Infrared temperature sensor

• US 5,169,234 A
• Filed: 02/13/1991
• Issued: 12/08/1992
• Est. Priority Date: 02/13/1990
• Status: Expired due to Fees

• Current Assignee: Ultrakust Electronic GmbH Sudetenstrasse
• Original Assignee: Ultrakust Electronic GmbH
• Inventors: Bohm, Alfred
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): BENNETT, GEORGE B
• Application Number:
  US07/655,532
• Time in Patent Office: 664 Days
• Field of Search: 374/120, 374/121, 374/126, 374/127, 374/128, 374/130, 374/132, 374/133, 364/557, 356/43, 356/44, 250/338.1
• US Class Current: 374/128
• CPC Class Codes: G01J 5/10 using electric radiation detectors
• CPC Class Codes: G01J 5/12 using thermoelectric elements, e.g. thermocouples

Abstract

An infrared temperature sensor with a sensor element sensitive for infrared radiation and which generates an analog output signal, permits a speed-variable and resolution-variable infrared temperature measurement, in that at least one resolution-adjustable converter means is provided for converting the analog signal into a digital signal and in that a digital signal processing means is provided for the program-controlled linearization and evaluation of the digital signal.

Claims

1. An infrared temperature sensor comprising:

a sensor element sensitive to infrared radiation, which generates an analog output-signal;

at least one converter means for converting said analog output-signal into a digital signal; and

a digital signal processing means for a program-controlled linearization and evaluation of said digital signal,

said converter means comprising a voltage-frequency converter and an adjustable frequency counter, being series-connected to each other for adjusting resolution and measuring range of the temperature sensor.

2. An infrared temperature sensor according to claim 1, wherein the frequency counter is programmable.

3. An infrared temperature sensor according to claim 2 having a temperature sensor in thermal contact with the sensor element and which generates a temperature-dependent reference junction signal.

4. An infrared temperature sensor according to claim 1, wherein a control voltage source is provided for generating a reference signal.

5. An infrared temperature sensor according to claim 1, wherein the signal processing means has an analog-digital converter as an additional input for measured signals.

6. An infrared temperature sensor according to claim 1, wherein the signal processing means has a microprocessor with a computing and control logic.

7. An infrared temperature sensor according to claim 1, wherein the signal processing means has a memory for providing linearization and calibration data for measured signals.

8. An infrared temperature sensor according to claim 7, wherein the memory is programmable.

9. An infrared temperature sensor according to claim 1, wherein the signal processing means has an internal bus for inputting and outputting signals and control quantities.

10. An infrared temperature sensor according to claim 1, wherein the signal processing means has a connection for an external bus system for inputting and outputting by means of which the signal processing means is in particular controllable and programmable.

11. An infrared temperature sensor according to claim 10, wherein a central program and control unit is connected to the external bus system.

12. An infrared temperature sensor according to claim 10, wherein the connection has an optical coupler.

13. An infrared temperature sensor according to claim 10, wherein the connection has an interface module, which is connected to a bus system with a two-wire line.

14. An infrared temperature sensor according to claim 13, wherein the two-wire line is constructed both for energy and data transmission.

15. An infrared temperature sensor according to claim 1, wherein a power supply for the digital processing means has a d.c.-d.c. converter for isolation from mains.

16. An infrared temperature sensor according to claim 1, wherein the signal processing means has an infrared transmitting-receiving element for remote polling.

17. An infrared temperature sensor according to claim 16, wherein a buffer store is provided for storing a larger number of measured values between the remote polls.

18. An infrared temperature sensor according to claim 1, wherein a measuring process or a measuring sequence can be started via an externally supplied trigger signal.

19. An infrared temperature sensor according to claim 1, wherein the signal processing means has a microprocessor with a computing and control logic, a memory for providing linearization and calibration data for measured signals, an internal bus for inputting and outputting signals and control quantities and a connection for an external bus system for inputting-outputting, by means of which the signal processing means can in particular be controlled and programmed.

21. An infrared temperature sensor according to claim 9, wherein the analog output signal of the sensor element, the reference junction signal and optionally the reference signal are alternately applied to the input of the converter means.

22. An infrared temperature sensor according to claim 19, wherein there is a program-controlled switching for the distribution of the measured signals to inputs of the signal processing means.

23. An infrared temperature sensor according to claim 19 with an input for a contact thermometer for determining the temperature of a measurement object and for emission factor determination.

24. An infrared temperature sensor according to claim 19, wherein the memory is programmable.

25. An infrared temperature sensor according to claim 19, wherein the connection has an optical coupler.

26. An infrared temperature sensor according to claim 19, wherein the signal processing means has an infrared transmitting-receiving element for remote polling.

27. An infrared temperature sensor according to claim 26, wherein a buffer store is provided for storing a larger number of measured values between the remote polls.

28. An infrared temperature sensor according to claim 19, wherein a measuring process or a measuring sequence can be started by means of an externally supplied trigger signal.

20. An infrared temperature sensor, comprising a sensor element sensitive for infrared radiation, for generating an analog output signal, at least one converter means adjustable with regards its resolution and its measuring range for converting the analog output signal into a digital signal, the converter means comprising a voltage-frequency converter and a series-connected adjustable frequency counter, a digital signal processing means for the program-controlled linearization and evaluation of the digital signal, a temperature sensor in thermal contact with the sensor element for generating a temperature-dependent reference junction signal and a control voltage source for generating a reference signal.