Fast technique for converting binary numbers into values expressed in an engineering unit format

• US 5,942,992 A
• Filed: 09/19/1997
• Issued: 08/24/1999
• Est. Priority Date: 11/15/1991
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Kelly, Christopher P. J.
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): WONG, ALBERT KANG
• Application Number:
  US08/933,717
• Time in Patent Office: 704 Days
• Field of Search: 340/870.21, 340/870.05, 340/870.17, 341/106, 341/165, 364/571.02, 364/571.04, 364/571.05, 364/571.07, 364/573, 364/577, 364/581, 364/553, 364/554, 364/723
• US Class Current: 340/870.21
• CPC Class Codes: G01D 3/022 having an ideal characteristic, map or correction data stored in a digital memory
• CPC Class Codes: G01D 3/0365 the undesired influence being measured using a separate sensor, which produces an influence related signal
• CPC Class Codes: G01K 1/028 arrangements for numerical indication
• CPC Class Codes: G01K 2219/00 Thermometers with dedicated analog to digital converters

Abstract

An engineering unit converter system for converting an analog measurement into an engineering value. An analog measurement of a physical quantity is transformed into a digital value. The digital value is then split into a high order digit and a lower order digit. The high order digit is used as an address to a memory device for fetching a line segment coefficient and a line segment offset coefficient. The lower order digit is multiplied with the line segment coefficient in a multiplier resulting in a product. The product is added to the line segment coefficient offset resulting in a sum whose value is an engineering unit.

One embodiment is directed to converting temperature measurements into engineering units via thermocouples. This embodiment includes: thermocouple devices, resistance thermal devices or positive temperature coefficient thermistors, adders, multipliers, and memory devices (readable and writable memory devices).

Claims

1. A system for converting a digital representation of a transducer output into a value expressed in an engineering unit format, said digital representation of a transducer output having low order bits and high order bits, said system comprising:

at least one memory device for storing a plurality of first and second coefficients;

a sequencer for enabling fetching of a first coefficient and a second coefficient from the plurality of first and second coefficients stored in the at least one memory device, said fetching being in response to the sequencer'"'"'s receipt of said high order bits of said digital representation of a transducer output;

a multiplier, under control of the sequencer, for multiplying a number identified by the low order bits of said digital representation of a transducer output with the first coefficient fetched from the at least one memory device, thereby producing a product; and

an adder, under control of the sequencer, for adding the product to the second coefficient fetched from the at least one memory device, thereby producing a value expressed in an engineering unit format.

2. The system of claim 1, wherein said multiplier and adder are floating point devices.

3. The system of claim 2, further comprising an additional memory device for storing a floating point look-up table, wherein:

the low order bits of said digital representation of a transducer output act as an addressing means for retrieving a floating point coefficient from the floating point look-up table of the additional memory device; and

the floating point coefficient serves as the number identified by the low order bits of said digital representation of a transducer output.

4. The system of claim 1, wherein:

the at least one memory device comprises a first memory device and a second memory device;

the first memory device is configured to store the plurality of first coefficients; and

the second memory device is configured to store the plurality of second coefficients.

5. The system of claim 4, further comprising a pipeline address control, under control of the sequencer, for providing addresses to the first and second memory devices so as to enable simultaneous processing of data fetched from said first and second memory devices.

6. The system of claim 1, wherein said multiplier and adder are integer devices.

7. The system of claim 1, wherein each of said at least one memory devices are random access memory devices.

8. The system of claim 1, wherein an actuation signal is provided to the sequencer each time a new digital representation of a transducer output is provided to the system.

9. The system of claim 4, wherein said multiplier and adder are floating point devices, and further comprising an additional memory device for storing a floating point look-up table, wherein:

the low order bits of said digital representation of a transducer output act as an addressing means for retrieving a floating point coefficient from the floating point look-up table of the additional memory device; and

the floating point coefficient serves as the number identified by the low order bits of said digital representation of a transducer output.

10. The system of claim 4, wherein said multiplier and adder are integer devices.

11. The system of claim 5, wherein said multiplier and adder are floating point devices, and further comprising an additional memory device for storing a floating point look-up table, wherein:

the low order bits of said digital representation of a transducer output act as an addressing means for retrieving a floating point coefficient from the floating point look-up table of the additional memory device; and

the floating point coefficient serves as the number identified by the low order bits of said digital representation of a transducer output.

12. The system of claim 5, wherein said multiplier and adder are integer devices.

13. The system of claim 1, wherein the number identified by the low order bits of said digital representation of a transducer output is equivalent to the low order bits of said digital representation of a transducer output.