend mode, such as an out of phase bend mode. Additionally, or alternatively, and as will be described in more detail below, the operational routine 310 can determine other process related parameter values based on two or more vibration modes. The calibration routine 320 can determine various calibration factors, which may be calibration coefficients, constants, etc. The calibration routine 320 can determine, forexample, flow calibration factor FCF value(s), density calibration constants ^0, ^1, ^2used to determine a density value, a temperature value based on the RTD signal 190, and / or the like. Other calibration factors additional or alternative to those discussed herein can be employed. The calibration constants can relate a sensed physical phenomenon to a measured value of the sensed phenomenon or other phenomenon. Calibration factors, as well as any other calibration related information can be stored in the calibration information 330. The correction routine 340 may compensate a measurement, such as a mass flow rate measurement, for an orientation of a vibratory meter. For example, the correction routine 340 may use various process related parameter values to compensate another process related parameter value. By way of illustration, a temperature of the process fluid can be used to correct a measured mass flow rate of a material flowing through a vibratory meter, such as the vibratory meter 5 described above. The meter verification routines 350 can verify that a sensor assembly, such as the sensor assembly 10 described above, does not have erosion, corrosion, deposits, and / or the like that can affect a measurement of fluid parameter. The multiplexing routines 360 can provide a drive signal to one or more transducers that are coupled to a conduit, such as the transducers described in the foregoing. For example, the multiplexing routine 360 can provide a drive signal that is at a first frequency corresponding to a first fundamental frequency and a second frequency corresponding to a second fundamental frequency. The first and second frequency may be provided in time division multiplex or frequency division multiplexed form. That is, the first and second frequency can be provided sequentially or simultaneously. The multi-phase routines 370 can determine if a fluid is in multi-phase condition, perform corrections of measured values using adjustments and / or the like based on the two or more vibration modes. For example, a totalization may be avoided by detecting a false flow condition in a sensor assembly. Additionally, or alternatively, the multi-phase routine 370 can adjust a mass flow rate of a flow based on a ratio of phases in a multi- phase fluid flow. As will be explained in more detail in the following, one or more of the above- described routines can operate a vibratory meter in two or more vibration modes of a sensor assembly. For example, a process related parameter may be determined, a meter verification may be performed, a mass flow rate may be compensated for multiphase effects, etc. Vibration modes FIGS. 4A and 4B show wireline diagrams of conduits to illustrate vibration modes of the conduits, such as the conduits 130, 130’ described above. As shown in FIGS.4A and 4B, the conduits are depicted by wirelines 410. The wirelines 410 have a U-shape to reflect U-shaped conduits, which may be comprised of a left conduit and a right conduit. As shown in FIGS.4A and 4B, the wirelines 410 include a left at-rest wireline 412a and a right at-rest wireline 412b. Also shown in FIGS. 4A and 4B are bend axes W—W, W’—W’, which is collocated with a vibration node of the wirelines 410. In FIG.4A, the wirelines 410 also include a left first order bend mode wireline 414a and a right first order bend mode wireline 414b. Also shown are a left second order bend mode wireline 416a and a right second order bend mode wireline 416b. In FIG. 4B, the wirelines 410 include a left first order twist mode 418a and a right first order twist mode 418b. The left and right first order bend mode wirelines 414a, 414b are shown by arrows to be 180 degrees out of phase. That is, they move in an opposing manner. This may be beneficial in various ways, such as reducing a vibration of a vibratory meter due to an unbalanced displacement of the conduits. The left and right first order bend mode wirelines 414a, 414b are also shown as having a single node, which is collocated with the bend axes W—W, W’—W’. The left and right second order bend mode wirelines 416a, 416b are also shown by arrows to be 180 degrees out of phase with each other. However, the left and right second order bend mode wirelines 416a, 416b have two vibration nodes, hence the term “second order.” A natural frequency of the left and right second order bend mode wirelines 416a, 416b may be higher than a natural frequency of the left and right first order bend mode wirelines 414a, 414b. The left first order twist mode 418a and the right first order twist mode 418b are shown as having asymmetric displacement relative to the left and right at-rest wirelines 412a, 412b along their respective lengths. Arrows illustrate that the left and right first order twist modes 418a, 418b are out of phase with each other. The vibration modes illustrated by the wirelines 410 are shown as being separate but may be superimposed onto the conduits modeled by the wirelines 410. That is, the conduits modeled by the wirelines 410 may have multiple vibration modes. For example, a left conduit of the conduits may have a first order bend mode, a second order bend mode, and a twist mode. Accordingly, the conduits may have a first order out of phase bend mode, a second order out of phase bend mode, and a first order twist mode. The conduits may have additional modes, such as higher order bend modes (e.g., third, fourth, fifth, etc.), in-phase bend modes, and higher order twist modes (e.g., second, third, fourth, etc.). As the foregoing illustrates, a vibration mode may have a shape, amplitude, and natural frequency. The shape of the vibration modes can be detected by comparing the sensor signals, such as the sensor signals 165, to each other. A phase difference between a sensor signal provided by the left pick-off sensor 170l and a sensor signal provided by the right pick-off sensor signal 170r may indicate a twist mode excitation caused by Coriolis forces due to flow through the vibratory meter as the tubes vibrate in a bending or other mode, and may be proportional to the phase difference between the conduits 130, 130’. The amplitude of the vibration modes may be proportional to an amplitude of the sensor signals 165. The frequencies of the vibration modes may be determined from the sensor signals 165 and / or the drive signal 185. More specifically, due to each vibration mode having a natural mode frequency, the sensor signals 165 may have components that correspond to the vibration modes of the conduits 130, 130’. Accordingly, filtering may be used to isolate the components to determine a frequency of each component. The frequency of each component corresponds to the frequency of a vibration mode. The frequencies of the vibration modes may be referred to individually as a mode frequency. That is, the mode frequency is a natural frequency of a vibration mode, each of which corresponds to a component in the sensor signals 165 and / or the drive signal 185. The vibration modes may have relationships. For example, a relationship between two vibration modes, herein referred to as a mode relationship, may be based on the phase, amplitude, and frequency of the two vibration modes. In one example, a mode relationship may be a difference in a frequency of the left and right second order bend mode wirelines 416a, 416b and a frequency of the left and right first order bend mode wirelines 414a, 414b. The mode relationship may be quantified as mode difference. For example, the mode relationship may be a difference between a time- period of the left and right second order bend mode wirelines 416a, 416b relative to a time-period of the left and right first order bend mode wirelines 414a, 414b. A mode relationship may also be something other than a difference, such as relative values like ratios, percentages, etc. By way of illustration, a mode relationship may be a frequency ratio, difference, etc. Accordingly, a mode relationship can be indicated by a term that reflects the vibration mode and the vibration mode parameter. For example, a time-period of a vibration may be indicated as ^^^where “MO” is a variable to denote the mode (m) and the order (O). The modes can be denoted by β and ζ respectively as bend and twist mode. The order may be denoted by 1, 2, 3. So a first order bend mode and a first order twist mode can be respectively denoted as β1 and ζ1. A first order bend mode and a second order bend mode may be denoted as β1 and β2. Accordingly, a difference of time periods between the first and second order bend modes may be defined as ^^^ − ^^^.This can be shortened to ^^^^^^. Similarly, frequencies of the first and second order bend modes may by be denoted by ^ , ^ where a differe ^^ ^^ nce between frequenciesis indicated by ^^^ − ^^^, which can be shortened to ^^^^^^. Similarly, a frequencyratio between and second bend mode may be denoted by ^^^⁄ ^^^ , which, in this example, is than 1 because the second bend mode has a fundamental frequency greater than a fundamental frequency of the first bend mode. As will be explained in more detail in the following, a calibration may be performed such that conduit stress inducing parameters, such as material pressure, temperature gradient, etc., can be determined from the vibration mode parameters. Accordingly, the nomenclature where the first order bend mode and a first order twist mode are respectively denoted as β1 and ζ1 can be used for conduit stress inducing parameters, such as, for example, pressure or temperature. For example, a pressure determined using the first order bend mode and the second order bend mode may be defined by^^^^. A conduit stress inducing parameter gradient may be denoted by the symbol ∇. Accordingly, a pressure gradient determined based on the first and second bend modes can be denoted by ∇^^^^. Similarly, a pressure determined based on, for example, a frequency ratio of the first and second bend mode may be denoted by (^^^⁄ ^^^ ), where the second bend mode frequency is a numerator of the frequency Generally, stress in a conduit is due to a gradient of a stress inducing parameter. For example, a pressure gradient between the material pressure and the ambient pressure induces a stress in the conduit. Similarly, a temperature gradient along a conduit induces a stress in the conduit. However, it may be a reasonable assumption that, for example, a stress in a conduit is correlated with a material pressure due to the ambient pressure being a relatively small and / or consistent value. Accordingly, it should be appreciated that an absolute or relative conduit stress inducing parameter may be employed. For example, a material pressure may be used rather than a pressure gradient between the material pressure and ambient pressure, although the pressure gradient induces the stress. Stresses in conduits FIGS. 5A-5C and FIGS.6A-6C respectively show perspective and lateral views of a sensor assembly 510 of a vibratory meter having the vibratory modes described above with reference to FIGS. 4A and 4B. As shown in FIGS.5A-5C and FIGS. 6A-6C, the sensor assembly 510 has a U-shaped configuration in consistent with the U-shape of the wirelines 410 of FIGS.4A and 4B. As shown in FIGS.5A-5C and FIGS.6A-6C, the sensor assembly 510 comprised of conduits 513, 513’ that are mechanically fixed to mounting blocks 512, 512’. As with the vibratory meter 5 of FIG.1, brace bars 514 and 514' serve to define the axis W and W' about which each conduit 513, 513’ oscillates. As shown in FIGS. 5A and 6A, the sensor assembly 510 is in a first out of phase bend mode. As shown in FIGS. 5B and 6B, the sensor assembly 510 is in a first twist mode. As shown in FIGS. 5C and 6C, the sensor assembly 510 is in a second out of phase bend mode. It should be appreciated that the amount of displacement in the vibration modes are exaggerated such that the conduits 513513’ appear merged together or overlapping where the conduits 513, 513’ are displaced towards each other. As can be appreciated from FIGS. 5A-6C, a stress in the conduits 513, 513’ can affect parameters of the vibration modes. For example, a pressure gradient that increases a stiffness of the conduits 513, 513’ can increase a fundamental frequency of each vibration mode. However, the effect of the stress on a fundamental frequency of a given vibration mode may be more than the effect of the stress on a fundamental frequency of a different vibration mode. Accordingly, for example, a frequency ratio of fundamental frequencies of two different vibration modes may correspond to the stress. Similar effects can be observed with tube time periods of each vibration mode, etc. As is explained in more detail in the following, various vibration modes can be driven, and each vibration mode’s parameters can be detected and measured. Vibration model of a conduit FIG. 7 shows a three degree of freedom graph 700 for operating a vibratory meter in two or more vibration modes. As shown in FIG. 7, the three degree of freedom graph 700 is comprised of a mode shape graph 702 and a three degree of freedom model 704. The mode shape graph 702 is comprised of a conduit location axis 712 and a displacement axis 722, both of which may be in units of length. The conduit location axis 712 indicates a position along a conduit where the ends of the conduit location axis 712 are defined by brace bars, such as the brace bars 514, 514’ shown in FIGS.5A-6C. The mode shape graph 702 includes mode plots 732 comprised of a first bend mode plot 732a, a twist mode plot 732b, and a second bend mode plot 732c. The three degree of freedom model 704 is shown as being comprised of sensor masses, shown as comprising a left pickoff mass LPO, a driver mass DR, and a right pickoff mass RPO, springs 744, and dampers 724. It should be appreciated that the markers of the three modes correspond to the masses of the left and right pickoff sensors LPO, RPO and the driver DR. As discussed above, node locations of a given vibration mode are locations of zero displacement (indicated by a dashed line located at “0” on the displacement axis 722) of a conduit vibrating in the vibration mode, which may be an excited vibration mode. It should be appreciated that the nodes of the vibration modes are symmetrically located on a conduit. That is, first bend mode plot 732a, twist mode plot 732b, and second bend mode plot 732c include end nodes that are equidistant from a center location of a conduit. The location of the end nodes may be determined by a brace bar or other suitable structure that can function as an anchor 764. The twist mode plot 732b shows a center node that is coincident with the driver mass DR. As can be appreciated, the center node is equidistant between the end nodes defined by the anchors 764 and is therefore symmetrically located. The second bend mode plot 732c illustrates an approximate location of nodes where the second bend mode plot 732c is at zero displacement, which are also symmetrically located on the conduit. Non-nodal locations of a given vibration mode can be determined where the first bend mode plot 732a, twist mode plot 732b, and second bend mode plot 732c are non-zero. The locations relative to the conduit location axis 712 of maximal displacement of the first bend mode plot 732a, twist mode plot 732b, and second bend mode plot 732c may be referred to as antinodes. The three degree of freedom model 704 is a simplified model of a conduit of a sensor assembly developed to illustrate the use of two or more vibration modes. The three degree of freedom model 704 representation lumps the mass, stiffness and damping of a conduit into a system that may be simple to analyze. The three lumped masses LPO, RPO, DR represent the pickoffs and driver of a conduit. Values for mass, stiffness and damping were chosen so that the modal frequencies are like those of an actual sensor assembly. Accordingly, FIG.7 depicts the three degree of freedom model 704 and its mode shapes in the mode shape graph 702. Mode 1 represents the first bending mode, the traditional mode which is driven. Mode 2 represents the first twist mode. Mode 3 is a higher mode which can be driven by the same driver that drives Mode 1. Mode 3 and Mode 1 can also be driven simultaneously as the following discussion illustrates. FIG. 8 shows a graph 800 illustrating adding two signals having different frequencies. As shown in FIG.8, the graph 800 includes a time-axis 810 and a magnitude axis 820, which may be in any suitable units. The graph 800 also includes three signals 830. The three signals 830 are comprised of a first signal 830a, a second signal 830b, and a third signal 830c. The first and second signals 830a, 830b are shown as being sinusoidal signals respectively having a first and second frequency f1, f2. The first signal 830a may be a first mode signal or, with more particularity, a mode signal associated with a first vibration mode. The second signal 830b may similarly be a second mode signal associated with a second vibration mode. For example, the first mode may be a first bend mode and the second mode may be a second bend mode. The third signal 830c is shown as being comprised of a summation of the first and second signal 830a, 830b. For example, a mixer may be employed to receive an input and mix the first and second signal 830a, 830b to obtain the third signal 830c. Accordingly, the third signal is not a simple sinusoidal signal but instead is a signal having two sinusoidal components at the first and second frequency f1, f2. It should be appreciated that the three signals 830 may drive signals that are provided to a sensor assembly. For example, a drive circuit in the meter electronics 20 described above may be configured to generate the first and second signals 830a, 830b and mix the first and second signals 830a, 830b to obtain the third signal 830c. The third signal 830c may be provided to a sensor assembly, such as the sensor assembly 10 described above with reference to FIGS.1 and 2. It should be appreciated that the first signal 830a and the second signal 830b may be generated based on a feedback from the sensor assembly. That is, a feedback loop may receive and process signals corresponding to two or more vibration modes. Accordingly, the first and second signal 830a, 830b may be provided to the sensor assembly simultaneously to drive the first and second out of phase bend modes shown in, for example, FIGS. 5A, 6A and 5C, 6C. However, it should be appreciated that non-simultaneous signals may be provided. Additionally, or alternatively, a drive signal that drives a twist mode may be provided, as the following discussion explains. Twist mode circuit FIG. 9 shows a vibratory meter 905 configured to have a driven twist mode for operating the vibratory meter 905 in two or more vibration modes. As shown in FIG.9, the vibratory meter 905 is comprised of the sensor assembly 10 described with reference to FIGS. 1 and 2. That is, the sensor assembly 10 includes the driver 180 that is located equidistant between the left and right pickoff sensors 170r, 170l. The sensor assembly 10 is communicatively coupled with the meter electronics 920. As will be explained in more detail in the following, the meter electronics 920 is configured to provide a drive signal that drives a twist mode in the sensor assembly 10, rather than the first and / or second out of phase bend mode that may be provided by the meter electronics 20 described with reference to FIGS. 1 and 2. The meter electronics 920 shown in FIG.9 includes all the components described with reference to FIG. 2. However, the meter electronics 920 shown in FIG. 9 also includes a signal switch 902 that connects the drive signal output of the signal conditioner 240 with the left pickoff sensor 170l and the driver 180 with the left pickoff sensor input of the signal conditioner 240. This connection may be referred to as a “twist mode” configuration and is shown in FIG.9. As can be appreciated, in the “twist mode” configuration, the meter electronics 920 provides a drive signal to the left pickoff sensor 170l and the driver 180 provides a pickoff sensor signal to the meter electronics 920. The pickoff sensor signal provided by the driver 180 to the meter electronics 920 is proportional to a displacement parameter of the conduit at the location of the driver 180. It should be appreciated that the drive signal provided to the left pickoff sensor 170l may be a sinusoidal signal having a frequency that is a fundamental frequency of the twist mode. As can be appreciated, the signal switch 902 is part of the meter electronics 920. However, other switches do not need to be part of the meter electronics 920, as the following explains. FIG.10 shows a switching circuit 1000 for driving a twist mode in a sensor assembly. As shown in FIG.10, the switching circuit 1000 is comprised of first connector 1001 coupled with a second connector 1003. The first and second connector 1001, 1003 are shown as being disposed electrically and mechanically between a sensor assembly and a meter electronics. Relay switches 1002 are disposed between the first and second connector 1001, 1003. Accordingly, that is, in contrast to the signal switch 902 of meter electronics 920 described with reference to FIG. 9, the switching circuit 1000 is not part of the meter electronics. As can be appreciated, the switching circuit 1000 can therefore be coupled to an existing meter electronics without requiring a new meter electronics, such as the meter electronics 920 described with reference to FIG. 9. As shown in FIG. 10, the switching circuit 1000 is comprised of meter electronics side circuits and sensor assembly side circuits where a given circuit loop (including the meter electronics and sensor assembly not shown), such as a left pickoff circuit loop and a driver circuit loop, includes the relay switches 1002. If a circuit loop does not include the relay switches 1002, then the terms “meter electronics side” and “sensor assembly side” are not used for circuit loops that do not include a relay switch. An ‘X’ in a circuit label indicates that a circuit is on the meter electronics side of the relay switches 1002. Accordingly, the switching circuit 1000 is shown as including a meter electronics side left pickoff circuit XLPO + / - and a meter electronics side driver circuit XDRIVE + / -. Also shown is a right pickoff circuit loop RPO+ / - and a resistive temperature circuit loop(s) RTD-HI / LO / SENSE, which do not include relays. It should be appreciated that alternative switching circuits may include relays in the right pickoff circuit loop RPO+ / -, additional or alternative to the left pickoff circuit loop shown in FIG. 10. The relay switches 1002 are shown as being comprised of a first and second relay switch 1002a and 1002b, although more or fewer and / or alternative relay switches may be employed. As shown in FIG. 10, the relay switches 1002 temporarily swap the meter electronics side left pickoff circuit XLPO + / - with the meter electronics side driver circuit XDRIVE + / - by intercepting the 9-wire connection between the meter electronics and sensor assembly. This allows a drive signal from the meter electronics side drive circuit XDRIVE + / - to apply a forcing function via the sensor side left pickoff circuit LPO+ / - to the sensor assembly or, more specifically, a conduit or conduits, at the LPO location rather than solely at the driver location. Due to the LPO not being at a node of the twist mode, the twist mode may therefore be excited. With more particularity, a drive or first bend mode on the sensor assembly 510 illustrated in FIGS.5A and 6A by the symmetrically placed driver 518 in the center of the conduits 513, 513’. However, providing the drive signal to the driver 518 is not able to excite the twist mode shown in FIGS. 5B and 6B. This is because the driver 518 is located at a node of the twist mode at which the conduits 130, 130’ do not have motion. The LPO, RPO sensors 170l, 170r, however, may, for example, be located near the location of maximum motion of the conduits 130, 130’ in the twist mode, making it an ideal place to excite the twist mode. As shown in FIG. 10, swapping the left pickoff (LPO) circuit XLPO + / - with the driver circuit XDRIVE + / - is achieved with the relay switch 1002 controlled through the discrete outputs (DO) of the meter electronics indicated by CHA+ / -. However, using the DO is not necessary to control relays as other signals may be employed in other relays. Referring to FIG.10, when the DO is off, the sensor assembly 510 is in the drive mode shown in FIGS. 5A and 6A, but when the relay switches 1002 are activated, the drive signal from the meter electronics is routed to the left pickoff 170l on the sensor assembly 510 and the sensor signal from the driver 180 is routed to meter electronics via the meter electronics side left pickoff circuit XLPO + / -. It should be appreciated that the twist mode is excited and measured by changing the drive target for the drive signal and digital signal processing (DSP) filter parameters to the range expected for a given sensor assembly and pickoff sensors, such as the left and / or right pickoff sensors 517l, 517r, are measured. Accordingly, the frequency can be measured quickly, and the vibratory meter can be switched back to normal operation with minimal interruption. It should also be appreciated that the relay switches 1002 do not induce a zero to the vibratory meter and do not impact performance during first bend mode operation shown in FIGS. 5A and 6A. When the drive signal is provided to the left pickoff sensor, the single drive signal is provided to an asymmetrical location of the conduit. That is, the forcing function of the drive signal is provided at a location that is not at a center location of the conduit. Similarly, the sensor signals obtained from the driver and the right pickoff sensor are obtained from asymmetrical locations in that they are not equidistant from the center location of the conduit or respectively proximate end nodes. It should also be appreciated that being able to measure the instantaneous twist mode frequency allows for insights into countless characteristics of the process parameters including pressure, speed of sound, viscosity, etc. This may be especially useful because it does not require any alterations to current sensor assembly or meter electronics design, and it can be added to vibratory meters already in use. In addition, the foregoing explains that the two or more vibration modes may be simultaneously or alternately driven. For example, a meter electronics may drive the sensor assembly in a first bend mode for a time span, predetermined, conditional, or the like, and then switch to a second bend mode for a second time span. As can be appreciated, this ability to switch between various vibration modes can be beneficial in other ways, as the following discussion explains. Sensor crosstalk FIG. 11 shows a multi-sensor assembly system 1100 for operating a vibratory meter in two or more vibration modes. As shown in FIG.11, the multi-sensor assembly system 1100 is comprised of a first and second vibratory meter 1105a, 1105b. The first and second vibratory meter 1105a, 1105b are respectively shown as being comprised of a sensor assembly 1110a, 1110b communicatively coupled with a meter electronics 1120a, 1120b. It should be appreciated that the two sensor assemblies 1110a, 1110b may respectively be referred to as a first sensor assembly and a second sensor assembly. Similarly, the two meter electronics 1120a, 1120b may respectively be referred to as a first meter electronics and a second meter electronics. Alternatively, the two meter electronics 1120a, 1120b may be a single meter electronics that provides and / or receives sensor and / or drive signals to and / or from the two sensor assemblies 1110a, 1110b. Also shown in FIG. 11, is a processor 1121 illustrated as a dashed box, which may or may not be distinct from the two meter electronics 1120a, 1120b. For example, the processor 1121 may be a real and / or virtual processor, whether a single, multiple, distributed, and / or the like instance, that utilizes resources, such as memory, processing, signal processing, and / or the like, of the meter electronics 1120a, 1120b. When the first sensor assembly 1110a vibrates in a vibration mode, such as a first vibration mode, the vibration mode may inadvertently couple to the second sensor assembly. That is, the first sensor assembly 1110a can induce a particular vibration mode in the second sensor assembly. Similarly, the second sensor assembly 1110b can induce a particular vibration mode in the first sensor assembly. When the two sensor assemblies 1110a, 1110b are being driven in at or about the same frequencies, crosstalk or, with more particularity, vibration mode crosstalk can occur. The vibration mode crosstalk can occur between any two sensor assemblies that are mechanically coupled together, directly or via intervening structures, such as piping. For example, although the first and second sensor assembly 1110a, 1110b are shown as fluidly connected in series, alternative multi-sensor assembly systems may employ parallel and / or series arrangements of their sensor assemblies. The vibration mode crosstalk can cause performance issues, such as inaccurate measurement values, or other undesirable results. As can be appreciated, preventing two vibratory meters from operating at the same frequency can prevent such undesirable results. As will be described in more detail below, the processor 1121 may be configured to operate the vibratory meters in two or more vibration modes. As discussed above, multiple vibration modes may be driven in a sensor assembly, such as the sensor assemblies 10, 510 described with reference to FIGS. 1 and 2, and FIGS.5 and 6. For example, the first and second bend mode may be induced by the meter electronics 20, 920 described with reference to FIGS. 1, 2, and 9. The first twist mode can be induced by the meter electronics 920 described with reference to FIG. 9. With more particularity, a “nominal configuration” can be employed to drive the first and second out of phase bend mode and a “twist configuration” can be used to drive the twist mode. The following illustrates the effect of the twist configuration on the FRFs of the sensor assembly. Frequency response functions FIG. 12 shows an aggregate frequency response function (“FRF”) graph 1200 illustrating FRFs corresponding to the nominal and twist configurations of the meter electronics 920. As shown in FIG. 12, the aggregate FRF graph 1200 includes FRF plots 1230. The FRF plots 1230 include a first FRF plot 1230a, a second FRF plot 1230b, a third FRF plot 1230c, and a fourth FRF plot 1230d. Each of the first through fourth FRF plots 1230a-1230d correspond to a configuration of the meter electronics 920 and a transducer pair used for an FRF ratio. As shown in FIG.12, the FRF ratio is a “Velocity / excitation force” ratio. A legend 1240 illustrates the various configuration and FRF ratios of the FRF plots 1230. As shown in FIG. 12, the configurations of the meter electronics 920 may be “nominal” and “twist.” The “nominal” configuration refers to the drive signal being provided to the driver 180 of the sensor assembly 10. The “twist” configuration refers to the drive signal being provided to the LPO sensor 170l. The FRF ratios illustrate which transducer receives the driver signal and which is used for the “velocity” value in an FRF ratio. As shown in FIG.11, the FRF ratios include “LPO / DRV”, “RPO / DRV”, “DRV / LPO”, and “RPO / LPO.” The “LPO / DRV” label indicates that the “velocity” is determined from the LPO sensor 170l and the drive signal is provided to the driver 180. This is consistent with the “nominal configuration” of the meter electronics 920, which provides a drive signal to the driver 180. As can be appreciated, in the “nominal configuration,” the meter electronics 920 may determine the “velocity” of the FRF ratio based on either the LPO or RPO signal. Accordingly, the legend 1240 also includes a “Nominal – RPO / DRV” line. As can be appreciated, the first FRF plot 1230a corresponds to the nominal configuration with an LPO / DRV FRF ratio and the second FRF plot 1230b corresponds to the nominal configuration with an RPO / DRV FRF ratio. Accordingly, the first and second FRF plots 1230a, 1230b correspond to the nominal configuration where the numerator of the FRF ratio is based on the LPO signal or the RPO signal. The third FRF plot 1230c corresponds to the meter electronics 920 being in a twist configuration, where the drive signal is provided to the LPO sensor 170l, and the driver 180 provides a sensor signal that is used to determine the “velocity” of the FRF ratio. The fourth FRF plot 1230d also corresponds to the twist configuration of the meter electronics 920, but the velocity of the FRF ratio is determined based on the RPO signal provided by the RPO sensor 170r. As can be appreciated, the LPO sensor 170l is not shown as providing a sensor signal when the meter electronics 920 is in the twist configuration, which may be due to the LPO sensor 170l being switched to the drive signal. The FRF plots 1230 shows that a transducer not positioned at a node of a given normal mode can measure and / or excite the given normal mode. So, in a sensor assembly having a centrally located driver with two symmetrically offset pickoff sensors, the centrally located driver is at a node of the first order twist mode. Hence, a mostly flat response with a very narrow response at about 520 Hz is observed when the driver DRV is a numerator or denominator of the FRF ratio. Conversely, when the left pickoff LPO provides the forcing function and the right pickoff RPO measures the velocity, the twist mode is evident at the same frequency. The FRF plots 1230 also show, for the characterized sensor assembly, that the magnitudes of the first order bend mode are essentially the same at the right pickoff sensor RPO for either the “nominal” or “twist” configuration of the drive circuit. This may or may not be true for other sensor assemblies. Regardless, the fundamental frequency of the first bend mode is a structurally specific frequency that can be excited when a meter electronics is in a twist or bend mode configuration as described above with reference to FIGS. 9 and 10. As a result, a density value is not dependent on whether the first bend mode is excited by the driver or the LPO. Accordingly, the same calibration factors can be used to determine density when the drive signal is provided to the left pickoff sensor LPO or the driver DRV. Additionally, the “switching” between the left pickoff sensor LPO and the driver DRV only affects the ability of the drive circuit to induce the twist mode. That is, the first order bend mode may have a temporally constant amplitude if the drive signal is at a fundamental frequency of the first order bend mode even if the drive signal is provided to the LPO sensor. Therefore, the drive circuit may be unaffected in that the RPO sensor may measure an amplitude of the bend modes and / or the twist modes. As can also be appreciated from the FRF plots 1230, damping is present at the twist mode frequency, which can determine how quickly an excited vibration mode will settle out after excitation is stopped. Accordingly, an amplitude of a twist mode driven by the “twist” configuration could settle relatively quickly after switching back to the “nominal” configuration. It should also be appreciated that all of the normal modes can be excited when the drive circuit is in the “twist” configuration, such as that shown in FIG.9. That is, as a frequency of the drive signal provided to the LPO sensor 170l is swept from 0 Hz to 2000 Hz, the first and second bend modes as well as the first and second twist modes are excited. This is due to the LPO and RPO sensors 170l, 170r not being at nodes of the bend or twist modes. In addition, although the LPO sensor 170l is not at a central location of the conduits 130, 130’ and therefore a forcing function is applied at an asymmetrical location relative to the central node of the first twist mode, the central node of the first twist mode is at the central location corresponding to the driver 180, as the following discussion demonstrates. FIG. 13 shows a graph 1300 illustrating sensor signals plotted in a time domain when an asymmetrical forcing function is applied to a conduit. As shown in FIG. 13, the graph 1300 includes a time axis 1310 and a magnitude axis 1320 respectively in units of milli-seconds (ms) and volts (V), although any suitable units may be employed. Also shown are sensor signal plots 1330 comprising an RPO pickoff sensor signal plot 1330a and a driver sensor signal plot 1330b. The term “driver sensor signal plot” refers to a driver connected to a meter electronics in a “twist mode” configuration so as to provide a sensor signal to the meter electronics, such as the “twist mode” configuration described above with reference to FIG. 9. A magnitude of the sensor signal plots 1330 indicates an amount of physical displacement of the conduit at the location of the RPO sensor and the driver. As can be appreciated, the RPO pickoff sensor signal plot 1330a indicates a displacement of the conduit at the RPO sensor location. The magnitude of the RPO pickoff sensor signal plot 1330a ranges from about 1.5 to -1.75 volts. However, the magnitude of the driver sensor signal plot 1330b ranges from 0 to about 0.2 volts. That is, the magnitude of the driver sensor signal 1330b indicates that there is about or effectively zero displacement of the conduit at the driver location of the conduit. Accordingly, it should be appreciated that although the forcing function is applied to the conduit at an asymmetrical location, the first twist mode is not distorted by, for example, a near static displacement. The twist mode can be used to predict a calibration factor or constant, such as the FCF described above with reference to Equation [1]. With more particularity, the FCF may be correlated with a stiffness of a conduit. A magnitude of the phase difference between the periodic amplitudes of the two pickoffs is related to the twist motion of the tubes induced by a Coriolis force that is generated by the motion of the material through the oscillating conduits in a vibratory meter. The extent of the twist motion, in turn, will be dictated by the stiffness of the tube geometry to this induced twisting motion. Hence, the FCF will be related to the stiffness of the conduit geometry to this first twist mode motion. As discussed above, the FCF relates the mass flow through the Coriolis meters to the magnitude of the phase difference between the periodic amplitudes at the two pickoffs. Determining the FCF can require a significant amount of time. In addition, some vibratory meters must meet stringent flow rate accuracy. Accordingly, being able to predict which vibratory meter, manufactured but not yet calibrated, may meet the stringent requirement can ensure that calibration time is not consumed on a vibratory meter that will not meet the requirement. In addition, determining an FCF without requiring the calibration could reduce manufacturing costs by a significant amount. By driving a first twist mode as described above, or by other techniques, an additional measurement of this twist mode frequency at the diagnostic stand to better predict FCF for a vibratory meter. This additional measurement at a diagnostic stand may be relatively easy to implement and may not significantly increase testing time. The elimination of FCF calibration for most units during the calibration stage will reduce the time for calibration significantly, without significantly adding additional measurement time at the diagnostic stand. This is above and beyond any possible savings that may be attained by using the additional twist mode frequency measurement to sort and bin the meters appropriately to increase their probability of passing different (as per the customer order) mass flow error specifications. It should be appreciated that the foregoing discussion of multiple modes in a vibratory meter may depend somewhat on a conduit that has no deposits, erosion, corrosion, and / or the like. In addition, it should also be appreciated that the different vibration modes can be used for meter verification at about their respective frequency ranges, as the following discussion illustrates. Meter verification Meter verification is a process that can verify whether or not vibration parameters of a sensor assembly have been affected by changes affecting the sensor assembly. Exemplary changes that affect a sensor assembly include erosion, corrosion, deposits, etc. Performing meter verification in two or more mode can provide additional diagnostic information about a vibratory meter. This information can be used on its own in the manner currently used in traditional meter verification. It could also be used in conjunction with the meter verification information about the traditional drive mode. The description below shows how meter verification can be used in two vibration modes to identify and track the characteristic stiffness of each driven vibration mode. FIG. 14 shows a drive signal frequency spectrum graph 1400. As shown in FIG. 14, the drive signal frequency spectrum graph 1400 includes a frequency axis 1410 in units of hertz (Hz) and a drive signal amplitude axis 1420 that is unitless, but may be in units of volts, current, velocity (correlated), etc. The frequency axis 1410 ranges from zero to 800 hertz although any suitable range can be employed. The drive signal frequency spectrum graph 1400 includes a first drive signal plot 1430a and a second drive signal plot 1430b. As can be appreciated, the first and second drive signal plots 1430a, 1430b are in the frequency domain. As can also be appreciated, the first and second drive signal plots 1430a, 1430b are comprised of sinusoidal or tone components. With more particularity, the first and second drive signal plots 1430a, 1430b include a resonant frequency drive component and four offset test tones. The resonant frequency drive component may be generated based on a feedback loop that uses a fundamental frequency of a corresponding vibration mode. For example, the first and second drive signal plots 1430a, 1430b may respectively include a resonant frequency drive component that is based on a sensor signal that includes a fundamental frequency of a first vibration mode and second vibration mode. Accordingly, the first and second drive signal plots 1430a, 1430b may respectively correspond to a first vibration mode and a second vibration mode. As discussed above, a first vibration mode may be a first bend mode and a second vibration mode may be a second bend mode. FIG. 15 shows frequency response function 1500 for verifying a vibratory meter operating in two or more vibration modes. As shown in FIG. 15, the frequency response function 1500 is comprised of a first frequency response graph 1500a and a second frequency response graph 1500b. The first and second frequency response graphs 1500a, 1500b are respectively comprised of frequency axes 1510a, 1510b and magnitude axes 1520a, 1520b. The frequency axes 1510a, 1510b range from zero to 1000 hertz (Hz), although any suitable range and units may be employed. The magnitude axes 1520a, 1520b are response-to-forcing function ratios (X / F) and are not shown with units but may be in any suitable unit. The magnitude axes 1520a, 1520b range from 10-9to 10-4, although any suitable range or ranges may be employed. The first and second frequency response graphs 1500a, 1500b also include a frequency response function plot 1530. As can be appreciated, the frequency response function plot 1530 include a first, second, and third fundamental frequency peak 1530a, 1530b, 1530c indicated as “Mode 1”, “Mode 2”, and “Mode 3.” That is, each of the first, second, and third fundamental frequency peak 1530a, 1530b, 1530c respectively correspond to a first, second, and third vibration mode. The first vibration mode may be a first bend mode, the second vibration mode may be a first twist mode, and the third vibration mode may be a second bend mode, although more or fewer and alternative vibration modes and fundamental frequency peaks may be employed. The frequency response function plot 1530 may be obtained by sweeping a frequency of a model of a conduit, such as the three degree of freedom model 704 described with reference to FIG. 7. That is, the three degree of freedom model 704 described with reference to FIG. 7 can be characterized by its frequency response function (FRF). As shown in FIG. 15, the frequency response function plot 1530 provides an FRF of each pickoff LPO, RPO shown in FIG. 7 to harmonic driver excitation from 0 Hz (DC or static) to 1,000 Hz. With more specificity, the frequency response function plot 1530 includes an LPO / Driver FRF plot labeled as “LPO” and the RPO / Driver FRF labeled as “RPO”, which are superimposed. The frequency response function plot 1530 also includes a first mode peak 1530a, a second mode peak 1530b, and a third mode peak 1530c, which respectively correspond to modal or fundamental frequencies of the first through third vibration modes. The frequency response function plot 1530 is shown in both the first and second frequency response graphs 1500a, 1500b. It should be appreciated that a perfectly built and balanced vibratory meter should not have a pickoff response of Mode 2 from driver excitation and thus would not show up on this figure. An imbalance was provided to a model to visualize Mode 2 on the frequency response function plot 1530. Also shown respectively in the first and second frequency response graphs 1500a, 1500b is a first and second single mode-single degree of freedom fits 1540a, 1540b. The first and second single mode-single degree of freedom fits 1540a, 1540b are fitted to the frequency response function plot 1530 according to their respective vibration modes indicated by “Mode 1” and “Mode 3.” The first and second single mode-single degree of freedom fits 1540a, 1540b are shown as superimposed with the frequency response function plot 1530. The first and second single mode-single degree of freedom fits 1540a, 1540b are fitted to the frequency response function plot 1530 and represent a meter verification for the given mode whose parameters are being estimated. The first and second single mode-single degree of freedom fits 1540a shows a meter verification fit for the first vibration mode indicated by “Mode 1” and the second single mode-single degree of freedom fit 1540b shows a meter verification fit for the third vibration mode indicated by “Mode 3.” Meter verification may track a change in static stiffness, or other structural characteristics, of a conduit, such as the conduit 130, 130’ described above, in the first bend mode, which may be referred to as a drive mode. As shown in FIG. 15, the first bend mode is the first vibration mode indicated by “Mode 1.” The stiffness value may be derived from the value of the single mode single degree of freedom fit of the drive mode where the first single mode single degree of freedom fit 1440a crosses the magnitude axis 1420a at 0 Hz, which are indicated by stars. As can be appreciated, the first and second single mode-single degree of freedom fits 1440a, 1440b for first vibration mode “Mode 1” and the third vibration mode “Mode 3” are different values. These values can and will change if the structure itself changes in a way that affects stiffness or other meter parameter values. As can be appreciated, a meter electronics may provide one or more drive signals according to the first and second drive signal plots 1430a, 1430b to a sensor assembly to obtain the first and / or second single mode single degree of freedom fits 1540a, 1540b, or the like, to determine the stiffness or other sensor assembly properties for detecting if a change has occurred. It should be appreciated from the discussion of FIG.15 that obtaining a fit at or about the fundamental frequency of each mode may not require sweeping an entire frequency range encompassing the fundamental frequencies. For example, as can be appreciated from comparing FIGS.14 and 15, a sectioned or piece wise fit may be obtained with four FRF magnitudes at or about the fundamental frequencies. The following describes meter electronics that can obtain the described and other single mode fits. FIG.16 shows a block diagram of a vibratory meter 1605 including meter verification using two or more fundamental frequencies. As shown in FIG.16, the vibratory meter 1605 includes a meter electronics 1620 communicatively (e.g., electrically) coupled to a sensor 1610. The sensor assembly 1610 is comprised of two conduits 1613 although only one conduit is shown for clarity. The sensor assembly 1610 also includes an LPO sensor 1617l and an RPO sensor 1617r that are fixed to the two conduits 1613 to measure a relative displacement related parameter between the two conduits 1613. A centrally located driver 1618 is also shown fixed to the two conduits 1613. The LPO sensor 1617l, RPO sensor 1617r, and / or driver 1618 may be configured to receive a drive signal from and / or provide a sensor signal to the meter electronics 1620. The meter electronics 1620 includes a signal circuit 1621 configured to receive sensor signals, such as two sensor signals, from the sensor assembly 1610. The signal circuit 1621 is also configured to provide a drive signal to the sensor assembly 1610. The signal circuit 1621 may include switches, signal condition, signal processing, amplifiers, and / or the like that may be employed for signals provided to or from the sensor assembly 1610. For example, the signal circuit 1621 may include a switch that switches a drive signal from the driver 1618 to the LPO sensor 1617l and then provides a sensor signal from the driver 1618 to, for example, filters in the signal circuit 1621 for filtering. The meter electronics 1620 also includes a drive circuit 1622 that provides a drive signal to the sensor assembly 1610. The sensor assembly 1610 is communicatively coupled with and provides sensor signals to the meter electronics 1620. A demodulation filter 1624 receives the sensor signals from the sensor assembly 1610 and passes signals that are within a demodulation window or windows of the demodulation filter 1624. The signals passed by the demodulation filter 1624 are provided to an FRF estimation unit 1625. Notch filters 1626 also receives the sensor signal, which passes a resonant component to the drive circuit 1622 and a flow and density measurement module 1627, which can determine a fluid property value of a fluid. The sensor assembly 1610 receives the multi-tone drive signal from the meter electronics 1620 and provides the sensor signals to the meter electronics 1620 to characterize the sensor assembly 1610. The multi-tone drive signal is therefore an input to a frequency response of the sensor assembly 1610 and the sensor signal is an output of the frequency response of the sensor assembly 1610. By comparing the input and the output, the frequency response of the sensor assembly 1610 may be characterized. Further, an analytical solution may be formulated by, for example, fitting a curve to the characterization of the sensor assembly 1610. As the foregoing discussion illustrates, a vibration mode relationship (e.g., a ratio between fundamental frequencies and / or time-periods of two or more vibration modes, difference, etc.) between the two SDOF fits can provide more diagnostic information about the vibratory meter, in particular the sensor assembly, and how it may have changed. Because different modes have different vibration shapes, and therefore more or less bending action in different locations along the flow tube, meter verification in different modes may be more or less sensitive to erosion or other issues in different locations. For example, the first bend mode may have a significant amount of strain near the brace bar, therefore meter verification should be especially sensitive to erosion proximate the brace bar, while the first bend mode has no strain at the driver location and therefore may not pick up on changes that occurred there. Running meter verification in multiple modes may provide sensitivity to effects like erosion, corrosion, deposition, and / or the like, in various locations of the flow tube where the given mode has mode strain. Methods FIG. 17 shows a method of operating a vibratory meter in two or more vibration modes. As shown in FIG.17, the method 1700, in step 1710, vibrates, with a drive signal, a sensor assembly in a first vibration mode. In step 1720, the method 1700 vibrates, with the drive signal, the sensor assembly in a second vibration mode. It should be appreciated that nodes of the first vibration mode and nodes of the second vibration mode may be symmetrically located on a conduit of the sensor assembly. Additionally, or alternatively, the sensor assembly can be asynchronously vibrated in the first vibration mode and the second vibration mode. It should also be appreciated from the foregoing discussion that the sensor assembly further comprises a driver symmetrically disposed on a conduit of the sensor assembly. The driver being symmetrically disposed on the conduit of the sensor assembly comprises the driver being disposed equidistance between brace bars coupled to the conduit. The brace bars can define end nodes of the first vibration mode and the second vibration mode. Additionally, or alternatively, the driver being symmetrically disposed on the conduit may comprise the driver being disposed at a node of the nodes of the second vibration mode. The driver being symmetrically disposed on the conduit of the sensor assembly may also, in addition or alternatively, comprise the driver being symmetrically disposed between two or more pickoff sensors disposed on the conduit of the sensor assembly. As can be appreciated, the driver symmetrically disposed on the conduit of the sensor assembly may comprise a single driver affixed to a center of the conduit. The sensor assembly may further comprise a pickoff sensor disposed on the conduit of the sensor assembly. The drive signal may be provided to one of the driver and the pickoff sensor. The method 1700 may vibrate the sensor assembly in the first vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the first vibration mode. Additionally, or alternatively, the method can vibrate the sensor assembly in the second vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the second vibration mode. The first vibration mode may be a first bend mode and the second vibration mode may be one of a second bend mode and a first twist mode. The drive signal can apply a forcing function to the conduit at one of a symmetric location and an asymmetric location of the conduit. The asymmetric location of the conduit can be a location of an antinode of the first vibration mode and the symmetric location of the conduit is a location of a node of the second vibration mode, although any suitable locations may be employed such as proximate the antinode of the vibration mode, etc. Vibrating, with the drive signal, the sensor assembly in the first vibration mode and the second vibration mode can comprise providing the drive signal to a single transducer disposed on the conduit. When the method 1700 vibrates a vibratory meter asynchronously, the method 1700 may further comprise coordinating between the vibratory meter and a second vibratory meter to asynchronously vibrate the sensor assembly with the first vibration mode and second vibration mode. Coordinating between the vibratory meter and the second vibratory meter can comprise determining if a frequency related calibration constant value of the vibratory meter is substantially the same as a frequency related calibration constant value of the second vibratory meter. The frequency related calibration constant may relate a fundamental frequency of a vibration mode with a density value of a material contained by a conduit of the sensor assembly. Coordinating between the vibratory meter and the second vibratory meter comprises causing the vibratory meter to vibrate in the first vibration mode if the second vibratory meter is vibrating in the second vibration mode. FIG. 18 shows a method 1800 of operating a vibratory meter in two or more vibration modes. As shown in FIG.18, the method 1800 comprises, in step 1810, switching a drive signal from a first transducer coupled to a conduit of a sensor assembly to a second transducer coupled to the conduit of the sensor assembly. As can be appreciated, the method may be performed by a vibratory meter, such as the vibratory meter 905 described with reference to FIG.9, although any suitable vibratory meter, apparatus, system, and / or the like may be employed. In the method 1800, similar to the method 1700 described above, the first transducer is located at a node of the second vibration mode and a second transducer located away from the node of the second vibration mode. The first transducer may be a driver and the second transducer may be a pickoff sensor. The pickoff sensor can be one of a left pickoff sensor and a right pickoff sensor coupled to the conduit of the sensor assembly, although any suitable configuration of the pickoff sensors may be employed. The sensor assembly may further comprise a third transducer, wherein the first transducer is symmetrically disposed between the second transducer and the third transducer. The first transducer being symmetrically disposed between the second transducer and the third transducer may comprise the first transducer being symmetrically equidistant between the second transducer and the third transducer. The method 1800 may further comprise vibrating, with a drive circuit, a sensor assembly of the vibratory meter in a first vibration mode and vibrating, with the drive circuit, the sensor assembly of the vibratory meter in a second vibration mode. The first vibration mode can be a first bend mode and the second vibration mode can be a twist mode. Switching the drive signal may comprise switching the drive signal with one or more relay switches disposed between a signal generator and the sensor assembly. The method 1800 may further comprise receiving with the one or more relay switches a signal commanding the one or more relay switches to switch the drive signal. Additionally, or alternatively, the method 1800 may further comprise switching the drive signal from the second transducer coupled to the conduit of the sensor assembly to the first transducer coupled to the conduit of the sensor assembly. Switching the drive signal from the first transducer to the second transducer and switching the drive signal from the second transducer to the first transducer can comprise asynchronously switching the drive signal from the first transducer to the second transducer and switching the drive signal from the second transducer to the first transducer. The method 1800 may further comprise switching a sensor signal from the second transducer coupled to the conduit of a sensor assembly to the first transducer coupled to the conduit of the sensor assembly. Additionally, or alternatively, switching the drive signal and switching the sensor signal can comprise contemporaneously switching the drive signal and switching the sensor signal. That is, the two signals can be switched at the same time without being multiplexed together in the frequency domain and without a “no signal” gap between the sensor signal and the drive signal. As can be appreciated from the above discussion referring to, for example, FIG. 12, the vibratory meter may be operated in more than two modes. By way of illustration, the vibratory meter may be operated in a first bend mode, a first twist mode, and a second bend mode. In this example, the three modes could be excited by the meter electronics capable of applying a forcing function at a fundamental frequency of each of the three modes at a non-nodal location on the conduit, such as an asymmetric location of the conduit where the nodes are symmetrically located on the conduit. The meter electronics 920, 1020 described above are able to provide drive signals at the fundamental frequencies and non-nodal locations of the first and second bend mode and the first twist mode, as is explained above. Additionally, or alternatively, the forcing function could be applied to a non- nodal location of an excited mode that is also a nodal location of a non-excited mode. For example, applying a forcing function at a center location of a conduit of a symmetrical sensor assembly, such as to the driver 180, 518 of the sensor assemblies 10, 510 described with reference to FIGS.1 and 5A-5C, at a fundamental frequency of the first order bend mode can excite the first bend mode, but will not excite the first twist mode. In this example, the first twist mode can be asynchronously excited by switching the drive signal having a sinusoidal frequency at a fundamental frequency of the first twist mode to an asymmetric location, such as to the LPO sensor 170l, 517l described above. The foregoing provides a vibratory meter 5, 905, a multi-sensor assembly system 1100, and methods 1700, 1800. As is explained above, simple sensor assembly designs, such as those that utilize a single driver and two pickoff sensors, can be operated in two or more vibration modes. That is, complex circuits, such as balancing circuits, sensor assemblies that require two or more drivers, and / or the like may not be required. Accordingly, routines, such as those described above, can be programmed into vibratory meters that do not employ such complex designs. The relatively simple designs may correspond to vibratory meters that are already employed in the field. As a result, a software upgrade can be used to operate the vibratory meters in the two or more vibration modes. By operating the vibratory meter in two or more vibration modes, there are various advantages of the two or more vibration modes. For example, a more sensitive mode, such as a first bend mode, can be employed when sensitivity is desired in a measurement, such as those that are near a measurement threshold. Additionally, or alternatively, a second vibration node that is more stable may be employed in, for example, applications that require more stable measurements of a fluid flow. For example, a second bend mode can be employed at a higher frequency than the first bend mode. It should be appreciated that twist modes can also be employed. For example, a twist mode may be more suitable for determining certain process-related parameters. The twist mode can be applied to the sensor assembly at a non-node location of the twist mode, such as a pickoff sensor location. The detailed descriptions of the above embodiments are not exhaustive descriptions of all embodiments contemplated by the inventors to be within the scope of the present description. Indeed, persons skilled in the art will recognize that certain elements of the above-described embodiments may variously be combined or eliminated to create further embodiments, and such further embodiments fall within the scope and teachings of the present description. It will also be apparent to those of ordinary skill in the art that the above-described embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the present description. Thus, although specific embodiments are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the present description, as those skilled in the relevant art will recognize. The teachings provided herein can be applied to other meter electronics, vibratory meters, and methods for operating a vibratory meter in two or more vibration modes and not just to the embodiments described above and shown in the accompanying figures. Accordingly, the scope of the embodiments described above should be determined from the following claims.

Claims

We claim:

1. A method of operating a vibratory meter in two or more vibration modes, the method comprising: vibrating, with a drive signal, a sensor assembly in a first vibration mode; and vibrating, with the drive signal, the sensor assembly in a second vibration mode; wherein nodes of the first vibration mode and nodes of the second vibration mode are symmetrically located on a conduit of the sensor assembly.

2. The method of claim 1, wherein the sensor assembly further comprises a driver symmetrically disposed on a conduit of the sensor assembly.

3. The method of claim 2, wherein the driver being symmetrically disposed on the conduit of the sensor assembly comprises the driver being disposed equidistance between brace bars coupled to the conduit.

4. The method of claim 3, wherein the brace bars define end nodes of the first vibration mode and the second vibration mode.

5. The method of claim 4, wherein the driver being symmetrically disposed on the conduit comprises the driver being disposed at a node of the nodes of the second vibration mode.

6. The method of claim 2, wherein the driver being symmetrically disposed on the conduit of the sensor assembly comprises the driver being symmetrically disposed between two or more pickoff sensors disposed on the conduit of the sensor assembly.

7. The method of claim 2, wherein the driver symmetrically disposed on the conduit of the sensor assembly is comprised of a single driver affixed to a center of the conduit.

8. The method of claim 2, wherein the sensor assembly further comprises a pickoff sensor disposed on the conduit of the sensor assembly, wherein the drive signal is provided to one of the driver and the pickoff sensor.

9. The method of claim 1, wherein: vibrating the sensor assembly in the first vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the first vibration mode; and vibrating the sensor assembly in the second vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the second vibration mode.

10. The method of claim 1, wherein the first vibration mode is a first bend mode and the second vibration mode is one of a second bend mode and a first twist mode.

11. The method of claim 1, wherein the drive signal applies a forcing function to the conduit at one of a symmetric location and an asymmetric location of the conduit.

12. The method of claim 11, wherein: the asymmetric location of the conduit is a location of an antinode of the first vibration mode; and the symmetric location of the conduit is a location of a node of the second vibration mode.

13. The method of claim 1, wherein vibrating, with the drive signal, the sensor assembly in the first vibration mode and the second vibration mode comprises providing the drive signal to a single transducer disposed on the conduit.

14. A vibratory meter (5) configured to operate in two or more vibration modes, the vibratory meter comprising: a sensor assembly (10) comprising a conduit (130, 130’) and a driver (180) disposed on the conduit; and a meter electronics (20) communicatively coupled to the sensor assembly (10), the meter electronics (20) being configured to perform a method according to one of the foregoing claims 1 to 13.

15. A method of operating a vibratory meter in two or more vibration modes, the method comprising: vibrating, with a drive signal, a sensor assembly in a first vibration mode; and vibrating, with the drive signal, the sensor assembly in a second vibration mode; wherein the sensor assembly is asynchronously vibrated in the first vibration mode and the second vibration mode.

16. The method of claim 15, wherein: vibrating the sensor assembly in the first vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the first vibration mode; and vibrating the sensor assembly in the second vibration mode comprises providing the drive signal to the sensor assembly at a fundamental frequency of the second vibration mode.

17. The method of claim 15, wherein the first vibration mode is a first bend mode, and the second vibration mode is one of a second bend mode and a first twist mode.

18. The method of claim 15, wherein a driver is symmetrically disposed on a conduit of the sensor assembly.

19. The method of claim 18, wherein the driver being symmetrically disposed on the conduit of the sensor assembly comprises the driver being symmetrically disposed between two or more pickoff sensors disposed on the conduit of the sensor assembly.

20. The method of claim 15, wherein the drive signal applies a forcing function to a conduit of the sensor assembly at one of a symmetric location and an asymmetric location of the conduit.

21. The method of claim 20, wherein: the asymmetric location of the conduit is a location of an antinode of the first vibration mode; and the symmetric location of the conduit is a location of a node of the second vibration mode.

22. The method of claim 15, wherein vibrating, with the drive signal, the sensor assembly in the first vibration mode and the second vibration mode comprises providing the drive signal to a single transducer disposed on a conduit of the sensor assembly.

23. The method of claim 15, further comprising coordinating between the vibratory meter and a second vibratory meter to asynchronously vibrate the sensor assembly in the first vibration mode and second vibration mode.

24. The method of claim 23, wherein coordinating between the vibratory meter and the second vibratory meter comprises determining if a frequency related calibration constant value of the vibratory meter is substantially the same as a frequency related calibration constant value of the second vibratory meter.

25. The method of claim 24, wherein the frequency related calibration constant relates a fundamental frequency of a vibration mode with a density value of a material contained by a conduit of the sensor assembly.

26. The method of claim 23, wherein coordinating between the vibratory meter and the second vibratory meter comprises causing the vibratory meter to vibrate in the first vibration mode if the second vibratory meter is vibrating in the second vibration mode.

27. A vibratory meter (5, 1105a) for operating in two or more vibration modes, the vibratory meter (5, 1105a) comprising: a sensor assembly (10, 1110a); anda meter electronics (20, 1120a) communicatively coupled with the sensor assembly (1110a), the meter electronics (1120a) being configured to perform a method according to one of the foregoing claims 15 to 26.

28. A system (1100) for vibrating a vibratory meter in two or more vibration modes, the system (1100) comprising: a first vibratory meter (1105a) configured to operate in the two or more vibration modes; a second vibratory meter (1105b) configured to operate in at least one of the two or more vibration modes; and a processor (1121) configured to perform a method according to one of the foregoing claims 15 to 26.

29. The system (1100) of claim 28, wherein the second vibratory meter (1105b) being configured to operate in at least one of the two or more vibration modes comprises the second vibratory meter (1105b) being configured to operate in the two or more vibration modes.

30. The system (1100) of claim 28, wherein the processor (1121) is part of at least one of a meter electronics (1120a) of the first vibratory meter (1105a) and a meter electronics (1120b) of the second vibratory meter (1105b).

31. The system (1100) of claim 28, wherein the processor (1121) is configured to cause the second vibratory meter (1105b) to vibrate at a vibration mode that is different than a vibration mode of the first vibratory meter (1105a).

32. A method of operating a vibratory meter in two or more vibration modes, the method comprising switching a drive signal from a first transducer coupled to a conduit of a sensor assembly to a second transducer coupled to the conduit of the sensor assembly.

33. The method of claim 32, wherein the first transducer is located at a node of a second vibration mode and the second transducer located away from the node of the second vibration mode.

34. The method of claim 32, wherein the first transducer is a driver and the second transducer is a pickoff sensor.

35. The method of claim 34, wherein the pickoff sensor is one of a left pickoff sensor and a right pickoff sensor coupled to the conduit of the sensor assembly.

36. The method of claim 32, further comprising a third transducer, wherein the first transducer is symmetrically disposed between the second transducer and the third transducer.

37. The method of claim 36, wherein the first transducer being symmetrically disposed between the second transducer and the third transducer comprises the first transducer being symmetrically equidistant between the second transducer and the third transducer.

38. The method of claim 32, further comprising vibrating, with a drive circuit, a sensor assembly of the vibratory meter in a first vibration mode; and vibrating, with the drive circuit, the sensor assembly of the vibratory meter in a second vibration mode.

39. The method of claim 38, wherein the first vibration mode is a first bend mode and the second vibration mode is a twist mode.

40. The method of claim 38, wherein switching the drive signal comprises switching the drive signal with one or more relay switches disposed between a signal generator and the sensor assembly.

41. The method of claim 40, further comprising receiving with the one or more relay switches a signal commanding the one or more relay switches to switch the drive signal.

42. The method of claim 32, further comprising switching the drive signal from the second transducer coupled to the conduit of the sensor assembly to the first transducer coupled to the conduit of the sensor assembly.

43. The method of claim 42, wherein switching the drive signal from the first transducer to the second transducer and switching the drive signal from the second transducer to the first transducer comprises asynchronously switching the drive signal from the first transducer to the second transducer and switching the drive signal from the second transducer to the first transducer.

44. The method of claim 32, further comprising switching a sensor signal from the second transducer coupled to the conduit of a sensor assembly to the first transducer coupled to the conduit of the sensor assembly.

45. The method of claim 44, wherein switching the drive signal and switching the sensor signal comprises contemporaneously switching the drive signal and switching the sensor signal.

46. A vibratory meter (905) for operating in two or more vibration modes, the vibratory meter (905) comprising: a sensor assembly (910); and a meter electronics (920) communicatively coupled with the sensor assembly (910), the meter electronics (920) being configured to perform a method according to one of the foregoing claims 32 through 45.

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