Self-calibrating instrumentation system with multiple sensor modules

• US 5,377,128 A
• Filed: 10/05/1993
• Issued: 12/27/1994
• Est. Priority Date: 11/25/1992
• Status: Expired due to Fees

• Current Assignee: Ronald V. Mcbean
• Original Assignee: Ronald V. Mcbean
• Inventors: McBean, Ronald V.
• Primary Examiner(s): Voeltz, Emanuel T.
• Assistant Examiner(s): MILLER, CRAIG S
• Application Number:
  US08/132,848
• Time in Patent Office: 448 Days
• Field of Search: 364/550, 364/557, 364/558, 364/571.01, 364/571.02, 364/571.03, 364/571.04, 364/571.07, 73/1 R
• US Class Current: 702/91
• CPC Class Codes: A61B 2017/00482 with a code
• CPC Class Codes: G01B 2210/60 Unique sensor identification
• CPC Class Codes: G01D 3/022 having an ideal characteristic, map or correction data stored in a digital memory

Abstract

An instrumentation system includes a hand-held computer-based measuring meter having a visual display and a plurality of individual sensor modules that can be selectively coupled to the measuring meter for measuring one of a variety of parameters such as temperature, pressure, or the like. Each sensor module includes a sensor responsive to a particular stimulus, as well as a data memory for storing information about the sensor. When the sensor module is interconnected with the measuring meter, the measuring meter accesses the memory of the sensor module to input data corresponding to sensor type, an accuracy code, calibration point data, and a calibration date code. The measuring meter compares the calibration date code to the current date to determine whether the sensor module requires recalibration. The measuring meter uses the accuracy code data to determine the number of significant digits displayed by the visual display. The measuring meter uses the sensor type code and calibration points to calibrate the measuring meter relative to the sensor module and to select the algorithm used to compute the current value measured by the sensor module.

Claims

1. A self-calibrating instrumentation apparatus for use with a plurality of sensor modules of different types for sensing and measuring a plurality of parameters;

comprising in combination;

a. a first sensor module of a first sensor type including a first sensor responsive to a first condition for generating a first electrical signal indicative of such first condition, said first sensor module also providing a sensor type code for identifying said first sensor module as being of said first sensor type;

b. a second sensor module of a second sensor type different from said first sensor type and including a second sensor responsive to a second condition for generating a second electrical signal indicative of such second condition, said second sensor module also providing a sensor type code for identifying said second sensor module as being of said second sensor type;

c. central processor means responsive to electrical signals generated by said first sensor module and by said second sensor module for computing a measurement sensed by said first sensor module and by said second sensor module;

d. display means coupled to said central processor means for numerically displaying the measurement computed by said central processor means;

e. means for selectively coupling one of said first and second sensor modules to said central processor;

f. each of said first and second sensor modules including a memory;

g. the memory of said first sensor module storing calibration data indicative of the magnitude of the electrical signal generated by said first sensor module at first and second known conditions;

h. the memory of said second sensor module storing calibration data indicative of the magnitude of the electrical signal generated by said second sensor module at first and second known conditions;

i. said central processor means accessing and being responsive to the calibration data stored in the memory of the selected sensor module that is coupled to said central processor means for calibrating said central processor means when computing the measurement sensed by the selected sensor module, said central processor being further responsive to the sensor type code of the selected sensor module for selecting an algorithm used to compute the measured value of the parameter being sensed by the selected sensor module relative to the calibration data accessed from the memory of the selected sensor module, said central processor means computing the measurement sensed by said first sensor module in accordance with a first predetermined algorithm, and said central processor means computing the measurement sensed by said second sensor module in accordance with a second predetermined algorithm difference from the first predetermined algorithm.

2. The instrumentation apparatus recited by claim 1 wherein each of said first and second sensor modules provides its respective electrical signal as an analog signal, and wherein said central processor means includes an analog-to-digital converter for converting the analog signal to a digital signal.

3. The instrumentation apparatus recited by claim 1 wherein each of the memories of said first and second sensor modules stores said calibration data and said sensor type code as digital signals.

4. The instrumentation apparatus recited by claim 3 wherein each of the memories of said first and second sensor modules stores at least a first calibration data word at a first memory address and a second calibration data word at a second memory address, and wherein said central processor means addresses the memory of the selected sensor module to access both the first calibration data word and the second calibration data word.

5. The instrumentation apparatus recited by claim 3 wherein each of the memories of said first and second sensor modules is an erasable programmable memory for allowing each sensor module to be recalibrated at selected intervals.