Display device for linearly displaying a non-linear input variable

• US 5,751,611 A
• Filed: 10/03/1996
• Issued: 05/12/1998
• Est. Priority Date: 10/03/1996
• Status: Expired due to Term

• Current Assignee: Prime Technology Incorporated (General Dynamics Corporation)
• Original Assignee: Prime Technology Incorporated (General Dynamics Corporation)
• Inventors: Jamieson, Brian Thomas
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): Vo, Hien
• Application Number:
  US08/726,345
• Time in Patent Office: 586 Days
• Field of Search: 364/573, 364/571.04, 364/509, 364/550, 364/571.01, 364/571.02, 73/49.2, 73/1 H, 73/1 R, 73/304 R
• US Class Current: 345/35
• CPC Class Codes: G01D 3/022 having an ideal characteristic, map or correction data stored in a digital memory
• CPC Class Codes: G01F 23/802 Particular electronic circuits for digital processing equipment

Abstract

A display device, in form of a panel meter which includes a combination of a linear bar graph and digital numeric display, linearly displays a non-linear input variable at an infinite number of input points. A microprocessor receives a digital input, which can be a converted analog signal, representing a non-linear variable such as a liquid level height in a tank or reservoir or a corresponding analog input received through an analog to digital (A/D) converter. A non-volatile memory stores a finite set of predetermined number n of correlated input/output points (x_n, y_n ) which together define a conversion function for converting a given input (x_n) at any given point (x_n, y_n ) to an associated output (y_n). Each two adjacent points (x₀, y₀) and (x₁, y₁) define a straight line segment. The microprocessor is programmed to interpolate for any given input x between two points (x₀, x₁) to provide an output (y) between associated outputs (y₀, y₁) by making the following computation: ##EQU1##

Claims

1. A display device for linearly displaying a non-linear input variable at an infinite number of input points over a finite range, comprising input means for receiving data representative of a non-linear input variable;

computer means connected to said input means for receiving the data;

a substantially linear display having a display input connected to said computer means for providing an output indication which vary linearly with a signal applied to said display input;

non-volatile memory means connected to said computer means for storing a plurality of finite sets of predetermined points n of correlated input/output points (x_n, y_n) each defining a specific conversion function representative of an associated non-linear input variable for converting a given input (x_n) at any given point (x_n, y_n) to an associated output (y_n), each two adjacent points (x₀, y₀) and (x₁, y₁) defining a straight line segment, said computer means being programmed to interpolate for any given x between two inputs (x₀, x₁) to provide an output (y) between associated outputs (y₀, y₁) by making the following computation;

##EQU5## and personality means for selecting one of said plurality of sets of points for a given application which linearizes a predetermined specific non-linear input variable.

2. A display device as defined in claim 1, wherein the data is initially generated in analog form, and further comprising signal conditioning means for converting the analog data into digital data.

3. A display device as defined in claim 1, wherein said display comprises an analog meter.

4. A display device as defined in claim 1, wherein said display comprises a LED bar graph.

5. A display device as defined in claim 1, wherein said display comprises a digital display.

6. A display device as defined in claim 1, wherein the input/output points (x_n, y_n) cover an input range over a linear scale representing 0-100% of the input and an output range over a linear scale representing 0-100% of the output.

7. A display device as defined in claim 1, wherein said personality means comprises programmed means for selecting a predetermined code to said computer means to identify and use the desired set of correlated input/output points.

8. A tank level receiver for use with liquid level measurement in irregularly shaped tanks, comprising a meter assembly housing associated with a tank the liquid level in which is to be monitored and displayed;

a display device for linearly displaying the liquid level in the irregularly shaped tank at an infinite number of points, said display device including input means for receiving digital data representative of a non-linear input variable;

computer means connected to said input means for receiving the digital data;

a substantially linear display having a display input connected to said computer means for providing an output indication which varies linearly with a signal applied to said display input;

non-volatile memory means connected to said computer means for storing a finite set of predetermined number n of correlated input/output points (x_n, y_n) which together define conversion function for converting a given input (x_n) at any given point (x_n, y_n) to an associated output (y_n) , each two adjacent points (x₀, y₀) and (x₁, y₁) defining a straight line segment, said computer means being programmed to interpolate for any given input x between two inputs (x₀, x₁) to provide an output (y) between associated outputs (y₀, y₁) by making the following computation;

##EQU6##

9. A tank level receiver as defined in claim 8, wherein the data is initially generated in analog form, and further comprising signal conditioning means for converting the analog data into digital data.

10. A tank level receiver as defined in claim 8, wherein said display comprises an analog meter.

11. A tank level receiver as defined in claim 8, wherein said display comprises a LED bar graph.

12. A tank level receiver as defined in claim 8, wherein said display comprises a digital display.

13. A tank level receiver as defined in claim 8, wherein the input/output points (x_n, y_n) cover an input range over a linear scale representing 0-100% of the input and an output range over a linear scale representing 0-100% of the output.

14. A tank level receiver as defined in claim 8, wherein said non-volatile memory means is arranged to store a plurality of finite sets of predetermined input/output points (x_n, y_n) each defining a conversion function for linearizing level variations in a specific tank;

and a personality means for selecting one of said plurality of sets of points for a specific tank conversion function.

15. A tank level receiver as defined in claim 14, personality means being arranged in said meter assembly housing, whereby insertion of a display device into said slot causes the personality means to automatically select the appropriate conversion function for the associated tank.

16. Method of linearly displaying a non-linear input variable at an infinite number of input points, comprising the steps of receiving digital data representative of a non-linear input variable;

providing computer means connected to said input means for receiving the digital data, providing an output indication on a substantially linear display having a display input connected to said computer means which varies linearly with a signal applied to said display input;

storing in a non-volatile memory means connected to said computer means a plurality of finite sets predetermined number n of correlated input/output points (x_n, y_n) each defining a specific conversion function representative of an associated non-linear input variable for converting a given input (x_n) at any given point (x_n, y_n) to an associated output (y_n) each two adjacent points (x₀, y₀) and (x₁, y₁) defining a straight line segment; and

interpolating in said computer means for any given input x between two inputs (x₀, x₁) to provide an output (y) between associated outputs (x₀, y₁) by making the following computation;

##EQU7## and selecting one of said plurality of sets of points for a given application for linearizing a predetermined specific non-linear input variable.

17. Method as defined in claim 16, wherein the method is used to monitor the liquid level in one of a plurality of tanks, and selecting one of said finite sets of predetermined correlated input/output points (x_n, y_n) which corresponds to the specific tank being monitored.

18. Method as defined in claim 16, further comprising the step of monitoring the liquid level in a tank, and generating digital data for inputting into the computer means which is a function of the level of liquid in the tank.