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`Exhibit B
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`Case 6:12-cv-00799-JRG Document 120-2 Filed 03/06/14 Page 2 of 11 PageID #: 3405
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`C.A. No. 6:12-cv-00799-LED
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`JURY TRIAL DEMANDED
`
`IN THE UNITED STATES DISTRICT COURT
`FOR THE EASTERN DISTRICT OF TEXAS
`TYLER DIVISION
`
`§
`INVENSYS SYSTEMS, INC.,
`§
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`
`§
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`Plaintiff,
`§
`v.
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`§
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`§
`EMERSON ELECTRIC CO. and
`§
`MICRO MOTION INC., USA,
`§
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`§
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`Defendants.
`§
`and
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`§
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`§
`MICRO MOTION INC., USA,
`§
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`§
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`Counterclaim-Plaintiff,
`§
`v.
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`§
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`§
`INVENSYS SYSTEMS, INC.,
`§
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`
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`Counterclaim-Defendant. §
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`
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`TECHNICAL TUTORIAL SCRIPT FOR PLAINTIFFS’ PATENTS
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`Plaintiff Invensys Systems, Inc. respectfully submits this technology tutorial covering the
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`background of the technology that is the subject of the patents in this case. The first portion of
`this tutorial provides an overview of the technology related to the Invensys patents and the
`second provides an overview of the technology related to Micro Motion and Emerson’s patents.
`
`
`
`The technology claimed in Invensys’ patents relates to Coriolis flowmeters in general but
`more specifically to two primary aspects: (1) a digitally generated drive signal used by the driver
`to oscillate flowtubes and (2) improved measurement and response capabilities to deal with
`system disturbances by using advanced digital signal processing. The patented improvements
`solved at least one major problem that perplexed the Coriolis flowmeter industry for decades—
`two phase flow.
`
`
`Flowmeters, as the name implies, primarily are used to measure the flow rate of a
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`material flowing through a pipe or conduit. The flow rate can be measured in terms of volume or
`mass of the material flowing through the pipe or conduit. The type of flowmeter covered by all
`of the patents in this case is known as a Coriolis flowmeter.
`
`
`
`Coriolis flowmeters come in many different shapes and sizes to meet the needs of a vast
`array of applications and industries, including oil and gas, pharmaceuticals, chemicals and
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`petrochemicals, food and hygiene products, just to name a few. The market for Coriolis
`flowmeters has been steadily growing and is projected to continue to grow. The worldwide
`market revenue for Coriolis flowmeters is currently more than $800 million per year.
`
`
`
`In part, the success and market growth of for Coriolis flowmeters is because that they are
`the only type of flowmeters that measure the mass of the material flowing through a pipe at a
`given point in time. For many applications, measuring the mass is greatly preferable to
`volumetric measuring. Coriolis flowmeters can also measure other properties, such as density,
`which is sometimes necessary, but measuring the mass of the material flowing through the pipe,
`or mass flow rate, is the primary function of the Coriolis flow meter. The mass flow rate is the
`specific mass flow at a given point in time. In addition to the mass flow rate, Coriolis flowmeters
`can also keep running totals of the amount of mass that flows through a pipe during specified
`periods of time. These measurements are known as total mass flow, instead of a specific mass
`flow rate.
`
`
`
`With that background, we’ll spend a minute or two discussing the basic components of
`Coriolis flowmeters and explain the Coriolis effect before diving into an overview of the
`patented technology. Here is a stylized depiction of a Coriolis flowmeter. The liquid being
`measured runs through the pipe at the top. When the liquid reaches the flowmeter, it is redirected
`away from the pipe, through the flowmeter, and then back into the pipe. A control and
`measurement system is connected to the flowtube to control the entire process of oscillating the
`tubes and taking measurements.
`
`
`
`The basic components of Coriolis flowmeters are a pair of flowtubes, through which the
`liquid flows; a driver, which oscillates the flow tubes back and forth; sensors, which measure the
`oscillation (either based upon velocity or position); and an electronic control and measurement
`system. The Control and measurement system, taken as a whole, is often called the transmitter or
`controller. These terms are used interchangeably throughout the industry and the patents in suit.
`The control and measurement circuitry may be integrated into the flowmeter housing or it may
`be a stand-alone component that communicates with the driver and sensors remotely, as shown
`in this drawing. Alternatively, the control and measurement system or circuitry may be split into
`different locations. For example, some circuitry may be integrated into the housing while the rest
`is remote. Regardless of the configuration, the control and measurement system performs two
`primary functions. First, using the sensor signals, it measures or calculates the mass flow rate of
`the material flowing through the flowtubes. Second, the control and measurement system forms
`a drive signal that controls how the driver oscillates the flowtubes.
`
`
`
`The interaction between the driver, flowtubes, sensors, and control and measurement
`system is key to understanding how Coriolis flowmeters work and understanding the inventions
`described in the Invensys patents. In particular, we will focus on how the control and
`measurement systems forms drive signals to maintain oscillation of the flowtubes.
`
`
`As we mentioned, Coriolis flowmeters measure mass flow rate by directing fluid through
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`a pair of flowtubes that are oscillating back and forth. As we will discuss later, the mass flow rate
`is related to the how the tubes oscillate. So, if the flowtubes stop oscillating or the strength of
`vibration falls below a certain level, the flowmeter will stop working or become unreliable. Thus,
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`it is critical that the flowtubes continue to oscillate with sufficient strength so that accurate
`measurements can be made. We may refer to this strength of the oscillation as the amplitude.
`
`
`
`A simple analogy is a tuning fork used to tune a musical instrument. When you strike the
`tuning fork you provide energy to the fork and the fork begins to vibrate or oscillate. The
`oscillation of the fork results in a strong consistent tone. Over time, however, the strength of the
`oscillation dissipates and the tone weakens. At some point, the strength of the oscillation is too
`weak to hear and be useful to tune the musical instrument. Eventually the tuning fork will stop
`oscillating all together. Likewise, a disturbance, such as dampening the vibration prongs with
`your hand, can stop or reduce the strength of the oscillation. To keep the tuning fork ringing
`constantly, it must be struck regularly to maintain vibration, and it must be protected from any
`disturbance.
`
`
`
`Likewise, the Coriolis flowmeter needs its flowtubes to continue to oscillate with
`sufficient strength or amplitude to provide useful measurements. Thus, maintaining oscillation of
`the flowtubes over time and when faced with disturbances is critical to the operation of the
`flowmeter.
`
`
`
`The oscillation of the flowtubes is controlled by the control and measurement system,
`which outputs a drive signal to the driver. The drive signal is an amount of energy sent to the
`driver. The driver translates that energy into a corresponding amount of force or strength that is
`applied to move the flowtubes. In simple terms, the drive signal tells the driver how to move the
`flowtubes to keep them oscillating.
`
`
`When the flowtubes are oscillating in an empty state—without any material flowing
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`through them, they oscillate back and forth in sync with the drive signal.
`
`
`The driver generally oscillates the flowtubes by applying a drive signal in the shape of a
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`sine wave. As the flowtubes move or oscillate, the sensors on each side of the flowtubes generate
`signals that correspond to that movement. This can be easily seen from this bottom view of the
`oscillating flowtubes. Each sensor is continuously generating values related to the movement of
`the flowtube at the sensor location. Because there is no flow through the tubes in this example,
`the sensor signals are both in sync with the drive signal and in sync with each other.
`
`
`When fluid starts flowing through the pipe and into the flowtubes, the Coriolis effect is
`
`introduced.
`
`
`
`An in-depth understanding of the detailed physics of the Coriolis effect is are not
`necessary important for purposes of claim construction in this case. It is sufficient for this
`purpose to know that the Coriolis effect creates a force that deflects the two sides of each
`flowtube in opposite directions. This force creates a twisting of the flowtubes, which is shown
`here.
`
`
`
`When viewed from the bottom of the flowtubes, you can clearly see the twisting motion
`caused by the Coriolis effect. The Coriolis effect, and therefore, the amount of twist, becomes
`greater and greater with more and more fluid being pushed through the flowtubes.
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`
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`The twisting of the flowtube alters the sine waves coming out of each sensor. That is, the
`
`sine waves being recorded at each sensor are no longer in sync with the drive signal, but more
`importantly, they are no longer in sync with each other. As you can see when we superimpose
`the two signals, the signal from sensor 1 is slightly out of phase with the signal from sensor 2.
`We call this phenomenon a “time shift” or “phase shift”. The phase shift caused by the Coriolis
`effect is what allows the flowmeter to determine the mass flow rate of the material flowing
`through the flowtubes.
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`
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`This is because the amount of shift is directly proportional to the mass flow rate of
`material flowing through the flowtubes.
`
`
`
`Because this phase shift can only occur when the flowtubes are oscillating in a controlled
`manner and with a sufficient strength, it is critical that the flowmeter maintain oscillation of the
`flowtubes even under difficult conditions or when disturbances are introduced into the flowtubes.
`
`
`The task of maintaining oscillation in the face of a disturbance has been the biggest
`
`challenge to the success and utility of Coriolis flowmeters as a precise measurement tool over the
`years. And the number one disturbance for a Coriolis flowmeter is the presence of two phase
`flow in the flowtubes. Two phase flow is exactly as it sounds. It is when two different phases
`(liquid and gas) are present in the flowtube. Two-phase flow comes in many shapes and sizes as
`shown in the top image here. And it goes by various names depending upon which phases are
`present and in what percentages: some examples are aeration, entrained gas, high gas void
`fraction, slug flow, stratified flow, bubbles in the flow, etc.
`
`
`
`The bottom image shows what two-phase flow typically looks like with and Coriolis
`flowmeter: essentially bubbles, often of different sizes. Two-phase flow disrupts the flowtubes
`because the presence of bubbles radically changes the mass of the entire system and the bubbles
`provide room for the liquid to slosh around instead of moving straight through the flowtubes. To
`maintain oscillation in the presence of two phase flow, the strength or energy needed may
`increase by a factor of 100 or more, providing a major challenge to traditional Coriolis meter
`designs.
`
`
`
`Many industrial processes are not closed systems where all of the air can be eliminated.
`Instead, many systems have some point of exposure to the atmosphere, for example where raw
`materials are added or batched through the pipes. As shown here, air can be introduced into the
`system every time new material is added. Also, many systems have mixing elements that can
`create pockets of air or bubbles in the material. Batching is also a common practice in the
`industry. Batching involves repeatedly passing one batch of material through the system,
`emptying the system, and then passing another batch through the system. Obviously, the leading
`and trailing edges of material present two phase interfaces moving through the flowmeter. As
`shown, the empty or all gas transitions between batches form disturbances that can cause the
`flowmeter to shut down or quit oscillating. Traditional analog Coriolis flowmeters are not able to
`maintain oscillation of the flowtubes when these disturbances are introduced into the system.
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`
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`Jim Reizner, who was in charge of process and instrumentation worldwide for Procter
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`and Gamble, described the problem of two phase flow as the industry’s “dirty little secret.”
`Micro Motion published industry papers lamenting the fact that “coriolis flowmeters cannot
`handle two phase flow.”
`
`
`
`We have been discussing Coriolis flowmeters in general, now we must look more
`specifically at the control and measurement system in order to understand why two phase flow
`causes such serious problems, we must appreciate in more detail how the control and
`measurement system for Coriolis flowmeters generally works to maintain oscillation.
`
`
`A major advance in the Invensys’ patented technology is the ability to generate a drive
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`signal using digital signal processing. The method of generating the drive signal is of critical
`importance because, as we have discussed, without a stable oscillation, it is very difficult, if not
`impossible, to make accurate measurements. Simply put, the drive signal must be able to start the
`flowtubes oscillating and keep them oscillating at consistent amplitudes so that reliable
`measurements can be made.
`
`
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`Thus, this part of our discussion will focus almost entirely on the “drive side” of the
`control and measurement system because that is where the problems are introduced and that is
`where the solution of the inventions at issue reside.
`
`
`
`First, one must appreciate the fundamental difference between analog signals and digital
`signals. As shown here, analog signals are smooth, continuous curves, but contain no numerical
`data. Thus analog signals exist as real, physical phenomena such as current or voltage levels in a
`wire. Simple processing of analog signals is possible using basic electronics, with the major
`advantage that such processing is instantaneous. This means that there is little or no time delay
`between the signals sensed at the flowtubes and the signal sent to the driver. However, the real
`time nature of the analog domain comes with the major drawback that analog electronics are
`limited in terms of the range and accuracy of processing that can be performed.
`
`
`
`Transforming an analog signal into its digital equivalent in the “digital domain” as a
`sequence of numerical values is highly advantageous, because much more complex and accurate
`calculations can be performed on the data using digital signal processing. With advantages come
`disadvantages, and one major disadvantage of digital processing is the time delay associated with
`transforming the analog signals to the digital domain, performing all the calculations, and finally
`converting the desired drive signal back into an analog voltage or current for transmission to the
`flowtube.
`
`
`
`As we will see later on, this time delay is very significant in a Coriolis flowmeter. With
`the differences between analog and digital signals in mind, we can more clearly articulate the
`differences between traditional, analog drive Coriolis flowmeters and the patented digital drive
`Coriolis flowmeters.
`
`
`
`Let’s first look at the general arrangement of a traditional analog Coriolis flowmeter. In
`this figure, analog signals are indicated by solid lines, and digital signals are indicated by dotted
`lines. This flowmeter has a pair of sensors that each output a signal. The sensor signals are split
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`off into two directions. In the first direction, the analog sensor signals are fed through other
`analog components to become the analog drive signal, which is sent back into the driver. We will
`call this flow the “control” or “drive” side of the control and measurement system. In the second
`direction, the sensor signals are fed through an Analog-to-Digital Converter module, or ADC, to
`create a digital signal, shown here in orange. The control and measurement system uses this
`signal to calculate a measurement signal, shown here in blue. Ultimately, this is where the mass
`flow rate and perhaps other properties, such as density, are calculated. We will call this loop the
`“measurement” side of the control and measurement system.
`
`
`
`At this point it needs to be noted that while traditional prior art Coriolis flowmeters were
`referred to as analog, that reference is only to the analog drive signal. Digital components could
`be and were used on the measurement side in analog Coriolis flowmeters.
`
`
`
`Another point worth noting at this stage is that because the drive side is responsible for
`communicating with the driver to tell it how to keep the system moving, the drive side must be
`operating in a continuous process. In contrast, measurements need not be taken continuously and
`thus the operations on the measurement side can be intermittent. This is an important distinction
`because while the measurements might appear to us to be continuous because the sampling time
`is very fast, to the processing equipment it is not. Moreover, to the processing equipment there is
`a significant difference between the continuous need for a driver signal and the occasional need
`to take a measurement.
`
`
`
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`The ‘136 Patent describes a prior art Coriolis flowmeter in Figure 4.
`
`
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`As shown here, the signal that is provided to the drivers is not routed through the
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`processor or any other digital components. Thus, the drive side in the prior art Coriolis
`flowmeter is completely analog. Conversely, the mass flow calculation on the measurement side,
`does contain digital components such as the processor.
`
`
`So why is it that prior art analog Coriolis flowmeters cannot adequately maintain
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`oscillation when faced with a disturbance like two phase flow? The answer lies in the physical
`limitations associated with analog circuitry on the drive side. Let’s take a closer look at just the
`“drive side” of the analog control and measurement circuitry. As shown here and previously
`explained, the sensors are sending continuous analog signals to the control or drive side of the
`control and measurement system. These signals reflect the oscillation of the flowtubes.
`
`
`
`In a vacuum, once the flowtubes receive the drive signal, they oscillate at a desired
`amplitude and would stay at that amplitude continuously without the need for any modification
`or enhancement. The control system would simply feed the sensor signal back to the driver as the
`drive signal without any modification or enhancement. If no energy is being lost by the
`flowtubes, the flowtubes would continue to oscillate at the same amplitude and the sensor signals
`would continue to show, for example, an amplitude value of 1.
`
`
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`In reality, however, even in a system without two phase flow, there is always loss of
`energy in the system. Just as with the tuning fork, over time the system will stop oscillating. So,
`if the control and measurement system does nothing to the sensor signals and simply feeds them
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`back to the driver, the amplitude will slowly decrease and oscillation will get too low to be useful
`and may eventually stop oscillating.
`
`
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`In order to avoid this situation, the drive side circuitry applies what is known as a “drive
`gain” to the analog signal. The drive gain is merely a multiplier that is applied to the signal to
`increase its amplitude. As shown in this example, the flowtubes originally were oscillating at an
`amplitude of 1. However, due to normal energy loss, the oscillation amplitude begins to
`decrease. Here we see that it has fallen to 0.9 in this example. But if we apply a drive gain of 1.1
`to raise the energy or amplitude of the signal, then the driver has enough energy to maintain
`oscillation of the flowtubes at 1.
`
`
`
`Another way to think of this concept is by imagining pushing a child on a swing. Once
`the child is swinging at a desired height, if you push at just the right spot at the peak of the swing
`then it takes very little energy to keep the child swinging at the same height. The same is true
`with the flowtubes. Only a small amount of drive gain is needed to maintain oscillation as long
`as the flowtubes are already oscillating near the desired amplitude.
`
`
`Now let’s create a disturbance and introduce two phase flow into the analog flowmeter.
`
`Immediately the amplitude or energy of the oscillation decreases drastically. Energy is being lost
`due to the air in the system. This loss of energy is commonly referred to as a type of damping.
`
`
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`This concept can be illustrated by a basketball. If you fill a basketball full of air, it will
`bounce at a particular height or amplitude. If you fill the same basketball full of water, it will
`also bounce, although at a different height or amplitude. But if you fill the same basketball half
`full of air and half full of water, it will not bounce because the energy needed to bounce the ball
`is lost in the sloshing of the of the two phases in the ball at impact. A mixture of liquid and air in
`the flowtubes has a similar effect on the energy needed to oscillate the flowtubes.
`
`
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`In order to overcome this drastic loss of energy, the system needs to put in a massive
`amount of energy. For example, the drive gain needed to overcome two phase flow can be as
`much as 300 times the original drive gain in order to maintain oscillation. This is where
`traditional analog flowmeters fail. The limitations of the analog drive circuitry in the analog
`system make it incapable of introducing enough drive gain to overcome this loss. Moreover, in
`most cases, the maximum drive gain in the analog drive circuitry is less than the maximum
`capacity of the driver. This problem is exacerbated when the analog drive gain is already at its
`maximum. As the flowtubes continue to lose energy and thus the sensor signals continue to
`decrease, the drive signal will also fall because the drive gain will essentially become a constant
`multiplied by an ever decreasing sensor signal. In this example, even if the analog drive gain was
`as high as 50, it would continue to lose energy when faced with two phase flow. Thus, the
`system will continue to lose energy.
`
`
`
`A second somewhat related problem for prior art analog flowmeters relates to their
`inability to quickly and efficiently startup the oscillation of the flowtubes. It takes a lot of energy
`to get the initial oscillation going and analog flowmeters can take a relatively long time to start
`oscillation due to the maximum limits of energy they can apply.
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`
`
`That brings us to the inventions described in the Invensys Patents – digital drive Coriolis
`
`flowmeters. let’s look at the general arrangement of a digital drive Coriolis flowmeter. Recall
`that in the prior art analog flowmeter the drive side was completely analog, but the measurement
`side could contain some digital components. In a digital drive Coriolis flowmeter, the drive side
`flow is now processed in the digital domain as well.
`
`
`
`Again, solid lines represent analog signals, and dotted lines represent digital signals. Here
`the drive signal is generated by a processor in the control and measurement system—see the
`green, dotted line coming from the processor. As you can see, in the digital drive Coriolis
`flowmeter, the generation of the drive signal is controlled by a sophisticated control and
`measurement system as opposed to being controlled by simple, analog components.
`
`
`
`
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`Eventually, the digital drive signal is converted back to an analog by signal a Digital-to-
`Analog Converter module, or DAC. This is necessary because the drivers are simple mechanical
`devices that are controlled by analog signals.
`
`
`The ’136 Patent illustrates an example of a digital drive Coriolis flowmeter in Figure 5.
`
`
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`As shown here, the sensor signals—from each sensor, S—are digitized through Analog-
`
`to-Digital Converter modules (depicted as A/Ds) and routed through the processor before being
`sent back to each driver D via Digital-to-Analog Converter modules (depicted as D/As).
`
`
`
`As we’ll see next, this creates a great amount of versatility in how the flowtube is
`oscillated, which leads to many of the advancements claimed in the patents.
`
`
`But first, let’s look to see how converting the drive signal processing to the digital
`
`domain helps overcome the two phase flow problem of the prior art analog flowmeters.
`
`
`
`In this diagram we are looking again only at the drive side flow, which is where the
`Invensys Patents are focused. The sensor signals are converted from analog to digital signals
`using the Analog to Digital converters shown here as the ADC boxes. The drive signals then
`remain in the digital domain until they are converted back to analog using the Digital to Analog
`Converter shown as the DAC box. The benefit of converting to digital is that now we can apply
`an infinite amount of gain, limited only by the driver capacity. A digital control and
`measurement system is not limited by the physical limitations of the analog drive circuitry. This
`is because in the digital domain, the drive signal is now just a set of numbers that can be
`multiplied by any other number out to infinity. The only limit is what the driver can handle; the
`drive gain can continue to increase as much as it needs to, up to the maximum capacity of the
`driver. Thus, when two phase flow is encountered in a digital drive Coriolis flowmeter, the
`digital drive gain can apply a sufficient amount of energy to maintain oscillation of the
`flowtubes. And by maintaining oscillation of the flowtubes, the system can continue to take
`measurements, even during two phase flow.
`
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`This is what is most significant about the digital drive Coriolis flowmeter. Unlike in the
`
`prior art systems, the disturbance does not interfere with the ability of the system to reliably
`measure the mass of the flow.
`
`
`The digital drive Coriolis flowmeters claimed in the Invensys Patents have other related
`
`advantages and functionality as well. The most prominent is the ability to have different drive
`modes. For present purposes, we will limit the discussion to two possible modes: a feedback
`mode, in which the drive side sensor signal is the basis for the drive signal; and a synthesis
`mode, such as during startup or when the flowmeter is running at peak operation. During
`synthesis mode, the drive side still may monitor and/or consider the sensor signal information,
`but the drive signal is purely a synthesized or created signal and not necessarily based on the
`sensor signal. In the next few slides, we will demonstrate these two basic drive signal modes
`taught in the Invensys Patents by walking through a typical sequence of events encountered by a
`digital drive Coriolis flowmeter.
`
`
`The first thing a digital drive Coriolis flowmeter has to do is startup—that is to work to
`
`get the flowtubes moving or oscillating when they are not. This startup process is carried out in
`synthesis mode. This is because when starting up the flowmeter system does not know what
`energy is needed to initiate oscillation. So, the drive side sends a pseudo random amount of
`energy in the form of various frequencies and amplitudes to the driver hoping to hit the
`frequency and amplitude that will get the flowtubes moving with whatever material happens to
`be flowing in them.
`
`
`
`Once the flowtubes begin to oscillate, the drive mode will move into a positive feedback
`mode. At this initial stage in this example, positive feedback involves ramping up the drive gain
`(or energy multiplier) that is applied to the drive until the flowtube begins to oscillate at a desired
`amplitude and frequency. Once a sufficient amplitude of oscillation is reached, as determined by
`the control and measurement system, the positive feedback mode can adjust the drive signal to
`keep it steady or the control and measurement system can move back into a synthesis mode.
`
`
`
`In this type of operation in synthesis mode, which can be referred to as pure synthesis, the
`control and measurement system generates a pure sine wave at the exact amplitude and
`frequency that the control and measurement system decides is optimum. The system can operate
`in pure synthesis mode until something affects the oscillation or amplitude of the flowtubes, such
`that the system decides to switch modes.
`
`
`
`In this example, damping or energy loss has actually decreased in the system—which can
`happen for a variety of reasons, including moving from two phase flow back to pure liquid flow
`When damping decreases, the system operates more efficiently, which in turn causes the
`amplitude to increase. Here, a sensor signal has been overlaid in red to indicate how the positive
`feedback system will respond. As you can see, the amplitude in the flowtubes has increased even
`though the drive signal has not. Thus the control and measurement system will want to try and
`decrease the amplitude in the flowtubes back to the desired level. To do this, the control and
`measurement system can ramp down the amplitude of the drive signal, which will cause the
`sensor signal to ramp down as the natural damping of the system retards the oscillation of the
`flowtubes.
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`
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`In some instances, ramping down the drive signal and waiting for the natural damping to
`occur is not enough. In such instances, analog flowmeters failed. The digital drive Coriolis
`flowmeter, on the other hand, can use negative gain.
`
`
`
`Negative gain is when the drive signal is 180 degrees out of phase with the sensor
`signals. That is, the drive signal is the negative of the sensor signal. This causes the drive signal
`to oppose the oscillation of the flow tubes and ultimately bring down the amplitude of the
`flowtubes until a desired amplitude is achieved.
`
`
`Positive and negative gain can be understood by thinking again about pushing a child on
`
`a swing. One can increase the height of the swinging arc (the amplitude) by pushing in the
`direction the child is moving. Conversely, one can decrease the height of the swing by pushing
`with less force and waiting for the height of the swing to decrease. Another method of slowing
`down the child is to actively push in the opposite direction. This requires altering the pattern of
`pushing in a significant way, which only the digital drive version of a flowmeter can accomplish.
`
`
`All these different modes are important because they allow the flowmeter to apply the
`
`appropriate drive signal in response to the conditions encountered in the flowtubes.
`
`
`
`This concludes the first portion of the tutorial on the technology related to the Invensys
`Patents.
`
`
`
`EAST\72694140
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