Method and apparatus for calibration of sensors

• US 4,481,804 A
• Filed: 08/30/1982
• Issued: 11/13/1984
• Est. Priority Date: 09/04/1981
• Status: Expired due to Term

• Current Assignee: Hoffmann-La Roche Incorporated (Roche Holding AG)
• Original Assignee: Hoffmann-La Roche Incorporated (Roche Holding AG)
• Inventors: Eberhard, Patrick, Palma, Jean-Pierre, Mindt, Wolfgang, Schafer, Robert, Scharf, Robert
• Primary Examiner(s): Kreitman, Stephen A.
• Assistant Examiner(s): Chapman, Jr., John E.
• Application Number:
  US06/413,045
• Time in Patent Office: 806 Days
• Field of Search: 73/1 G, 73/1 R, 204/1 T, 204/1 P, 204/400, 204/406, 204/415, 128/635, 128/204.22, 364/571, 324/74, 324/425
• US Class Current: 73/1.06
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1477 non-invasive
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: G01N 27/4163 checking the operation of, or calibrating, the measuring apparatus G01N27/3274, G01N27/4175 and G01N33/0006 take precedence

Abstract

Calibration of sensors of the type used for the cutaneous determination of blood oxygen and carbon dioxide levels is facilitated by providing separate sensor units, alternatively and removably connectable to a calibration device and to the measuring devices with which they are used for such determinations. The sensor units contain, in addition to a sensor electrode, a data memory in which is stored calibration data generated when the sensor unit is connected to the calibration device. The calibration device can provide a plurality of calibration stations, each capable of supplying a standard gas to a connected sensor and, in response to signals from the sensor exposed to the standard gas, generating data signals representing the calibration of the sensor, which signals are transmitted to the data memory of the sensor unit. Upon connection of the sensor unit to the measuring device, the calibration data from the data memory of the sensor unit are used as a calibration base for measurements by the sensor.

Claims

1. A method for determining the partial pressure of a sample gas by means of a sensor wherein said sensor is initially exposed to a standard reference gas for calibration and thereafter to said sample gas for measurement, said method comprising the steps of:

(a) providing as apparatus for the conduct of said determination

(1) an independent and separate sensor unit which includes a partial pressure sensor and a data memory device.

(2) an independent and separate calibration device, and

(3) an independent and separate measuring device for receiving and processing measurement signals from said partial pressure sensor when said sensor is exposed to a sample gas;

said sensor unit being removably connectable alternatively to either said calibration device or to said measuring device, wherein said calibration device, when connected to said sensor unit, generates calibration data in response to exposure of said partial pressure sensor to said standard reference gas and transfers said calibration data to said data memory device of said sensor unit, and wherein said measuring device, when connected to said sensor unit, receives said calibration data from said data memory device and utilizes said calibration data in the processing of measurement signals from said partial pressure sensor;

(b) connecting said sensor unit to said calibration device and, while so connected, exposing said partial pressure sensor to said standard reference gas and storing in said data memory device of said sensor unit calibration data generated by said calibration device; and

(c) thereafter disconnecting said sensor unit from said calibration device, connecting it to said measuring device, allowing the transfer of calibration data from said data memory device to said measuring device and, while said sensor unit is so connected, exposing said partial pressure sensor to said sample gas so that said sensor provides measurement data to said measuring device.

2. The method of claim 1 wherein said partial pressure sensor is a cutaneous sensor for cutaneous determination of levels of one or more of oxygen and carbon dioxide in the blood.

3. A system for determining the partial pressure of a sample gas, said system comprising:

(1) an independent and separate sensor unit which includes a partial pressure sensor and a data memory device,

(2) an independent and separate calibration device; and

(3) an independent and separate measuring device for receiving and processing measurement signals from said partial pressure sensor when said sensor is exposed to a sample gas;

said sensor unit being removably connectable alternatively to either said calibration device or to said measuring device, wherein, said calibration device, when connected to said sensor unit, generates calibration data in response to exposure of said partial pressure sensor to said standard reference gas and transfers said calibration data to said data memory device thereof, and wherein said measuring device, when connected to said sensor unit, receives said calibration data from said data memory device and utilizes said calibration data in the processing of measurement signals from said partial pressure sensor.

4. A calibration device for use with a sensor unit including a partial pressure sensor and data memory means, wherein a sensor unit is removably connectable either to said calibration device or to a separate measurement device, said calibration device comprising:

separable connector means for allowing a sensor unit to be operatively but removably connected to said calibration device, in order to permit the transfer of signals therebetween;

measuring circuit means for receiving the signal generated by the partial pressure sensor of a sensor unit connected to said calibration device and for generating an output in response thereto;

processing circuit means for evaluating the output generated by said measuring circuit and for generating calibration data in response thereto; and

control circuit means for transferring said calibration data to the data memory means of said sensor unit.

5. A calibration device in accordance with claim 4 which further includes station means for exposing the partial pressure sensor of a sensor unit connected to said calibration device to a standard reference gas.

6. A sensor unit for use in conjunction with a measuring device for measuring the partial pressure of a gas, said unit comprising:

a partial pressure sensor;

data memory means; and

separable connector means for allowing the operative but removable connection of said sensor unit to either a separate calibrating device or to a separate measuring device, in order to permit the transfer of signals therebetween;

wherein, when said sensor unit is connected to said calibration device, said data memory means thereof is capable of receiving and storing calibration data pertaining to said partial pressure sensor which is generated by said calibration device upon exposure of said sensor to a standard reference gas; and

further wherein, when said sensor unit is thereafter connected to said measuring device said data memory means is capable of transferring said calibration data stored therein to said measuring device, which utilizes said calibration data in processing measurement signals from said partial pressure sensor.

7. A sensor unit according to claim 6 wherein said data memory means is mounted within said separable connector means.

8. A sensor unit according to claim 6 wherein said connector means is a multiple contact element, separable electrical connector.

9. A sensor unit according to claim 6 wherein said partial pressure sensor is a cutaneous sensor for cutaneous determination of levels of one or both of oxygen and carbon dioxide in the blood.