Cold-junction-compensated input terminal of a thermocouple instrument

Patent metadata

Field	Value
Publication number	US-9995638-B2
Application number	US-201514871041-A
Country	US
Kind code	B2
Filing date	Sep 30, 2015
Priority date	Apr 30, 2015
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

Input terminal of a thermocouple (TC) instrument. The input terminal may include a printed circuit board (PCB), including an input portion configured to receive signals from a thermocouple, and an output portion configured to communicatively connect to the instrument. The input terminal may further include a sensor mounted on the PCB, configured to measure temperature at or near a cold junction of the input terminal. The PCB may include first traces connecting the input portion of the PCB to the output portion of the PCB, and configured to send TC signals to the TC instrument and second traces connecting the sensor to the output portion of the PCB, and configured to send temperature signals to the instrument. The traces may be configured to provide the TC signals and the temperature signals to the TC instrument without using metal pins.

First claim

We claim:

1. An input terminal of a thermocouple (TC) instrument, comprising:
a printed circuit board (PCB);
a thermal sensor, mounted on the PCB, and configured to measure temperature at or near a cold junction of the input terminal; and
a TC receptacle portion, coupled to the PCB, and configured to receive a mating TC plug;
wherein the PCB comprises:
an input portion, configured to receive TC signals from a thermocouple; and
an output portion, configured to communicatively connect to the TC instrument;
first traces connecting the input portion of the PCB to the output portion of the PCB, and configured to send the TC signals to the TC instrument; and
second traces connecting the thermal sensor to the output portion of the PCB, and configured to send temperature signals to the TC instrument; and
wherein the traces at the output portion of the PCB implement a plurality of PCB implemented pins configured to provide the TC signals and the temperature signals to the TC instrument without using metal pins.

2. The input terminal of claim 1 ,
wherein the PCB implemented pins are configured to connect directly to another PCB in the thermocouple instrument.

3. The input terminal of claim 2 ,
wherein the PCB implemented pins comprise PCB tabs with respective traces that are configured to connect directly to corresponding slots or holes in the other PCB in the thermocouple instrument.

4. The input terminal of claim 3 ,
wherein the PCB tabs with respective traces implement a card edge style connector.

5. The input terminal of claim 1 ,
wherein the PCB includes one or more mounting holes, each mounting hole comprising a respective pad configured to receive a mounting screw and to provide electrical connections for the TC signals from the TC receptacle portion to the PCB.

6. The input terminal of claim 5 ,
wherein at least one mounting hole is configured to provide a low thermal impedance from the TC receptacle portion to the PCB.

7. The input terminal of claim 6 ,
wherein a mounting screw of the at least one mounting hole is proximate to the cold junction, and wherein the thermal sensor is situated proximate to the mounting screw, thereby providing for accurate measurement of temperature near the cold junction.

8. The input terminal of claim 1 ,
wherein the PCB implemented pins are configured to facilitate direct insertion into a host or main PCB via a wave process.

9. The input terminal of claim 1 ,
wherein the PCB implemented pins are configured to connect indirectly to another PCB in the thermocouple instrument via a receptacle of the thermocouple instrument.

10. The input terminal of claim 1 , further comprising:
a housing, wherein one or more of the PCB and the thermal sensor are included in the housing.

11. The input terminal of claim 1 , wherein the PCB extends into the TC receptacle portion, wherein the extension of the PCB includes at least two pads, thereby providing electrical connections for the mating TC plug without using additional connection elements.

12. The input terminal of claim 11 ,
wherein the TC receptacle portion comprises one or more springs configured to provide reliable retention of, and electrical connection to, the mating TC plug.

13. The input terminal of claim 12 ,
wherein the TC receptacle portion further comprises one or more spring alignment features configured to hold the one or more springs in place.

14. The input terminal of claim 11 ,
wherein the thermal sensor is mounted on the input portion of the PCB proximate to one of the at least two pads.

15. The input terminal of claim 11 ,
wherein the thermal sensor comprises an integrated circuit that is mounted on one of the at least two pads.

16. A method, comprising:
receiving, to an input portion of a printed circuit board (PCB) of an input terminal of a thermocouple (TC) instrument, a TC signal from a thermocouple, wherein the PCB comprises:
first traces connecting the input portion of the PCB to an output portion of the PCB; and
second traces connecting a thermal sensor mounted on the PCB to the output portion of the PCB, wherein the second traces at the output portion of the PCB implement a plurality of PCB implemented pins;
measuring, by the thermal sensor, temperature at or near a cold junction of the input terminal;
sending, via the first traces, the TC signals to the TC instrument; and
sending, via the second traces, temperature signals to the TC instrument;
wherein said sending the TC signals and said sending the temperature signals are performed without using metal pins.

17. The method of claim 16 ,
wherein the PCB implemented pins are configured to connect directly to another PCB in the thermocouple instrument.

18. The method of claim 16 ,
wherein the PCB implemented pins are configured to facilitate direct insertion into a host or main PCB via a wave process.

19. The method of claim 16 , further comprising:
receiving, to a TC receptacle portion of the input terminal, a mating TC plug, wherein the PCB extends into the TC receptacle portion and includes at least two pads; and
conducting, via the at least two pads, the TC signals from the mating TC plug to the first traces without using additional connection elements.

20. The method of claim 19 ,
wherein the thermal sensor comprises an integrated circuit that is mounted proximate to one of the at least two pads.

Assignees

• Nat Instruments Corp

Inventors

• Ousley Daniel H
• Stelley Shaun M
• Pasternak David R

Classifications

• G01K7/13 Primary

  Circuits for cold-junction compensation · CPC title