TEMPERATURE SENSOR HAVING MEANS FOR IN-SITU CALIBRATION

• US 20130022075A1
• Filed: 07/18/2012
• Published: 01/24/2013
• Est. Priority Date: 07/18/2011
• Status: Abandoned Application

• Current Assignee: ABB Technology AG (ABB Limited)
• Original Assignee: ABB Technology AG (ABB Limited)
• Inventors: PAPE, Detlef, MADONNA, Gian-Luigi, MARET, Yannick
• Application Number:
  US13/552,300
• Publication Number:
  US 20130022075A1
• Time in Patent Office: Days
• US Class Current: 374/1
• CPC Class Codes: G01K 15/005 Calibration
• CPC Class Codes: G01K 7/16 using resistive elements resistive elements per se H01C, H01L
• CPC Class Codes: G01K 7/30 using thermal noise of resistances or conductors

Abstract

A temperature sensor is disclosed as having a resistance thermocouple, accommodated in a sensor housing, for detecting a process temperature. The thermocouple can be connected via a multipole electric line to an electronic temperature transmitter for measured-value conditioning, the resistance thermocouple being equipped for in-situ calibration with a Johnson noise thermometer for determination of a reference temperature.

Claims

1. A temperature sensor comprising:

a resistance thermocouple accommodated in a sensor housing, for detecting a process temperature; and

a multipole electric line for connecting the thermocouple to an electronic temperature transmitter for measured-value conditioning, the resistance thermocouple being equipped with means for in-situ calibration, wherein the means for in-situ calibration includes a Johnson noise thermometer for determination of a reference temperature.

2. The temperature sensor as claimed in claim 1, wherein the means for in-situ calibration comprise:

a current buffer unit for covering a temporary multicurrent during a calibration cycle via the Johnson noise thermometer

3. The temperature sensor as claimed in claim 1, wherein the multipole electric line is designed as a 30 mW line.

4. The temperature sensor as claimed in claim 1, wherein the multipole electric line is embodied using four-wire technology.

5. The temperature sensor as claimed in claim 1, wherein the multipole electric line is embodied as a multipole shielded line at whose distal end the resistance thermocouple is arranged in an integrated fashion.

6. The temperature sensor as claimed in claim 1, wherein the Johnson noise thermometer is accommodated in a separate calibration unit that is fitted on the sensor housing.

7. The temperature sensor as claimed in claim 6, wherein the separate calibration unit is arranged between the sensor housing and the electronic temperature transmitter via a connection unit, the multipole electric line being guided through the connection unit.

8. The temperature sensor as claimed in claim 6, wherein the calibration unit is connected electrically in parallel to the resistance thermocouple via the connection unit, the connection unit being configured for a normal mode as a bypass relative to the temperature transmitter and being connected to the resistance thermocouple in a calibration mode for measuring a noise current in a defined bandwidth for determining calibration data.

9. The temperature sensor as claimed in claim 8, wherein the connection unit comprises:

switching means for switching between the normal mode and the calibration mode.

10. The temperature sensor as claimed in claim 1, wherein the temperature transmitter is configured for determining noise voltages induced in shielding of the resistance thermocouple, for correcting spectral density of a measurement current of the Johnson noise thermometer.