Thermocouple linearizer circuit

• US 4,179,745 A
• Filed: 05/30/1978
• Issued: 12/18/1979
• Est. Priority Date: 05/30/1978
• Status: Expired due to Term

• Current Assignee: Gentran Incorporated
• Original Assignee: Gentran Incorporated
• Inventors: Wuertele, James W.
• Primary Examiner(s): Morrison, Malcolm A.
• Assistant Examiner(s): Chin, Gary
• Application Number:
  US05/910,766
• Time in Patent Office: 567 Days
• Field of Search: 364/571, 364/573, 364/557, 364/852, 73/362 R, 73/362.4, 73/362.7, 73/361, 73/359 R, 73/1 F, 73/362 AR, 73/765, 324/105, 324/130, 328/156, 328/162, 328/184, 307/229, 307/231, 307/263
• US Class Current: 702/86
• CPC Class Codes: G01K 7/14 Arrangements for modifying the output characteristic, e.g. linearising

Abstract

A thermocouple linearizer circuit for use in a device for digitally displaying the temperature of a thermocouple. The circuit includes a plurality of proportional correction means, each connected to receive a non-linear electrical signal representing the temperature of a thermocouple. The correction circuits generate a correction signal proportional to the difference between a non-linear electrical signal and a predetermined reference signal. The correction signals are initiated when the non-linear signal exceeds the respective reference signal in each correction circuit. An arithmetic unit is included for adding the correction signals and the non-linear signal thereby forming a signal corresponding to a linear function of the temperature of the thermocouple.

Claims

1. A thermocouple linearizer circuit comprising:

proportional correction means connected to receive a non-linear electrical signal representing the temperature of a thermocouple for generating a linearization correction signal proportional to the difference between said electrical signal and a first predetermined reference signal, said linearization correction signal being generated when said electrical signal exceeds said reference signal, and

arithmetic means for adding said correction signal and said electrical signal thereby forming a linear signal corresponding to the temperature of said thermocouple.

2. A thermocouple linearizer circuit for use in a digital display device comprising:

a plurality of proportional correction means connected to receive a non-linear electrical signal, each of said linearization correction means including means for generating a correction signal proportional to the difference between said non-linear signal and a predetermined reference signal, said linearization correction signals being generated when said non-linear signal exceeds said reference signal, and

arithmetic means for adding said correction signals and said non-linear signals thereby forming a linear signal corresponding to the temperature of said thermocouple.

3. A circuit as in claim 2 further including amplifier means connected to receive said non-linear electrical signal for amplifying said electrical signal thereby forming an amplified non-linear signal.

4. A circuit as in claim 3 wherein each of said correction means includes first trimmer means for generating said reference signal,

second amplifier means connected to receive said reference signal and to receive said amplified non-linear signal for initiating said correction signal,

second trimmer means connected to said second amplifier means for controlling the value of said proportional correction signal, and

diode means connected to said second amplifier means and to said second trimmer means for preventing said correction signal when said electrical signal is below said reference signal.

5. A circuit as in claim 3 wherein said arithmetic means includes means for adding the correction signals from each of said correction means.

6. A circuit as in claim 3 wherein said arithmetic means includes means for subtracting said correction signals from each of said correction means.

7. A linearizer circuit comprising:

proportional correction means connected to receive a non-linear electrical signal representing the temperature of a thermocouple for generating a correctional signal proportional to the difference between said non-linear signal and a first predetermined reference signal, said linearization correction signal being generated when said non-linear signal exceeds said reference signal, and

arithmetic means for adding said correction signal and said non-linear signal thereby forming a linear signal corresponding to said electrical signal.

8. In a thermocouple linearizer circuit for use in a digital display device, the method comprising the steps of:

generating a linearization correction signal proportional to the difference between a non-linear electrical signal representing the temperature of a thermocouple and a first predetermined reference signal, said correctional signal being generated when said electrical signal exceeds said reference signal, and

adding said linearization correction signal and said electrical signal thereby forming a linear electrical signal corresponding to the temperature of said thermocouple.