Instrumentation display system and related calibration method

Abstract

An instrumentation display system comprises a visual display and a sensor interface operatively connectable to at least one resistance-based sensor. The sensor interface determines an electrical resistance value of the sensor corresponding to a measured value of a physical state or condition of machinery or an environment measured by the sensor. A controller is configured to control a user interface, presented on the visual display, which enables a user to input a plurality of paired calibration values for the system. Each paired calibration value comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition corresponding to the predetermined resistance. The controller receives the electrical resistance value from the sensor interface and derives the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values, wherein the measured value is displayed on the user interface.

Description

INSTRUMENTATION DISPLAY SYSTEM AND RELATED CALIBRATION METHODField

[0001] The present invention relates to instrumentation and condition monitoring. More particularly, the invention relates to an instrumentation display system for monitoring the physical state or condition of machinery and operating environments using resistancebased sensors.Background

[0002] Instrumentation systems are used to monitor the operating state and condition of vehicles and their working parts. Motorboats, for example, often have a set of sensors that are operatively connected to gauges in the boat’s cockpit for displaying engine temperature, oil pressure, fuel level and other measurable boat operating parameters. Industrial plant and machinery also use sensors and gauges for monitoring operating and environmental conditions.

[0003] A resistance-based sensor is a common type of sensor device used in analogue instrumentation systems. The sensor receives an electrical current via a wire from a control circuit and offers a resistance to the current. The magnitude of the resistance varies in proportion to changes in the relevant physical parameter that the sensor measures. For example, a resistance-based temperature sensor exhibits a resistance value that varies in a continuous (analogue) manner in proportion to its temperature. An electromechanical gauge can be operatively connected to the sensor that responds to the resistance to visually indicate the temperature. An individual gauge is provided for each type of sensor installed in the relevant vehicle or machinery. A set of the gauges are typically arranged together on a console, cockpit or dashboard of the vehicle or machinery.

[0004] Resistance-based sensors are robust and reliable devices that have been used in vehicles and machines for decades. A second-hand boat will often have a large number of these sensors installed in multiple different places throughout the engine and on various other equipment on the boat. For modern vehicles, manufacturers are progressively moving away from the use of resistance sensors and analogue instrumentation. The modern approach is to use sophisticated sensor arrays that output digital signals that aretransmitted to electronic visual displays via a CAN bus network. The sensor readings are displayed using digital gauges that are rendered on the screen of the display.

[0005] The owner of an older vehicle that is equipped with resistance-based sensors may want to retrofit a modern digital display into their vehicle to replace the vehicle’s analogue gauges. For example, the gauges may have succumbed to wear and tear and may no longer be accurate or operational. Visual displays that receive digital sensor signals are not directly connectable to the sensors as the sensors are designed to operate with electro-mechanical gauges only. Typically, with older engines and equipment, the boat owner must remove the legacy sensors and replace them with modern sensors that are compatible with a modern digital display if that type of display is wanted or required. Removing the legacy sensors, and installing and connecting the modern sensors to the digital display, are laboursome and expensive tasks to perform.

[0006] The preceding discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the present application.Summary

[0007] According to the present invention, there is provided an instrumentation display system, comprising: a visual display; a sensor interface connectable to at least one resistance-based sensor, wherein the sensor interface is configured to determine an electrical resistance value of the sensor, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of machinery or an environment measured by the sensor; and a controller configured to control a user interface presented on the visual display, wherein the user interface enables a user of the system to input a plurality of paired calibration values for the system, wherein each of the paired calibration values comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance, wherein the controller receives the electrical resistance value from the sensor interface and is configured to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values, andwherein the controller causes the measured value to be displayed or indicated to the user on the user interface.

[0008] The controller may be configured to determine one or more equations of one or more geometric lines respectively, wherein the geometric lines intersect with, or approximate, the paired calibration values when the paired calibration values are plotted on a pair of axes, and to use the equations to interpolate the measured value.

[0009] The geometric lines may comprise a plurality of straight line segments, wherein each of the straight line segments extends between an adjacent pair of the paired calibration values. In other examples, the geometric lines may comprise a curved line intersecting, or approximating, the paired calibration values.

[0010] The user interface may enable the user to input at least six of the paired calibration values.

[0011] The controller may cause the measured value to be indicated by a gauge and / or numerically displayed on the user interface.

[0012] The gauge may be rendered graphically on a screen of the visual display.

[0013] The sensor interface may comprise an analogue-to-digital converter for determining the electrical resistance value of the sensor and sending the electrical resistance value as a digital signal to the controller.

[0014] The electronic visual display may be a touch screen display.

[0015] The measured value may be a temperature, pressure, or fluid level or flow rate relating to a part or substance used by or in the machinery or environment.

[0016] The electrical resistance value of the sensor may be displayed on the user interface.

[0017] The user interface may enable the user to input a plurality of calibration datasets for the visual display, wherein each calibration dataset comprises a plurality of paired calibration values for one of a plurality of resistance-based sensors connectable to the sensor interface.

[0018] The present invention also provides a visual display, comprising: a sensor interface connectable to at least one resistance-based sensor, wherein the sensor interface is configured to determine an electrical resistance value of the sensor, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of machinery or an environment measured by the sensor; and a controller configured to control a user interface presented on a screen of the visual display, wherein the user interface enables a user of the visual display to input a plurality of paired calibration values for the visual display, wherein each of the paired calibration values comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance, wherein the controller receives the electrical resistance value from the sensor interface and is configured to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values, and wherein the controller causes the measured value to be displayed or indicated to the user on the user interface.

[0019] The present invention also provides a method of displaying sensor information on a visual display, wherein the method comprises: obtaining, by a sensor interface of the visual display, an electrical resistance value of at least one resistance-based sensor operatively connected to the visual display, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of machinery or an environment measured by the sensor; obtaining, by a user interface presented on the visual display, a plurality of paired calibration values for the visual display, wherein each of the paired calibration values is input by a user of the visual display and comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance; providing the electrical resistance value to a controller of the visual display;using the controller to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values; and displaying or indicating the measured value to the user of the visual display on the user interface.

[0020] The method may comprise using the controller to determine one or more equations of one or more geometric lines respectively, wherein the geometric lines intersect with, or approximate, the paired calibration values when the paired calibration values are plotted on a pair of axes, and to use the equations to interpolate the measured value. In such examples, the geometric lines may comprise a plurality of straight line segments, wherein each of the straight line segments extends between an adjacent pair of the paired calibration values.

[0021] The present invention also provides a method of calibrating an instrumentation display system for a resistance-based sensor, wherein the method comprises: connecting a sensor interface of the system to the resistance-based sensor, wherein the sensor interface is configured to determine an electrical resistance value of the sensor, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of machinery or an environment measured by the sensor; obtaining, by a user interface presented on a visual display of the system, a plurality of paired calibration values for the system, wherein each of the paired calibration values is input by a user of the system and comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance; and configuring a controller of the system to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values, such that the controller can cause the measured value to be displayed or indicated to the user of the system on the user interface when the controller receives the electrical resistance value from the sensor interface.

[0022] The predetermined value of at least one of the paired calibration values may correspond to a critical value of the physical state or condition.

[0023] The critical value may be a critical temperature, pressure, or fluid level or flow rate relating to a part or substance used by or in the machinery or environment.

[0024] The present invention also provides a method of retrofitting an instrumentation display system into a vehicle or machine, wherein the vehicle or machine comprises at least one analogue gauge, wherein the analogue gauge is operatively connected to a resistance-based sensor deployed in the vehicle or machine, the method comprising: disconnecting the analogue gauge from the sensor and removing the analogue gauge from the vehicle or machine; installing a visual display and a sensor interface of the system into the vehicle or machine; connecting the sensor interface to the sensor, wherein the sensor interface is configured to determine an electrical resistance value of the sensor, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of the vehicle or machine or of an environment measured by the sensor; inputting into the system, by a user interface presented on the visual display, a plurality of paired calibration values for the system, wherein each of the paired calibration values comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance; and configuring a controller of the system to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values, such that the controller can cause the measured value to be displayed or indicated to the user of the system on the user interface when the controller receives the electrical resistance value from the sensor interface.Brief Description of Drawings

[0025] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:FIG. 1 is a schematic diagram of an instrumentation display system according to an example embodiment of the invention;FIG. 2 is a representation of a calibration screen of a user interface displayed on a visual display of the system;FIG. 3 is an instrumentation screen of the user interface displayed on the visual display;FIG. 4 is a graph with a curve on its axes illustrating a nonlinear relationship between resistance and temperature for a resistance-based temperature sensor operatively connected to the visual display;FIG. 5 is a graph with a curve on its axes illustrating a linear relationship between resistance and temperature for a resistance-based temperature sensor in a further example embodiment of the invention;FIG. 6 is a graph with a plurality of paired calibration values plotted on the graph’s axes for the resistance-based temperature sensor of FIG. 4;FIG. 7 is a graph with a plurality of paired calibration values plotted on the graph’s axes for a resistance-based temperature sensor in a further example embodiment of the invention; andFIG. 8 is an isometric view of a visual display of the instrumentation display system.Description of Embodiments

[0026] Referring to Figures 1 to 3, an example embodiment of the present invention provides an instrumentation display system 10. The system 10 comprises a visual display 12 and a sensor interface 14 operatively connectable to at least one resistance-based sensor 16. The sensor interface 14 is configured to determine an electrical resistance value of the sensor 16, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of machinery 18 or an environment measured by the sensor 16.

[0027] A controller 20 of the system 10 is configured to control a user interface 22 presented on the visual display 12. As depicted in FIG. 2, the user interface 22 enables a user of the system 10 to input a plurality of paired calibration values 24 for the system 10, wherein each of the paired calibration values 24 comprises a predetermined resistance 26 of the sensor 16 and a predetermined value 28 of the physical state or condition that corresponds to the predetermined resistance 26. The controller 20 is configured to receive the electrical resistance value from the sensor interface 14 and to derive the measured value from the electrical resistance value by interpolating or extrapolating the measuredvalue from the paired calibration values 24. The controller 20 causes the measured value to be displayed or indicated to the user on the user interface 22, as depicted in FIG. 3.

[0028] More particularly, in the example depicted the system 10 is used to monitor the operating condition of a vehicle's engine 18. A total of three sensors 16, 30, 31 are operatively connected to the sensor interface 14 of the system 10 for monitoring three separate operating parameters of the engine 18 respectively. The first sensor 16 is a resistance-based temperature sensor deployed in the engine 18 for monitoring the temperature of the engine’s coolant. The first sensor 16 exhibits an electrical resistance that decreases as the measured temperature increases, and vice versa. The second sensor 30 is a resistance-based pressure sensor deployed in the engine 18 for monitoring the pressure of the engine’s oil. The third sensor 31 is a resistance-based fluid level sensor for monitoring the level of fuel in a tank 29 that supplies fuel to the engine 18.

[0029] Each of the sensors 16, 30, 31 is operatively connected to the sensor interface 14 by a single wire and uses a ground / battery negative or earth return to complete the circuit to the display 22. The sensor interface 14 comprises circuitry that operates to supply a regulated electrical current along each of the wires to each of the sensor circuits. Each sensor may have a metallic casing that, via the grounded engine block and fuel tank (or via a separate ground wire shared by the display 12), provides a shared ground connection to a battery 40 that supplies power to the visual display 12. For each sensor 16, 30, 31 , the interface 14 and controller 20 measure the voltage and current of the electrical signal that is returned from the sensor and calculates the sensor’s corresponding resistance by Ohm's law.

[0030] The sensor interface 14 comprises three analogue-to-digital converters (ADCs) for converting the sensor resistances into corresponding digital signals that are supplied to the controller 20. The sensor interface 14 may comprise an integrated circuit (chip) that performs the ADC functionality for all connected sensors 16, 30, 31. While single-wire sensors are used in the example depicted, each sensor may comprise a two-wire sensor that has a first wire extending to the sensor interface 14 and a second wire that is grounded to the engine / battery.

[0031] The visual display 12 is a touch-sensitive screen, such as a capacitance TFT LCD screen, that is controlled by the controller 20. A graphical user interface (GUI) 22 is digitally rendered on the screen which enables the user to interact with the system 10. The GUI22 comprises multiple different screens that can be displayed on the screen on demand. For example, FIG. 2 shows a calibration screen 32 of the GUI 22 that enables the user to enter a total of six paired calibration values 24 for the sensor 16.

[0032] FIG. 3 shows an instrumentation screen 34 of the GUI 22. The screen 34 shows a temperature gauge 36 for indicating the temperature of the coolant in the engine 18 to the user, and a pressure gauge 38 for indicating the oil pressure of the engine 18. Both gauges 36, 38 are digitally rendered on the screen 34 and generally resemble analogue-style gauges. The GUI 22 will enable the user to view another instrumentation screen (not shown) which displays a gauge showing the liquid level in the fuel tank 29. The set of instrumentation screens allow the various variable states and operating parameters of the engine 18, as measured by the sensors 16, 30, 31 , to be displayed to the user in a meaningful and clear way. The GUI 22 allows the user to switch between the various screens, as required, using an appropriate interface control. For example, the GUI 22 may provide “swipe” gesture functionality that allows the user to switch between the various instrumentation screens by placing a finger on the display 12 and swiping in a particular direction. The GUI 22 may also provide “push and hold” gesture functionality that allows the user to switch between the various instrumentation and calibration screens by placing a finger on any one gauge on the display 12 and holding their finger in place while a change of screen occurs.

[0033] Referring to FIG. 2, the calibration screen 32 presents the user with a set of boxes that are arranged into two adjacent columns. The boxes in the left hand column enable the user to enter six different predetermined resistance values 26 for the relevant sensor 16. The boxes in the right hand column enable the user to enter six different predetermined temperature values 28 that correspond to the respective resistance values 26. Each pair of adjacent boxes in the columns represents a pair of calibration values 24 for the sensor 16. For example, in the uppermost pair of boxes depicted in FIG. 2, a user of the system has entered a resistance value 26 of six hundred (600) ohms (Q) and a corresponding temperature value 28 of zero (0) degrees centigrade (°C). This pair of calibration values lets the system 10 know that the resistance of the sensor 16 will be 600 Q when the sensor 16 measures an engine coolant temperature of 0°C. The GUI 22 provides an appropriate interface control to enable the user to enter each of the values into the boxes. For example, the GUI 22 may provide a touch sensitive keyboard that appears on the screen 32 when the user clicks on each box.

[0034] The user will typically obtain the values that need to be entered into the boxes on the calibration screen 32 from the relevant manufacturer or vendor of the sensor 16. Alternatively, the GUI 22 also displays the resistance 42 of the sensor 16 that is currently determined by the sensor interface 14 in real-time. The user may use this information to determine the values that need to be entered into the boxes in certain applications. For example, if the engine 18 is running at a particular known temperature, as measured by a separate temperature measuring device located on the engine block, then the user can read the corresponding resistance value 42 and enter a resistance- temperature pair 24 into the relevant box. Whilst each sensor 16, 30, 31 will have a manufacturer's specification for its resistance, in practice the resistance may be affected by various factors such as the particular wiring and sensor connections that are used, and the sensor’s working condition. The displayed resistance 42, therefore, assists the user to perform accurate sensor calibration in cases where the sensor resistance deviates from its labelled specification.

[0035] As illustrated by the graph 44 in FIG. 4, the resistance of the temperature sensor 16 (ref. y axis of the graph) decays in a nonlinear manner as the engine coolant temperature measured by the sensor 16 (ref. x axis of the graph) increases. Accordingly, the calibration values 24 that are entered into the boxes on the screen 32 reflect this nonlinear relationship. In examples where a different type of sensor is being calibrated, the relationship between (a) the sensor’s resistance and (b) the value of the relevant physical state of condition measured by the sensor, may be different to the relationship illustrated in FIG. 4. The sensor may exhibit a linear, exponential or logarithmic relationship or a complex algebraic relationship that involves dependencies on multiple physical factors. FIG. 5 provides a graph 46 for an example whereby a temperature sensor is used that exhibits a linear relationship between the sensor resistance and temperature measured by the sensor, which provides a high level of measurement accuracy.

[0036] Essentially, the set of calibration values 24 represent a discrete sample of a range of continuous resistance and measurement values applying to the sensor 16. In the example depicted, the screen 32 enables the user to enter a total of six paired calibration values 24. Six pairs are sufficient to enable the controller 20 to derive a measured value from the sensor resistance readings with a good degree of accuracy in a wide range of practical applications. It will be appreciated, however, that the system 10 may allow the user to enter a different number of the calibration values 24. For example, the system 10may allow the user to enter more than six calibration values to increase the accuracy of the derivation process performed by the controller 20.

[0037] In use, the electrical resistance value of the sensor 16 is measured or determined by the sensor interface 14 and is supplied to the controller 20. The controller 20 derives the temperature value that is represented by the measured resistance value by interpolating the temperature value from the six paired calibration values 24. The controller 20 may use a variety of different methods for performing this interpolation process. For example, a linear interpolation / regression technique may be used. More particularly, FIG. 6 illustrates a graph 47 wherein six paired calibration values 24 are plotted as six respective points 48 on the axes of the graph 47. The x axis of the graph 47 represents the temperature of each point 48, in °C, and the y axis of the graph 47 represents the resistance of each point 48, in Q. The controller 20 may use the six points 48 to determine the equations of five straight line segments 50 that extend through the points 48. Each line segment 50 extends between an adjacent pair of the points 48. For example, the line segment that is labelled 52 in FIG. 6 extends between an adjacent pair of points that are labelled 54 and 56 respectively.

[0038] Each equation will typically be in the form y = mx + c, wherein m is the gradient of the relevant line segment 50; c is the y axis intercept of the relevant line segment 50, when extrapolated through to the y axis; y is the relevant resistance value; and x is the relevant temperature value. The value of x falls (inclusively) within the range min - max, wherein min is the temperature value of the leftmost the two adjacent points 48 that the relevant line segment 50 extends between (e.g., point 54 for line segment 52), and wherein max is the temperature value of the rightmost of the two adjacent points 48 (e.g., point 56 for line segment 52).

[0039] Upon measuring the resistance of the sensor 16, y, the controller 20 can determine the line segment 50 that is closest to the resistance and then calculate the temperature, x, using the equation corresponding to the closest segment 50. In examples where the resistance, y, extends beyond the maximum range of resistances represented by the set of line segments 50, the controller 20 may calculate an estimate of the temperature, x, by using the equation of the closest segment 50 to extrapolate the temperature.

[0040] By executing these techniques, the controller 20 can essentially calculate an estimate of the temperature value that corresponds to the resistance value measured bythe sensor interface 14. It will be appreciated that the accuracy of the estimates will increase as the resistance value approaches one of the points 48. Optimal accuracy is achieved when the resistance value matches one of the points 48. Using six points 48 allows for a level of accuracy that is acceptable in many practical applications. This includes when measuring engine coolant temperature using a temperature sensor 16, as per the depicted example.

[0041] The system 10 may be used to perform condition monitoring of a system, vehicle or machine in which one or more critical operating parameters or environmental variables need to be carefully monitored. In such cases, the user may input the calibration values 24 into the system 10 so that they are aligned with any critical values. For example, the user of the system 10 that is depicted may want to ensure that the engine coolant temperature does not exceed a critical maximum temperature. The user may, therefore, input the critical maximum temperature into the lowermost pair of boxes shown in FIG. 2 to ensure that optimal accuracy is achieved when the engine coolant temperature reaches this maximum.

[0042] In the example depicted in FIG. 6, the controller 20 uses the set of equations determined for the set of straight line segments 50 to derive the temperature corresponding to each measured resistance of the sensor 16. In other examples, the controller 20 may determine one or more equations of other types of geometric lines that intersect (or approximate) the points 48 to interpolate or extrapolate the temperature. For example, the controller 20 may determine the equation of a curved line that intersects (or approximates) each of the points 48. The controller 20 may use a variety of different mathematical or algorithmic curve fitting techniques to determine the equation, including best fit and exact fit techniques, such as polynomial interpolation / regression. Essentially, the connection of the set of calibration points 48 forms either a linear or non-linear plotted geometric line which is unique to the particular sensor 16 being calibrated on the screen 32.

[0043] FIG. 7 illustrates another graph 58 where six paired calibration values 24 are plotted as six respective points 48 on the axes of the graph 58. In this example, the controller 20 has determined an equation of a single curved line 50 that extends through each of the points 48. For example, the curved line 50 may correspond to an exponential decay and the equation may be in the form y = abx+ c where a, b and c are constants (0< b < 1). Upon measuring the resistance of the sensor 16, y, the controller 20 calculates the corresponding temperature, x, using the single equation.

[0044] The user interface 22 will provide additional calibration screens (not shown) that are equivalent to the screen depicted in FIG. 2 to enable the user to input a set of paired calibration values for each of the oil pressure sensor 30 and fuel level sensor 31. The user may switch between the various calibration screens using a swipe or push-and-hold gesture or by using an appropriate Ul control provided via the user interface 22. The user interface 22 may also allow the user to input and set one or more alarms for the sensor data. For example, the user may configure the system 10 so that an audible and / or visual alarm is raised when any measured value, e.g., engine coolant temperature or oil pressure, exceeds or drops below a critical value.

[0045] As illustrated in FIG. 8, the visual display 12 may be an integrated device that comprises a touch-sensitive screen 60 mounted on the front side of a housing 62. The housing 62 contains the sensor interface 14 and controller 20. The housing 62 is pivotally connected to a cradle 64 that allows the display 12 to be pivoted about an axis. The cradle 64 can be mounted onto a surface on a cockpit or dashboard of a vehicle. The display 12 may be connectable to a master battery stored on the vehicle via a power cord that supplies power to the various internal electronic components of the display 12. The controller 20 may comprise a processor, a programmable logic controller (PLC), a programmable logic array (PLA) or similar electronic controller device, including multiple electronic controller devices operatively connected together via a network, bus, interconnect or a similar communication means.

[0046] Now that example embodiments of the instrumentation display system have been described, it will be apparent that it provides a number of advantages over the prior art, including the following:(i) The system allows digital instrumentation to be retrofitted into vehicles and machines that are equipped with resistance-based sensors and traditional analogue gauges in a cost effective and practical manner. To perform a retrofit, the analogue gauges are disconnected from the sensors and removed from the relevant vehicle of machine. The visual display of the system is then connected to the sensors and calibrated using the method disclosed herein. The system, therefore, provides a “plug and play” replacement to the traditional analogue gauges and only requires minimal wiring to install;(ii) The system provides a simple, flexible and user friendly sensor calibration interface and method. The user is not required to connect any external equipment to the display 12 to perform the sensor calibration method. The user may calibrate the system to work with a large number of sensors, and such that a single display can be used to monitor the condition of several items of equipment simultaneously;(iii) The system can be used to monitor the condition and operating state of a wide range of machinery, vehicles, plant and related operating environments. This includes cars, motorboats and manufacturing equipment.

[0047] In the example depicted, the system 10 is operatively connected to a resistancebased temperature sensor 16, pressure sensor 30 and fluid level sensor 31. The system 10 may, however, be operatively connected to other types of resistance-based sensors for various applications including in marine, automotive and industrial environments. Some non-limiting examples include sensors for measuring positional displacement, gas pressure, fluid flow rate and level, water quality and battery voltage.

[0048] For the purpose of this specification, the word “comprising” means “including but not limited to”, and the word "comprises" has a corresponding meaning. It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country.

[0049] The above embodiments have been described by way of example only and modifications are possible within the scope of the claims that follow.

Claims

Claims1. An instrumentation display system, comprising: a visual display; a sensor interface connectable to at least one resistance-based sensor, wherein the sensor interface is configured to determine an electrical resistance value of the sensor, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of machinery or an environment measured by the sensor; and a controller configured to control a user interface presented on the visual display, wherein the user interface enables a user of the system to input a plurality of paired calibration values for the system, wherein each of the paired calibration values comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance, wherein the controller receives the electrical resistance value from the sensor interface and is configured to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values, and wherein the controller causes the measured value to be displayed or indicated to the user on the user interface.

2. The instrumentation display system according to claim 1 , wherein the controller is configured to determine one or more equations of one or more geometric lines respectively, wherein the geometric lines intersect with, or approximate, the paired calibration values when the paired calibration values are plotted on a pair of axes, and to use the equations to interpolate the measured value.

3. The instrumentation display system according to claim 2, wherein the geometric lines comprise a plurality of straight line segments, wherein each of the straight line segments extends between an adjacent pair of the paired calibration values.

4. The instrumentation display system according to claim 2, wherein the geometric lines comprise a curved line intersecting, or approximating, the paired calibration values.

5. The instrumentation display system according to any one of the preceding claims, wherein the user interface enables the user to input at least six of the paired calibration values.

6. The instrumentation display system according to any one of the preceding claims, wherein the controller causes the measured value to be indicated by a gauge displayed on the user interface.

7. The instrumentation display system according to claim 6, wherein the gauge is rendered graphically on a screen of the visual display.

8. The instrumentation display system according to any one of the preceding claims, wherein the sensor interface comprises an analogue-to-digital converter for determining and supplying the electrical resistance value as a digital signal to the controller.

9. The instrumentation display system according to any one of the preceding claims, wherein the electronic visual display is a touch screen display.

10. The instrumentation display system according to any one of the preceding claims, wherein the measured value is a temperature or pressure of a part or substance used by or in the machinery or environment.

11. The instrumentation display system according to any one of the preceding claims, wherein the user interface enables the user to input a plurality of calibration datasets for the visual display, wherein each calibration dataset comprises a plurality of paired calibration values for one of a plurality of resistance-based sensors connectable to the sensor interface.

12. The instrumentation display system according to any one of the preceding claims, wherein the electrical resistance value is displayed on the user interface.

13. A visual display, comprising: a sensor interface connectable to at least one resistance-based sensor, wherein the sensor interface is configured to determine an electrical resistance value of the sensor, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of machinery or an environment measured by the sensor; anda controller configured to control a user interface presented on a screen of the visual display, wherein the user interface enables a user of the visual display to input a plurality of paired calibration values for the visual display, wherein each of the paired calibration values comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance, wherein the controller receives the electrical resistance value from the sensor interface and is configured to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values, and wherein the controller causes the measured value to be displayed or indicated to the user on the user interface.

14. A method of displaying sensor information on a visual display, the method comprising: obtaining, by a sensor interface of the visual display, an electrical resistance value of at least one resistance-based sensor operatively connected to the visual display, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of machinery or an environment measured by the sensor; obtaining, by a user interface presented on the visual display, a plurality of paired calibration values for the visual display, wherein each of the paired calibration values is input by a user of the visual display and comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance; providing the electrical resistance value to a controller of the visual display; using the controller to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values; and displaying or indicating the measured value to the user of the visual display on the user interface.

15. The method according to claim 14, wherein the method comprises using the controller to determine one or more equations of one or more geometric lines respectively, wherein the geometric lines intersect with, or approximate, the pairedcalibration values when the paired calibration values are plotted on a pair of axes, and to use the equations to interpolate the measured value.

16. The method according to claim 15, wherein the geometric lines comprise a plurality of straight line segments, wherein each of the straight line segments extends between an adjacent pair of the paired calibration values.

17. A method of calibrating an instrumentation display system for a resistance-based sensor, wherein the method comprises: connecting a sensor interface of the system to the resistance-based sensor, wherein the sensor interface is configured to determine an electrical resistance value of the sensor, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of machinery or an environment measured by the sensor; obtaining, by a user interface presented on a visual display of the system, a plurality of paired calibration values for the system, wherein each of the paired calibration values is input by a user of the system and comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance; and configuring a controller of the system to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values, such that the controller can cause the measured value to be displayed or indicated to the user of the system on the user interface when the controller receives the electrical resistance value from the sensor interface.

18. The method according to claim 17, wherein the predetermined value of at least one of the paired calibration values corresponds to a critical value of the physical state or condition.

19. The method according to claim 18, wherein the critical value is a critical temperature or pressure of a part or substance used by or in the machinery or environment.

20. A method of retrofitting an instrumentation display system into a vehicle or machine, wherein the vehicle or machine comprises at least one analogue gauge,wherein the analogue gauge is operatively connected to a resistance-based sensor deployed in the vehicle or machine, the method comprising: disconnecting the analogue gauge from the sensor and removing the analogue gauge from the vehicle or machine; installing a visual display and a sensor interface of the system into the vehicle or machine; connecting the sensor interface to the sensor, wherein the sensor interface is configured to determine an electrical resistance value of the sensor, wherein the electrical resistance value corresponds to a measured value of a physical state or condition of the vehicle or machine or of an environment measured by the sensor; inputting into the system, by a user interface presented on the visual display, a plurality of paired calibration values for the system, wherein each of the paired calibration values comprises a predetermined resistance of the sensor and a predetermined value of the physical state or condition that corresponds to the predetermined resistance; and configuring a controller of the system to derive the measured value from the electrical resistance value by interpolating or extrapolating the measured value from the paired calibration values, such that the controller can cause the measured value to be displayed or indicated to the user of the system on the user interface when the controller receives the electrical resistance value from the sensor interface.

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