CA1069337A - Cold junction thermocouple compensator - Google Patents
Cold junction thermocouple compensatorInfo
- Publication number
- CA1069337A CA1069337A CA247,822A CA247822A CA1069337A CA 1069337 A CA1069337 A CA 1069337A CA 247822 A CA247822 A CA 247822A CA 1069337 A CA1069337 A CA 1069337A
- Authority
- CA
- Canada
- Prior art keywords
- thermocouple
- compensator
- junction
- connector
- cold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
- G01K7/10—Arrangements for compensating for auxiliary variables, e.g. length of lead
- G01K7/12—Arrangements with respect to the cold junction, e.g. preventing influence of temperature of surrounding air
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Thermistors And Varistors (AREA)
- Battery Mounting, Suspending (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
- Thermally Actuated Switches (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A cold junction compensator provides the electrical equivalent of an ice-bath reference thermocouple, at a selected temperature, for example 0°C. Input connectors, for engagement with conventional thermocouple units, form thermocouple junctions with conductors connected to a battery-operated Wheatstone bridge circuit adapted to supply an equal and opposite voltage output compensating for variations in the thermocouple junction output at different ambient temperatures. The compensator may be included in a module having input sockets or input plugs to coact with plugs or sockets of conventional thermocouple units.
The compensator and battery may be encapsulated, or an accessible switch may be included in the battery circuit.
A cold junction compensator provides the electrical equivalent of an ice-bath reference thermocouple, at a selected temperature, for example 0°C. Input connectors, for engagement with conventional thermocouple units, form thermocouple junctions with conductors connected to a battery-operated Wheatstone bridge circuit adapted to supply an equal and opposite voltage output compensating for variations in the thermocouple junction output at different ambient temperatures. The compensator may be included in a module having input sockets or input plugs to coact with plugs or sockets of conventional thermocouple units.
The compensator and battery may be encapsulated, or an accessible switch may be included in the battery circuit.
Description
10~33'7 TITLE OF THE INVENTI~N
COLD JtJNCTION TMERMOCOUPLF COMPENS~TOR
SPECIFICATION
This invention relates to a cold junction com~ensator for use in the~mocouple circuits.
BACKGROUND OF THE I~IF,N~I~N
In thermocouple circuits it is necessary, for certain measurements, to utilise two identical thermocouples and, whilst keeping one at a reference temperature, to use the other to sense the temperature of an environment to be investigated. Under laboratory conditions, the temperature of the first thermocouple is usually maintained at ice point ~0C) by use of an ice-bath, or at some higher fixed temperature by means of a temperature-controlled oven, and the first thermocouple is usually known as the reference or "cold junction". The other thermocouple is inserted in the environment under investigation and is known as the "sensing junction" or "hot junction". The known conventional methods for maintaining the first temperature-controlled junction at a constant temperature are satisfactory for use under laboratory conditions, but are impractical in terms of weight, size, cost, power consumption, maintenance, warm-up time, and ice replacement or contamination, in many industrial applications, and especially in aircraft and missile applications.
OBJ~CTS OF TH~ INVFNTION
.
It is the main object of the present invention to provide a cold junction compensator, for use in thermocouple circuits, which provides the physical and electrical 3~ equivalent of an ice-bath reference thermocouple at 0C.
COLD JtJNCTION TMERMOCOUPLF COMPENS~TOR
SPECIFICATION
This invention relates to a cold junction com~ensator for use in the~mocouple circuits.
BACKGROUND OF THE I~IF,N~I~N
In thermocouple circuits it is necessary, for certain measurements, to utilise two identical thermocouples and, whilst keeping one at a reference temperature, to use the other to sense the temperature of an environment to be investigated. Under laboratory conditions, the temperature of the first thermocouple is usually maintained at ice point ~0C) by use of an ice-bath, or at some higher fixed temperature by means of a temperature-controlled oven, and the first thermocouple is usually known as the reference or "cold junction". The other thermocouple is inserted in the environment under investigation and is known as the "sensing junction" or "hot junction". The known conventional methods for maintaining the first temperature-controlled junction at a constant temperature are satisfactory for use under laboratory conditions, but are impractical in terms of weight, size, cost, power consumption, maintenance, warm-up time, and ice replacement or contamination, in many industrial applications, and especially in aircraft and missile applications.
OBJ~CTS OF TH~ INVFNTION
.
It is the main object of the present invention to provide a cold junction compensator, for use in thermocouple circuits, which provides the physical and electrical 3~ equivalent of an ice-bath reference thermocouple at 0C.
- 2 - ~
. ~Ofà9;~3'7 ~ nother object of the invention is to provide an extremely versatile cold junction compensator which is no longer than a conventional quick-disconnect thermocouple connector and which is readily portable.
A still further object of the invention is to provide a cold junction compensator which can operate on a replace-able button-type self-contained mercury battery.
SU~RY OF THE INVENTIOM
~ccording to the present invention, a cold junction compensator comprises:-ti) a first input connector for connection to a first element of a sensing thermocouple, said first connector being made of one material of a thermo-couple junction;
(ii) a second input connector for connection to a second element of said sensing thermocouple, said .
second connector being made of said one material of a thermocouple junction;
(iii) a first conductor forming a thermocouple junction with said first connector;
(iv) a second conductor forming a thermocouple junction with said second connector;
(v) first and second output terminals;
(vi) an electrical connection between said first conductor and said first output terminal;
(vii) a voltage generator circuit between said second conductor and said second output terminal, said generating circuit being constructed such that, over a range of temperature, the voltage generated at any temperature is equal an~ opposite to the .. . .
10f;9~3'7 voltage differential generated by said thermo-couple junction~ at that temperature.
In a preferred form, the voltage generating circuit is a ~?heatstone bridge circuit including a supply battery, one arm including resistance elements whose value varies with variation of temperature, such as for exanple Thermistors.
Conveniently, the compensator is incorporated in a module in which the input connectors form or are incorporated in plugs or sockets for use respectively with a conventional female or male plug connector thermo-couple unit.
An important advantage may be gained in the invention by computer selection of resistors for the bridge circuit, to match the characteristics of a closely-matched pair of Thermistors which have the same or approxi-mately the same temperature-resistance curve, say within .2C interchangeability, or most preferably within .1C
interchangeability.
A further advantageous feature of the invention is the possibility of substitution of the resistor portions of the circuit, e.g by plugging in alternative units, to permit the same matched pair of Thermistors to be used for different circuits and metal-metal combinations.
A still further advantageous feature of the invention is the po~sibility of substitution of the Thermistor portion of the circuit, as well as or alternatively to the substitu-tion of the resistor portion of the circuit.
The power supply for the voltage generating circuit is conveniently obtained from a primarv hattery, and at lOfi:9;~3~7 least the battery and circuit may be encapsulated.
Alternatively, switch means may be included in the battery circuit.
The above and other ohjects, features and advantages will be apparent from the following descrip-tion of an embodiment of cold junction compensator with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAI.A~INGS
Figure 1 is a perspective elevation sho~ing a cold-junction compensator module with sockets adapted to receive the pins of a male connector;
Figure 2 is a perspective elevation showing a compensator module arranged having male pins for engagement in a female connector;
Figure 3 is a perspective view of a compensator module, with cover portions shown separated, and with pins omitted;
Figure 4 is a circuit program of the internal compon-ents and connections of the compensator of any of Figures 1, 2 and 3.
Dl~:SCRIPTION OF TH~ PRE~P~P~F.D ~3~C)DIMENT
Referring firstly to Figure 4, the unit has terminals 1 and 2 for receiving the input from a sensing thermocouple TH. Conductors la and 2a are both made of the sa~e thermo-couple alloy, and conductors lb and 2_ are both made of copper. Conductor 2a connects terminal 2 to a thermocouple junction J6' and conductor 2_ connects ~unction J~ directly to an output terminal 3 of a pair of output terminals 3, 4 connected to a measuring instrument or recorder ~. Conductor la connects terminal 1 to a thermocouple junction J~, and 10~
conductor lb connects junction J5 to a bridge circuit.
Conductor 4b, of copper, connects the bridge circuit to output terminal 4. Thermocouple junctions J5 and J~ are formed between the thermocouple alloy conductors la and 2a and the copper conductors l_ and 2_.
One arm of the hridge is constituted by resistors R2, R5 and variable resistor P in series, and the other arm of the bridge is constituted by two Thermistors Tl and T2 and shunt resistor D. ~ resistor ~6 is connected centrally across the bridge, and provides an output to conductors l and 4b. A battery B is connected in series with resistor Rl to the ends of the bridge.
Values of the resistors Rl, R2~ R5, R6, and D are shown in the following takle for various thermocouple pairs:
~ . .
S~ a~
a) ~ ~ , ~ ;r Q~ ~ u~~1 O O r-i~D ~ ~1 ~) ~
, . .. ___ __ a~ ~ ~ ~ . ' ~ ~ ~ ~ ~ O ~D ' C~ ~ U~00 ~ O
'~ ~
r- , ~ ~ ~ .Y~ O ~
.,1 ,1 0 O ~er ~ In r-l 1 a~ ~ r~
. ~ _ ___.
_~ .Y
~9 ~
~ a) ~ ~ ~ ~r co O ~j I~ D ~
u~
\V
~ ,y O ~r 1~ U~ U~~-1 In 5 O ~ ~ *
$
u~ ~ ~ In ~
_ . , I
l(J~ 37 Thermistors Tl and T2 = (e.g. YSl A4031 lOk @ 25C, or Y~l 44006) or any equivalent Thermistor pair having the same temperature or resistance characteristics.
B is a single cell battery, such as a "Mallory" PK625. P
is a variable resistor - 50 ohms.
The system incorporates two temperature sensitive elements ~Thermistors) which are thermally integrated ~ith the cold junctions 5 and 6. The circuit is energized from the battery B. The output voltage across register R6 is proportional to the unbalance created between a pre-set equivalent electronic reference temperature and the temperature of a hot junction. In this syste~, the reference temperature ~C may be chosen.
Since the cold junctions are subjected to ambient temperature, a thermally generated voltage is produced therein. This voltage would appear as an error voltage unless compensated for. This is accomplished by auto-matically injecting into the circuit an equal and opposite voltage. This cancels the error voltage and maintains the electrical equivalent of a static refere~ce junction temp-erature over a wide range of ambient temperature, with a high degree of accuracy. Ry integrating the copper leads with the cold junctions, the thermocouple material itself is not connected to the input terminal of the measurement device M, thereby eliminating secondary errors.
The circuit is a bridge for the Thermistor pair Tl, T2 and the proper corresponding resistors, as qiven in the table herein, have been selected by computer read-out to give a nearly smooth temperature-resistance curve. The pair of Thermistors Tl, T2 are preferably selected to be ~0~ 7 as nearly identical as possible, and the resistors should be selected to be within 2~ and preferably within 1~, of the values listed in the table on page 6.
Referring now to Figures l to 3, the module has a body 6 with a major cover 7 and a minor cover 8 adapted to be retained in position on the body 6 by metal screws 9 inserted in holes 10 and engaged in nuts 11. At one end of the body 6 there are provided two input sockets 12, 13 corresponding respectively to terminals 1 an~ 2 (see Figure 4) and respectively connected to the input conductors la and 2a. At the other end of the body ~ are provided screw terminals 3, 4 corresponding to output terminals 3 and 4 of Figure 4. Intermediately, the body receives a removable board 14 of insulating material on which are mounted the resistors Rl, ~2~ R5, ~6 and D, and the variable resistor P. A matched pair of Thermistors Tl, T2 can be used for different circuits and comhinations of metals by modular substitution of the resistor parts of the circuit by plugging in alternative units. In the board 14 there is provided a well 15 to accommodate the battery B retained by a spring contact 16. On the outer face of the body 6 there is provided a rotatahly removable cover 17 for the battery B, and this also serves as a supply switch and may have, for example, three positions indicated by an index 18 and giving conditions of "off", "open", and "on". The switch is not shown in the circuit of Figure 4, and it could be omitted and the unit left energised for the normal running life of the cell, say 2000 hours or more. It would be included in the circuit of Figure 4 in the connection of either ~ole of the Battery B.
10~
The device may be placed in the enerqised state and then encapsulated, being intended to be discarded after the useful life of the battery has terminated.
.~ battery test light 19 can be utilised by inserting a point such as a pencil point through an aperture of the cover 17 to place the test light in parallel with the battery to show the state of the battery.
The input sockets 12 and 13 can serve as the sockets of a conventional male-female plug connection, e.g. as in the form shown in Figure 1 wherein the sockets are adapte~
to receive the pins 21, 22 of a conventional male thermo-couple plug 23.
The sockets 12 and 13 can also receive removable pins 24 and 25, as shown in Figure 2, such that the module has then male pins 24 and 25 for insertion into the sockets of a conventional female thermocouple jack 26. The pins 2~ and 25 are advantageously of different diameters, and of different metals.
In a practical construction, the module body 6 could 20 have dimensions as follows:
Length ..................... 3 inches Width ...................... 1 inch Thickness .................. ~ inch Weight, with battery, approx. 2 oz.
The entire cold junction module can plug into any conventional thermocouple panel board or male quick-disconnect, or female quick disconnect with the use of pins 24 and 25.
It can be made highly stable, i.e. with a stability better than +- 1C at any temperature over a range of + 10C to + 50C. Its output terminals can be connected to meters, records, or potentiometers with ordinary copper 'eads~
9;~37 The small "button" type battery, e.g. Mallory PX625, can give over 2500 hours of continuous operation. The circuit components do not require any warm-up time.
The module may advantageously be colour-coded in standard manner fox the pair of metal thermocouple elements it is designed to operate with.
. ~Ofà9;~3'7 ~ nother object of the invention is to provide an extremely versatile cold junction compensator which is no longer than a conventional quick-disconnect thermocouple connector and which is readily portable.
A still further object of the invention is to provide a cold junction compensator which can operate on a replace-able button-type self-contained mercury battery.
SU~RY OF THE INVENTIOM
~ccording to the present invention, a cold junction compensator comprises:-ti) a first input connector for connection to a first element of a sensing thermocouple, said first connector being made of one material of a thermo-couple junction;
(ii) a second input connector for connection to a second element of said sensing thermocouple, said .
second connector being made of said one material of a thermocouple junction;
(iii) a first conductor forming a thermocouple junction with said first connector;
(iv) a second conductor forming a thermocouple junction with said second connector;
(v) first and second output terminals;
(vi) an electrical connection between said first conductor and said first output terminal;
(vii) a voltage generator circuit between said second conductor and said second output terminal, said generating circuit being constructed such that, over a range of temperature, the voltage generated at any temperature is equal an~ opposite to the .. . .
10f;9~3'7 voltage differential generated by said thermo-couple junction~ at that temperature.
In a preferred form, the voltage generating circuit is a ~?heatstone bridge circuit including a supply battery, one arm including resistance elements whose value varies with variation of temperature, such as for exanple Thermistors.
Conveniently, the compensator is incorporated in a module in which the input connectors form or are incorporated in plugs or sockets for use respectively with a conventional female or male plug connector thermo-couple unit.
An important advantage may be gained in the invention by computer selection of resistors for the bridge circuit, to match the characteristics of a closely-matched pair of Thermistors which have the same or approxi-mately the same temperature-resistance curve, say within .2C interchangeability, or most preferably within .1C
interchangeability.
A further advantageous feature of the invention is the possibility of substitution of the resistor portions of the circuit, e.g by plugging in alternative units, to permit the same matched pair of Thermistors to be used for different circuits and metal-metal combinations.
A still further advantageous feature of the invention is the po~sibility of substitution of the Thermistor portion of the circuit, as well as or alternatively to the substitu-tion of the resistor portion of the circuit.
The power supply for the voltage generating circuit is conveniently obtained from a primarv hattery, and at lOfi:9;~3~7 least the battery and circuit may be encapsulated.
Alternatively, switch means may be included in the battery circuit.
The above and other ohjects, features and advantages will be apparent from the following descrip-tion of an embodiment of cold junction compensator with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAI.A~INGS
Figure 1 is a perspective elevation sho~ing a cold-junction compensator module with sockets adapted to receive the pins of a male connector;
Figure 2 is a perspective elevation showing a compensator module arranged having male pins for engagement in a female connector;
Figure 3 is a perspective view of a compensator module, with cover portions shown separated, and with pins omitted;
Figure 4 is a circuit program of the internal compon-ents and connections of the compensator of any of Figures 1, 2 and 3.
Dl~:SCRIPTION OF TH~ PRE~P~P~F.D ~3~C)DIMENT
Referring firstly to Figure 4, the unit has terminals 1 and 2 for receiving the input from a sensing thermocouple TH. Conductors la and 2a are both made of the sa~e thermo-couple alloy, and conductors lb and 2_ are both made of copper. Conductor 2a connects terminal 2 to a thermocouple junction J6' and conductor 2_ connects ~unction J~ directly to an output terminal 3 of a pair of output terminals 3, 4 connected to a measuring instrument or recorder ~. Conductor la connects terminal 1 to a thermocouple junction J~, and 10~
conductor lb connects junction J5 to a bridge circuit.
Conductor 4b, of copper, connects the bridge circuit to output terminal 4. Thermocouple junctions J5 and J~ are formed between the thermocouple alloy conductors la and 2a and the copper conductors l_ and 2_.
One arm of the hridge is constituted by resistors R2, R5 and variable resistor P in series, and the other arm of the bridge is constituted by two Thermistors Tl and T2 and shunt resistor D. ~ resistor ~6 is connected centrally across the bridge, and provides an output to conductors l and 4b. A battery B is connected in series with resistor Rl to the ends of the bridge.
Values of the resistors Rl, R2~ R5, R6, and D are shown in the following takle for various thermocouple pairs:
~ . .
S~ a~
a) ~ ~ , ~ ;r Q~ ~ u~~1 O O r-i~D ~ ~1 ~) ~
, . .. ___ __ a~ ~ ~ ~ . ' ~ ~ ~ ~ ~ O ~D ' C~ ~ U~00 ~ O
'~ ~
r- , ~ ~ ~ .Y~ O ~
.,1 ,1 0 O ~er ~ In r-l 1 a~ ~ r~
. ~ _ ___.
_~ .Y
~9 ~
~ a) ~ ~ ~ ~r co O ~j I~ D ~
u~
\V
~ ,y O ~r 1~ U~ U~~-1 In 5 O ~ ~ *
$
u~ ~ ~ In ~
_ . , I
l(J~ 37 Thermistors Tl and T2 = (e.g. YSl A4031 lOk @ 25C, or Y~l 44006) or any equivalent Thermistor pair having the same temperature or resistance characteristics.
B is a single cell battery, such as a "Mallory" PK625. P
is a variable resistor - 50 ohms.
The system incorporates two temperature sensitive elements ~Thermistors) which are thermally integrated ~ith the cold junctions 5 and 6. The circuit is energized from the battery B. The output voltage across register R6 is proportional to the unbalance created between a pre-set equivalent electronic reference temperature and the temperature of a hot junction. In this syste~, the reference temperature ~C may be chosen.
Since the cold junctions are subjected to ambient temperature, a thermally generated voltage is produced therein. This voltage would appear as an error voltage unless compensated for. This is accomplished by auto-matically injecting into the circuit an equal and opposite voltage. This cancels the error voltage and maintains the electrical equivalent of a static refere~ce junction temp-erature over a wide range of ambient temperature, with a high degree of accuracy. Ry integrating the copper leads with the cold junctions, the thermocouple material itself is not connected to the input terminal of the measurement device M, thereby eliminating secondary errors.
The circuit is a bridge for the Thermistor pair Tl, T2 and the proper corresponding resistors, as qiven in the table herein, have been selected by computer read-out to give a nearly smooth temperature-resistance curve. The pair of Thermistors Tl, T2 are preferably selected to be ~0~ 7 as nearly identical as possible, and the resistors should be selected to be within 2~ and preferably within 1~, of the values listed in the table on page 6.
Referring now to Figures l to 3, the module has a body 6 with a major cover 7 and a minor cover 8 adapted to be retained in position on the body 6 by metal screws 9 inserted in holes 10 and engaged in nuts 11. At one end of the body 6 there are provided two input sockets 12, 13 corresponding respectively to terminals 1 an~ 2 (see Figure 4) and respectively connected to the input conductors la and 2a. At the other end of the body ~ are provided screw terminals 3, 4 corresponding to output terminals 3 and 4 of Figure 4. Intermediately, the body receives a removable board 14 of insulating material on which are mounted the resistors Rl, ~2~ R5, ~6 and D, and the variable resistor P. A matched pair of Thermistors Tl, T2 can be used for different circuits and comhinations of metals by modular substitution of the resistor parts of the circuit by plugging in alternative units. In the board 14 there is provided a well 15 to accommodate the battery B retained by a spring contact 16. On the outer face of the body 6 there is provided a rotatahly removable cover 17 for the battery B, and this also serves as a supply switch and may have, for example, three positions indicated by an index 18 and giving conditions of "off", "open", and "on". The switch is not shown in the circuit of Figure 4, and it could be omitted and the unit left energised for the normal running life of the cell, say 2000 hours or more. It would be included in the circuit of Figure 4 in the connection of either ~ole of the Battery B.
10~
The device may be placed in the enerqised state and then encapsulated, being intended to be discarded after the useful life of the battery has terminated.
.~ battery test light 19 can be utilised by inserting a point such as a pencil point through an aperture of the cover 17 to place the test light in parallel with the battery to show the state of the battery.
The input sockets 12 and 13 can serve as the sockets of a conventional male-female plug connection, e.g. as in the form shown in Figure 1 wherein the sockets are adapte~
to receive the pins 21, 22 of a conventional male thermo-couple plug 23.
The sockets 12 and 13 can also receive removable pins 24 and 25, as shown in Figure 2, such that the module has then male pins 24 and 25 for insertion into the sockets of a conventional female thermocouple jack 26. The pins 2~ and 25 are advantageously of different diameters, and of different metals.
In a practical construction, the module body 6 could 20 have dimensions as follows:
Length ..................... 3 inches Width ...................... 1 inch Thickness .................. ~ inch Weight, with battery, approx. 2 oz.
The entire cold junction module can plug into any conventional thermocouple panel board or male quick-disconnect, or female quick disconnect with the use of pins 24 and 25.
It can be made highly stable, i.e. with a stability better than +- 1C at any temperature over a range of + 10C to + 50C. Its output terminals can be connected to meters, records, or potentiometers with ordinary copper 'eads~
9;~37 The small "button" type battery, e.g. Mallory PX625, can give over 2500 hours of continuous operation. The circuit components do not require any warm-up time.
The module may advantageously be colour-coded in standard manner fox the pair of metal thermocouple elements it is designed to operate with.
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A cold junction compensator comprising:
(i) a first input connector for connection to a first element of a sensing thermocouple, said first connector being made of one material of a thermocouple junction;
(ii) a second input connector for connection to a second element of said sensing thermocouple, said second connector being made of said one material of a thermocouple junction;
(iii) a first conductor forming a thermocouple junction with said first connector;
(iv) a second conductor forming a thermocouple junction with said second connector;
(v) first and second output terminals;
(vi) an electrical connection between said first conductor and said first output terminal;
(vii) a voltage generator circuit between said second conductor and said second output terminal, said generating circuit being a Wheatstone bridge circuit including a supply battery, two arms of the bridge being constituted by Thermistors, such that over a range of temperature, the voltage generated at any temperature, is equal and opposite to the voltage differential generated by said thermocouple junctions at that temperature.
(i) a first input connector for connection to a first element of a sensing thermocouple, said first connector being made of one material of a thermocouple junction;
(ii) a second input connector for connection to a second element of said sensing thermocouple, said second connector being made of said one material of a thermocouple junction;
(iii) a first conductor forming a thermocouple junction with said first connector;
(iv) a second conductor forming a thermocouple junction with said second connector;
(v) first and second output terminals;
(vi) an electrical connection between said first conductor and said first output terminal;
(vii) a voltage generator circuit between said second conductor and said second output terminal, said generating circuit being a Wheatstone bridge circuit including a supply battery, two arms of the bridge being constituted by Thermistors, such that over a range of temperature, the voltage generated at any temperature, is equal and opposite to the voltage differential generated by said thermocouple junctions at that temperature.
2. A cold junction compensator, as claimed in claim 1, wherein said first and second input connectors are sockets adapted to receive pins of a thermocouple plug unit.
3. A cold junction compensator, as claimed in claim 2, including plug means disposed in said sockets for engagement in a thermocouple socket unit.
4. A cold function compensator module comprising:
(a) a body including removably attachable cover means, and (b) a cold function compensator as claimed in claim 1 mounted in said body with said first and second input connectors accessible at the exterior of said body.
(a) a body including removably attachable cover means, and (b) a cold function compensator as claimed in claim 1 mounted in said body with said first and second input connectors accessible at the exterior of said body.
5. A cold function compensator module comprising:
(a) a body including a cover, and (b) a cold junction compensator as claimed in claim 1 mounted in said body with said first and second input connectors accessible at the exterior of said body, said cover being re-movable to provide access to said first and second output terminals.
(a) a body including a cover, and (b) a cold junction compensator as claimed in claim 1 mounted in said body with said first and second input connectors accessible at the exterior of said body, said cover being re-movable to provide access to said first and second output terminals.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1047875A GB1531423A (en) | 1975-03-13 | 1975-03-13 | Cold junction compensator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1069337A true CA1069337A (en) | 1980-01-08 |
Family
ID=9968600
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA247,822A Expired CA1069337A (en) | 1975-03-13 | 1976-03-12 | Cold junction thermocouple compensator |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS51117084A (en) |
| CA (1) | CA1069337A (en) |
| DE (1) | DE2610468A1 (en) |
| GB (1) | GB1531423A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59104213U (en) * | 1982-12-27 | 1984-07-13 | オムロン株式会社 | air conditioner |
| JPH0632591Y2 (en) * | 1987-03-31 | 1994-08-24 | オムロン株式会社 | Temperature measuring device |
| DE3830415A1 (en) * | 1988-09-07 | 1990-03-15 | Sachs Ersa Kg | TERMINAL COMPENSATION MEASUREMENT FOR TEMPERATURE CONTROLLERS AND MEASURING DEVICES |
| DE4114921A1 (en) * | 1991-05-07 | 1992-11-12 | Ahlborn Mess Und Regelungstech | Electrical plug connector with multiple pins - has EEPROM memory that can be programmed with data defining specific configuration being used |
| GB0220048D0 (en) * | 2002-08-29 | 2002-10-09 | Melexis Nv | Infrared sensing device |
| DE102010038104B4 (en) | 2010-10-11 | 2021-09-09 | Ipetronik Gmbh & Co. Kg | Universal thermal socket |
| CN105911412B (en) * | 2016-04-16 | 2023-03-31 | 浙江德广科技有限公司 | Network cable test hunting device |
-
1975
- 1975-03-13 GB GB1047875A patent/GB1531423A/en not_active Expired
-
1976
- 1976-03-12 CA CA247,822A patent/CA1069337A/en not_active Expired
- 1976-03-12 DE DE19762610468 patent/DE2610468A1/en active Pending
- 1976-03-13 JP JP2761776A patent/JPS51117084A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS51117084A (en) | 1976-10-14 |
| DE2610468A1 (en) | 1976-09-30 |
| GB1531423A (en) | 1978-11-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4133700A (en) | Cold junction thermocouple compensator | |
| EP0686835B1 (en) | Compact thermocouple connector | |
| CN1192223C (en) | Calibrated isothermal assembly for thermocouple thermometer | |
| US2753714A (en) | Electric thermometer | |
| US4776706A (en) | Universal connector and compensating terminal apparatus for temperature responsive instruments | |
| CN109738485B (en) | Device and method for measuring heat conductivity coefficient of solid material | |
| CA1069337A (en) | Cold junction thermocouple compensator | |
| US20110006754A1 (en) | Current measurement apparatus with shunt resistor and heat sink | |
| CN2234085Y (en) | Thermocouple cold junction temperature compensation circuit | |
| EP1510801B1 (en) | Method, system and apparatus for measuring temperature with cold junction compensation | |
| US7188996B2 (en) | Expiration indicator | |
| US5163755A (en) | Temperature regulator | |
| US20020048309A1 (en) | Method and apparatus for testing a temperature sensor | |
| US5336990A (en) | Electrical test shunt having dual contact point mating terminals | |
| US3192770A (en) | Multi-point measuring apparatus | |
| US20020128791A1 (en) | Integrated circuit of an electronic thermometer | |
| Dudarev et al. | New bridge temperature sensor for superconducting magnets and other cryogenic applications | |
| CN211829098U (en) | Battery circuit of electronic equipment and electronic equipment | |
| Ascroft | Developments in coaxial power standards at NPL | |
| JPS60501721A (en) | Temperature measurement probe | |
| FR2382107A1 (en) | Temp. monitor system for electric battery - has probes to measure temp. differential between battery and environment | |
| US3625059A (en) | Remote cryogenic temperature indicating system | |
| GB2032109A (en) | Measuring temperature and thermal flux | |
| RU2095767C1 (en) | Portable thermometer | |
| Channel | Thermometers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |