THERMOCOUPLES

  1. Working principle
  2. Measuring methods
  3. Thermocouples construction
  4. Traditional insulation thermocouples
  5. Mineral insulation thermocouples
  6. Main causes of errors in measurement with thermocouples
  7. Reference tables
  8. Tolerances and appliances limits

 

A thermocouple comprises an electrical circuit formed by two metal conductors of different metals soldered together at the ends. When there is a difference in temperature between the two joints, due to the Seebeck effect, a loop of current is generated and then, if one of the two joints is opened, an electromotive force (emf).
The polarization and intensity of the electromotive force depends solely on the type of metals used and the temperature to which the joints are subjected.
The joint exposed to the temperature to be measured is called the hot junction or the measuring junction while the joint between the thermocouple conductors and the measuring circuit is called the cold junction or the reference junction.
To measure a temperature with a thermocouple the reference junction must be at a given temperature (normally 0°) so that the emf generated depends solely on the temperature of the measuring junction. The type of thermocouple depends on the materials comprising the conductors which can be summarized as follows:

 

Type
Temperature limits (°C)
Description
Symbol
Materials
S
Pt10%Rh - Pt
-50 / 1760
Thermocouples composed of noble metals (Platinum and Rhodium) enable very precise measurements to be obtained. Especially resistant at high temperatures, it is generally used in oxidizing atmospheres. It is not really recommended in reducing atmospheres or those containing metal gases.
R
Pt13%Rh - Pt
-50 / 1760
Like the "S" type thermocouple but with different percentages of the two metals.
B
Pt30%Rh - Pt6%Rh
0 / 1820
Thermocouple composed of noble metals which, due to a greater quantity of Rhodium than the "S" and "R" types, is more resistant at high temperatures and to mechanical stress.
E
Cr - Co
-270 / 1000
Thermocouple with high thermoelectrical power which combines the positive pole of the "K" type thermocouple and the negative pole of the "J" type thermocouple.
Particularly indicated in oxidizing atmospheres
J
Fe - Co
-210 / 1200
Thermocouple comprising an iron positive pole and a constantan (copper-nickel alloy) negative pole. Indicated for measuring medium temperatures in reducing atmospheres and with the presence of hydrogen and carbon.
The presence of iron jeopardizes its working properly in oxidizing atmospheres
K
Cr - Al
-270 / 1370
Thermocouple composed of alloys containing nickel. It is suitable for measuring high temperatures in oxidizing atmospheres. Not to be used in reducing atmospheres.
T
Cu - Co
-270 / 400
Thermocouple which permits accurate measurements at low temperatures in oxidizing and reducing atmospheres.
N
Nicrosil - Nisil
-270 / 400 (1)
0 / 1300 (2)
Thermocouple for high temperatures similar to type "K" but with less hysteresis.
W3
W3%Re- W25%Re
0 / 2310
Thermocouple for extremely high temperatures comprising a Tungsten positive pole containing 3% rhenium and a Tungsten negative pole containing 25% rhenium.
Particularly resistant in reducing atmospheres and in the presence of hydrogen or other inert gases.
Not to be used in air or oxidizing atmospheres.
W5
W5%Re - W26%Re
0 / 2310
Thermocouple very similar to W3 but with a greater percentage of rhenium which increases its mechanical resistance. Other characteristics are identical to those of the W3 thermocouple.

 

(1) Thermocouple with 0.32 mm diameter wires
(2) Thermocouple with 1.63 mm diameter wires

 

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The methods for carrying out measurements with thermocouples can generally be divided into two types.

The first, as shown in figure No. 1, is generally used in industrial fields where extreme precision is not necessary

 

 

In this case the thermocouple is connected directly (fig. 1a) to the measuring device using compensated or extension cables (fig. 1b).
In this case the compensation of the reference junction is carried out directly by the measuring device which, measuring the junction temperature with other types of sensors, electronically modifies the thermocouple signal so that it is only dependent on the temperature of the measuring junction and thus the temperature to be measured.

The second type enables highly accurate measurements to be obtained and for this reason is used almost exclusively in laboratory applications.

 

 

In this case the temperature of the reference junction is maintained at a given and constant temperature (normally the melting point of ice 0°C) through manual or automatic procedures in order to compensate the electromotive force measured by the measuring device with that corresponding to the measuring junction.

 

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As in the case of resistance thermometers, there are also basically two construction types of thermocouples:
with traditional insulation and with mineral insulation.

The following table shows the main characteristics of the two construction types

 

Response speed
Elertrical Insulation
Resistance to vibrations
Resistance to pressure
Traditional Insulation
Sufficient
Good
Sufficient
Good
Mineral Insulation (MgO)
Excellent
Good
Excellent
Excellent

 

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Traditional insulation thermocouples comprise:

1- Measuring junction
The measuring junction or hot junction is the area in which the two conductors of the thermocouple are joined together; since its dimensions are small, we can consider the measurement carried out with the thermocouples to be punctiform. This junction must be created in such a way that there is no mechanical stress on the two conductors (especially as regards thermocouples made of noble metals) as, once at temperature, this would jeopardize the correct functioning of the thermocouple.

2- Thermocouple wires
The wires of the thermocouple must be of appropriate dimensions for the conditions of use; it is possible to insert two or more thermocouples into the same probe.

3- Ceramic insulators
Ceramic insulators are used to keep the thermocouple wires insulated along the entire length of the probe both from each other and the external sheath.

4- Protective sheath
The protective sheath is designed to protect the thermocouple wires. Since it is in contact with the process, it is important that it is made of the right material and has the right dimensions.
The protective sheath is normally made of metal however it can be made of ceramic in the case of very high temperatures. In certain conditions is it advisable to cover the sheath with a further protective casing (thermowell).

5- Connection head
The connection head contains the terminal board made of insulating material (normally ceramic) which permits the electrical connection of the thermocouple. Depending on the conditions of use explosionproof casing may be used.
A 4-20mA converter can be installed instead of the terminal board.

 

In traditional insulation thermocouples the limits to the use of the different thermocouples is determined not only by the type of sheath but also by the dimensions of the thermocouple wires as indicated in the table below:

 

TYPE
CONDITIONS
WIRE DIAMETER (mm)
3
1,5
1,3
0,8
0,5
0,25

J

Bare wires

650
480
480
425
340
310

Sheated wires

760
590
450
480
370
370

K/N

Bare wires

1.090
925
925
870
760
700

Sheated wires

1.260
1.090
1.090
980
870
815

T

Bare wires

315
315
260
200
200
200

Sheated wires

370
370
315
260
200
200

E

Bare wires

760
590
590
480
370
370

Sheated wires

870
650
650
540
425
425

S/R

Bare wires

1.540
1.480
1.320

Sheated wires

B

Bare wires

1.700

Sheated wires

Temperature limits in °C

 

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This particular construction type enables the production of high performance thermocouples with excellent mechanical characteristics. The made construction characteristics can be summarized as follows:
- the possibility of producing extremely small thermocouples (from 0.5mm diameter)
- the possibility of bending the sheath with a very sharp bending radius
- the considerable increase in the average life of the thermocouple
- the possibility of producing very long thermocouples

1- Measuring junction
Special techniques are used to create the joint between the two conductors forming the thermocouple inside the mineral oxide insulation cable which is then closed. The measuring junction can be insulated, grounded or exposed (see table).

2- Thermocouple wires
Inside the mineral oxide insulation cable there can be two, four or six wires; the thermocouple can thus be simple, double or triple.

3- Sheath with mineral insulation
This comprises a metal sheath containing the conductors which are insulated from each other and from the sheath itself by extremely pure and highly compressed metal oxides; standard insulation uses magnesium oxide, MgO.

4- Connection head
The connection head contains the terminal board made of insulating material (normally ceramic) which permits the electrical connection of the thermocouple. Depending on the conditions of use explosionproof casing may be used. A 4-20mA converter can be installed instead of the terminal board.

 

There are three types of measuring junction for mineral insulation thermocouples; the choice depends on the conditions of use of the thermocouple.

 

 

A- Exposed hot junction
Characterized by very a short response time as it is in direct contact with the environment in which the temperature must be measured; however it is not recommended for use in corrosive environments.

B- Grounded hot junction
The measuring junction is an integral part of the protective sheath and consequently the response time is quite short. This junction conforms to the ASTM-E-235 standard.
It is recommended where there is high pressure (up to 3500Kg/cm2).

C- Insulated hot junction
The hot junction is completely insulated from the protective sheath and is, therefore, particularly indicated in cases where parasitic emf could affect the measurements. This junction conforms to the ASTM-E-235 standard.

 

 

The following chart shows the time it takes a mineral insulation thermocouple to reach 63.2% of the thermal head measured in water with a speed of 0.4m/s

 

 

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The main causes of errors which can occur while measuring the temperature with thermocouples are the following:
- Connection of thermocouple to the measuring device with an unsuitable cable
- Inversion of polarity in the connections
- Parasitic emf
- Incorrect compensation of the reference junction

All the connections between the thermocouples and the measuring devices must be carried out with suitable compensated cables. There are compensated cables for each type of thermocouple, the choice of type of insulation and dimensions depends solely on the conditions of use (see section on cables).

All compensation and/or extension cables for thermocouples have a color identifying both the type of thermocouple and its polarity. It is, therefore, important to take care not to invert the polarities in any connections.
It is, however, good practice to make as few junctions as possible in connections between thermocouples and measuring instruments and to use the special devices with compensated contacts which prevent polarity inversion.

When using thermocouples with grounded measuring junctions, parasitic emf may be introduced from the thermocouple to the measuring device and, since the thermocouple signal is in mV, it may easily be disturbed or altered.
It is, therefore, advisable to use thermocouples with insulated measuring junctions.

As stated previously measuring with thermocouples requires the compensation of the reference junction; it is important that this be carried out correctly by the measuring device.

 

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TERMOCOUPLE TYPE "B" ( PtRh30% vs. PtRh6% ) ACC. TO EN 60584-1 ( ITS90 )
°C
0
10
20
30
40
50
60
70
80
90
°C
FEM thermoelectric voltage in mV
0
0,000
-0,002
-0,003
-0,002
0,000
0,002
0,006
0,011
0,017
0,025
0
100
0,033
0,043
0,053
0,065
0,078
0,092
0,107
0,123
0,141
0,159
100
200
0,178
0,199
0,220
0,243
0,267
0,291
0,317
0,344
0,372
0,401
200
300
0,431
0,462
0,494
0,527
0,561
0,596
0,632
0,669
0,707
0,746
300
400
0,787
0,828
0,870
0,913
0,957
1,002
1,048
1,095
1,143
1,192
400
500
1,242
1,293
1,344
1,397
1,451
1,505
1,561
1,617
1,675
1,733
500
600
1,792
1,852
1,913
1,975
2,037
2,101
2,165
2,230
2,296
2,363
600
700
2,431
2,499
2,569
2,639
2,710
2,782
2,854
2,928
3,002
3,078
700
800
3,154
3,230
3,308
3,386
3,466
3,546
3,626
3,708
3,790
3,873
800
900
3,957
4,041
4,127
4,213
4,299
4,387
4,475
4,564
4,653
4,743
900
1.000
4,834
4,926
5,018
5,111
5,205
5,299
5,394
5,489
5,585
5,682
1.000
1.100
5,780
5,878
5,976
6,075
6,175
6,276
6,377
6,478
6,580
6,683
1.100
1.200
6,786
6,890
6,995
7,100
7,205
7,311
7,417
7,524
7,632
7,740
1.200
1.300
7,848
7,957
8,066
8,176
8,286
8,397
8,508
8,620
8,731
8,844
1.300
1.400
8,956
9,069
9,182
9,296
9,410
9,524
9,639
9,735
9,868
9,984
1.400
1.500
10,099
10,215
10,331
10,447
10,563
10,679
10,796
10,913
11,029
11,146
1.500
1.600
11,263
11,380
11,497
11,614
11,731
11,848
11,965
12,082
12,199
12,316
1.600
1.700
12,433
12,549
12,666
12,782
12,898
13,014
13,130
13,246
13,361
13,476
1.700
1.800
13,591
13,706
13,820
1.800
0
10
20
30
40
50
60
70
80
90

Reference junction at 0°C

 

TERMOCOUPLE TYPE "E" ( Cr-Co ) ACC. TO EN 60584-1 ( ITS 90 )
°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
FEM thermoelectric voltage in mV
-200
-8,825
-9,063
-9,274
-9,455
-9,604
-9,718
-9,797
-9,835
-200
-100
-5,237
-5,681
-6,107
-6,516
-6,907
-7,279
-7,632
-7,963
-8,273
-8,561
-100
0
0,000
-0,582
-1,152
-1,709
-2,255
-2,787
-3,306
-3,381
-4,302
-4,777
0
°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
°C
0
10
20
30
40
50
60
70
80
90
°C
FEM thermoelectric voltage in mV
0
0,000
0,591
1,192
1,801
2,420
3,048
3,685
4,330
4,985
5,648
0
100
6,319
6,998
7,685
8,379
9,081
9,789
10,503
11,224
11,951
12,684
100
200
13,421
14,164
14,912
15,664
16,420
17,181
17,945
18,713
19,484
20,259
200
300
21,036
21,817
22,600
23,386
24,174
24,964
25,757
26,552
27,348
28,146
300
400
28,946
29,747
30,550
31,354
32,159
32,965
33,772
34,579
35,387
36,196
400
500
37,005
37,815
38,624
39,434
40,243
41,053
41,862
42,671
43,479
44,286
500
600
45,093
45,900
46,705
47,509
48,313
49,116
49,917
50,718
51,517
52,315
600
700
53,112
53,908
54,703
55,497
56,289
57,080
57,870
58,659
59,446
60,232
700
800
61,017
61,801
62,583
63,364
64,144
64,922
65,698
66,473
67,246
68,017
800
900
68,787
69,554
70,319
71,082
71,844
72,603
73,360
74,115
74,869
75,621
900
1.000
76,373
1.000
°C
0
10
20
30
40
50
60
70
80
90
°C
Reference junction at 0°C

 

TERMOCOUPLE TYPE "J" ( Fe-Co ) ACC. TO EN 60584-1 ( ITS 90 )

°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
FEM thermoelectric voltage in mV
-200
-7,890
-8,095
-200
-100
-4,633
-5,037
-5,426
-5,801
-6,159
-6,500
-6,821
-7,123
-7,403
-7,659
-100
0
0,000
-0,501
-0,995
-1,482
-1,961
-2,431
-2,893
-3,344
-3,786
-4,215
0
°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
°C
0
10
20
30
40
50
60
70
80
90
°C
FEM thermoelectric voltage in mV
0
0,000
0,507
1,019
1,537
2,059
2,585
3,116
3,650
4,187
4,726
0
100
5,269
5,814
6,360
6,909
7,459
8,010
8,562
9,115
9,669
10,224
100
200
10,779
11,334
11,889
12,445
13,000
13,555
14,110
14,665
15,219
15,773
200
300
16,327
16,881
17,434
17,986
18,538
19,090
19,642
20,194
20,745
21,297
300
400
21,848
22,400
22,952
23,504
24,057
24,610
25,164
25,720
26,276
26,834
400
500
27,393
27,953
28,516
29,080
29,647
30,216
30,788
31,362
31,939
32,519
500
600
33,102
33,689
34,279
34,873
35,470
36,071
36,675
37,284
37,896
38,512
600
700
39,132
39,755
40,382
41,012
41,645
42,281
42,919
43,559
44,203
44,848
700
800
45,494
46,141
46,786
47,431
48,074
48,715
49,353
49,989
50,622
51,251
800
900
51,877
52,500
53,119
53,735
54,347
54,956
55,561
56,164
56,763
57,360
900
1.000
57,953
58,545
59,134
59,721
60,307
60,890
61,473
62,054
62,634
63,214
1.000
1.100
63,792
64,370
64,948
65,525
66,102
66,679
67,255
67,831
68,406
68,980
1.100
1.200
69,553
1.200
°C
0
10
20
30
40
50
60
70
80
90
°C
Reference junction at 0°C

 

TERMOCOUPLE TYPE "K" ( Cr-Al ) ACC. TO EN 60584-1 ( ITS 90 )

°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
FEM thermoelectric voltage in mV
-200
-5,891
-6,035
-6,158
-6,262
-6,344
-6,404
-6,441
-6,458
-200
-100
-3,554
-3,852
-4,138
-4,411
-4,669
-4,913
-5,141
-5,354
-5,550
-5,730
-100
0
0,000
-0,392
-0,778
-1,156
-1,527
-1,889
-2,243
-2,587
-2,920
-3,243
0
°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
°C
0
10
20
30
40
50
60
70
80
90
°C
FEM thermoelectric voltage in mV
0
0,000
0,397
0,798
1,203
1,612
2,023
2,436
2,851
3,267
3,682
0
100
4,096
4,509
4,920
5,328
5,735
6,138
6,540
6,941
7,340
7,739
100
200
8,138
8,539
8,940
9,343
9,747
10,153
10,561
10,971
11,382
11,795
200
300
12,209
12,624
13,040
13,457
13,874
14,293
14,713
15,133
15,554
15,975
300
400
16,397
16,820
17,243
17,667
18,091
18,516
18,941
19,366
19,792
20,218
400
500
20,644
21,071
21,497
21,924
22,350
22,776
23,203
23,629
24,055
24,480
500
600
24,905
25,330
25,755
26,179
26,602
27,025
27,447
27,869
28,289
28,710
600
700
29,129
29,548
29,965
30,382
30,798
31,213
31,628
32,041
32,453
32,865
700
800
33,275
33,685
34,093
34,501
34,908
35,313
35,718
36,121
36,524
36,925
800
900
37,326
37,725
38,124
38,522
38,918
39,314
39,708
10,101
40,490
40,885
900
1.000
41,276
41,665
42,053
42,440
42,826
43,211
43,595
43,978
44,359
44,740
1.000
1.100
45,119
45,497
45,873
46,249
46,623
46,995
47,367
47,737
48,105
48,473
1.100
1.200
48,838
49,202
49,565
49,926
50,286
50,644
51,000
51,355
51,708
52,060
1.200
1.300
52,410
52,759
53,106
53,451
53,795
54,138
54,479
54,819
1.300
°C
0
10
20
30
40
50
60
70
80
90
°C
Reference junction at 0°C

 

TERMOCOUPLE TYPE "N" ( Nicrosil - Nisil ) ACC. EN 60584-1 ( ITS 90 )

°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
FEM thermoelectric voltage in mV
-200
-3,990
-4,083
-4,162
-4,226
-4,313
-4,336
-4,345
-200
-100
-2,407
-2,612
-2,808
-2,994
-3,171
-3,336
-3,491
-3,634
-3,766
-3,884
-100
0
0,000
-0,260
-0,518
-0,772
-1,023
-1,269
-1,509
-1,744
-1,972
-2,193
0
°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
°C
0
10
20
30
40
50
60
70
80
90
°C
FEM thermoelectric voltage in mV
0
0,000
0,261
0,525
0,793
1,065
1,340
1,619
1,902
2,189
2,480
0
100
2,774
3,072
3,374
3,680
3,989
4,302
4,618
4,937
5,259
5,585
100
200
5,913
6,245
6,579
6,916
7,255
7,597
7,941
8,288
8,637
8,988
200
300
9,341
9,696
10,054
10,413
10,774
11,136
11,501
11,867
12,234
12,603
300
400
12,974
13,346
13,719
14,094
14,469
14,846
15,225
15,604
15,984
16,366
400
500
16,748
17,131
17,515
17,900
18,286
18,672
19,059
19,447
19,835
20,224
500
600
20,613
21,003
21,393
21,784
22,175
22,566
22,958
23,350
23,742
24,134
600
700
24,527
24,919
25,312
25,705
26,098
26,491
26,883
27,276
27,669
28,062
700
800
28,455
28,847
29,239
29,632
30,024
30,416
30,807
31,199
31,590
31,981
800
900
32,371
32,761
33,151
33,541
33,930
34,319
34,707
35,095
35,482
35,869
900
1.000
36,256
36,641
37,027
37,411
37,795
38,179
38,562
38,944
39,326
39,706
1.000
1.100
40,087
40,466
40,845
41,223
41,600
41,976
42,352
42,727
43,101
43,474
1.100
1.200
43,846
44,218
44,588
44,958
45,326
45,694
46,606
46,425
46,789
47,152
1.200
1.300
47,513
1.300
°C
0
10
20
30
40
50
60
70
80
90
°C
Reference junction at 0°C

 

TERMOCOUPLE TYPE "R" ( PtRh13% - Pt ) ACC. TO EN 60584-1 ( ITS 90 )

°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
FEM thermoelectric voltage in mV
0
0,000
-0,051
-0,100
-0,145
-0,188
-0,226
0
°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
°C
0
10
20
30
40
50
60
70
80
90
°C
FEM thermoelectric voltage in mV
0
0,000
0,054
0,111
0,171
0,232
0,296
0,363
0,431
0,501
0,573
0
100
0,647
0,723
0,800
0,879
0,959
1,041
1,124
1,208
1,294
1,381
100
200
1,469
1,558
1,648
1,739
1,831
1,923
2,017
2,112
2,207
2,304
200
300
2,401
2,498
2,597
2,696
2,796
2,896
2,997
3,099
3,201
3,304
300
400
3,408
3,512
3,616
3,721
3,827
3,933
4,040
4,147
4,255
4,363
400
500
4,471
4,580
4,690
4,800
4,910
5,021
5,133
5,245
5,357
5,470
500
600
5,583
5,697
5,812
5,926
6,041
6,157
6,237
6,390
6,507
6,625
600
700
6,743
6,861
6,980
7,100
7,220
7,340
7,461
7,583
7,705
7,827
700
800
7,950
8,073
8,197
8,321
8,446
8,571
8,697
8,823
8,950
9,077
800
900
9,205
9,333
9,461
9,590
9,720
9,850
9,980
10,111
10,242
10,374
900
1.000
10,506
10,638
10,771
10,905
11,039
11,173
11,307
11,442
11,578
11,714
1.000
1.100
11,850
11,986
12,123
12,260
12,397
12,535
12,673
12,812
12,950
13,089
1.100
1.200
13,228
13,367
13,507
13,646
13,786
13,926
14,066
14,207
14,347
14,488
1.200
1.300
14,629
14,770
14,911
15,052
15,193
15,334
15,475
15,616
15,758
15,899
1.300
1.400
16,040
16,181
16,323
16,464
16,605
16,746
16,887
17,028
17,169
17,310
1.400
1.500
17,451
17,591
17,732
17,872
18,012
18,152
18,292
18,431
18,571
18,710
1.500
1.600
18,849
18,988
19,126
19,264
19,402
19,540
19,677
19,814
19,951
20,087
1.600
1.700
20,222
20,356
20,488
20,620
20,749
20,877
21,003
1.700
°C
0
10
20
30
40
50
60
70
80
90
°C
Reference junction at 0°C

 

TERMOCOUPLE TYPE "S" ( PtRh10% - Pt ) ACC. TO EN 60584-1 ( ITS 90 )

°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
FEM thermoelectric voltage in mV
0
0,000
-0,053
-0,103
-0,150
-0,194
-0,236
0
°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
°C
0
10
20
30
40
50
60
70
80
90
°C
FEM thermoelectric voltage in mV
0
0,000
0,055
0,113
0,173
0,235
0,299
0,365
0,433
0,502
0,573
0
100
0,646
0,720
0,795
0,872
0,950
1,029
1,110
1,191
1,273
1,357
100
200
1,441
1,526
1,612
1,698
1,786
1,874
1,962
2,052
2,141
2,232
200
300
2,323
2,415
2,507
2,599
2,692
2,786
2,880
2,974
3,096
3,164
300
400
3,259
3,355
3,451
3,548
3,645
3,742
3,840
3,938
4,036
3,134
400
500
4,233
4,332
4,432
4,532
4,632
4,732
4,833
4,934
5,035
5,137
500
600
5,239
5,341
5,443
5,546
5,659
5,753
5,857
5,961
6,065
6,170
600
700
6,275
6,381
6,486
6,593
6,699
6,806
6,913
7,020
7,128
7,236
700
800
7,345
7,454
7,563
7,673
7,783
7,893
8,003
8,114
8,226
8,337
800
900
8,449
8,562
8,674
8,787
8,900
9,014
9,128
9,242
9,357
9,472
900
1.000
9,587
9,703
9,819
9,935
10,051
10,168
10,285
10,403
10,520
10,638
1.000
1.100
10,757
10,875
10,994
11,113
11,232
11,351
11,471
11,590
11,710
11,830
1.100
1.200
11,951
12,071
12,191
12,312
12,433
12,554
12,675
12,796
12,917
13,038
1.200
1.300
13,159
13,280
13,402
13,523
13,644
13,766
13,887
14,009
14,130
14,251
1.300
1.400
14,373
14,494
14,615
14,736
14,857
14,978
15,099
15,220
15,341
15,461
1.400
1.500
15,582
15,702
15,822
15,942
16,062
16,182
16,301
16,420
16,539
16,658
1.500
1.600
16,777
16,895
17,013
17,131
17,249
17,366
17,483
17,600
17,717
17,832
1.600
1.700
17,947
18,061
18,174
18,825
18,395
18,503
18,609
1.700
°C
0
10
20
30
40
50
60
70
80
90
°C
Reference junction at 0°C

 

TERMOCOUPLE TYPE "T" ( Cu-Co ) ACC. TO EN 60584-1 ( ITS 90 )

°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
FEM thermoelectric voltage in mV
-200
-5,603
-5,753
-5,888
-6,007
-6,105
-6,180
-6,232
-6,258
-200
-100
-3,379
-3,657
-3,923
-4,177
-4,419
-4,648
-4,865
-5,070
-5,261
-5,439
-100
0
0,000
-0,383
-0,757
-1,121
-1,475
-1,819
-2,153
-2,476
-2,788
-3,089
0
°C
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
°C
°C
0
10
20
30
40
50
60
70
80
90
°C
FEM thermoelectric voltage in mV
0
0,000
0,391
0,790
1,196
1,612
2,036
2,468
2,909
3,358
3,814
0
100
4,279
4,750
5,228
5,714
6,206
6,704
7,209
7,720
8,237
8,759
100
200
9,288
9,822
10,362
10,907
11,458
12,013
12,574
13,139
13,709
14,283
200
300
14,862
15,445
16,032
16,624
17,219
17,819
18,422
19,030
19,641
20,255
300
400
20,872
400
°C
0
10
20
30
40
50
60
70
80
90
°C
Reference junction at 0°C

 

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TYPE
JIS C 1602
ANSI MC 96.1
DIN 43710
EN 60584-2
Temp. range (°C)
Grade
Tolerance
(°C)
Temp.
range (°C)
Grade
Tolerance
(°C)
Temp. range (°C)
Tolerance (°C)
Temp.
range (°C)
Grade
Tolerance (°C)
B
+200+1700
0.5
± 4°C or
± 0.5%
+800+1700
STD
± 0.5%
-
-
+600+1700
2
± 0.0025*|t|
3
± 4°C or
± 0.005* |t|
R
0+1600
0.25
± 1.5°C or
± 0.25%
0+1450
STD
± 1,5°C or
± 0,25%
0+600
± 3°C
0-1600
1
± 1°C or
± [1+0.003 * (T-1100)]
°C
SPC
± 0,6°C or
± 0,1%
+600+1600
± 5°C
2
± 1,5°C or
±
0.0025* |t|
S
0+1600
0.25
± 1.5°C or
± 0.25%
0+1450
STD
± 1,5°C or
± 0,25%
0-600
± 3°C
0-1600
1
± 1°C or
± [1+0.003 * (T-1100)]°C
SPC
± 0,6°C or
± 0,1%
600-1600
± 5°C
2
± 1,5°C or
±
0.0025* |t|
K
0+1000
0.4
± 1.5°C or
± 0.4%
0+1250
STD
± 2.2°C or
± 0.75%
0+400
± 3°C
-40+1000
1
± 1,5°C or
±
0.004* |t|
400+1200
± 0.75°C
0+1200
0.75
± 2.5°C or
± 0.75%
SPC
± 1.1°C or
± 0.40%
-40+1200
2
± 2,5°C or
±
0.0075* |t|
-200-0
1.5
± 2.5°C or
± 1.5%
-200-0
STD
± 2.2°C or
± 2%
-200+40
3
± 2,5°C or
±
0.015* |t|
N
0+1000
0.25
± 1.5°C or
± 0.4%
0+1250
STD
± 2.2°C or
± 0.75%
-
-
-40+1000
1
± 1,5°C or
±
0.004* |t|
0+1200
0.75
± 2.5°C or
± 0.75%
SPC
± 1.1°C or
± 0.40%
-40+1200
2
± 2,5°C or
±
0.0075* |t|
-200-0
1.5
± 2.5°C or
± 1.5%
-200-0
STD
± 2.2°C or
± 2%
-200+40
3
± 2,5°C or
±
0.015* |t|
E
0+800
0.4
± 1.5°C or
± 0.4%
0+900
STD
± 1,7°C or ± 0.50%
-
-
-40-800
1
± 1,5°C or
±
0.004* |t|
0.75
± 2.5°C or
± 0.75%
SPC
± 1°C or
± 0.40%
-40-900
2
± 2,5°C or
±
0.0075* |t|
-200-0
1.5
± 2.5°C or
± 1.5%
-200-0
STD
± 1.7°C or
± 1%
-200-40
3
± 2,5°C or
±
0.015* |t|
J
0+750
0.4
± 1.5°C or
± 0.4%
0+750
STD
± 2.2°C or
± 0.75%
0.400
± 3°C
-40+750
1
± 1,5°C or
±
0.004* |t|
0.75
± 2.5°C or
± 0.75%
SPC
± 1.1°C or
± 0.4%
400+900
± 0.75°
2
± 2,5°C or
±
0.0075* |t|
T
0+350
0.4
± 0.5°C or
± 0.4%
0+350
STD
± 0.5°C or
± 0.4%
-200+400
± 3°C
-40+350
1
± 0,5°C or
±
0.004* |t|
0.75
± 1°C or
± 0.75%
SPC
± 1°C or
± 0.75%
2
± 1°C or
±
0.0075* |t|
-200-0
1.5
± 1°C or
± 1.5%
-200-0
STD
± 1°C or
± 1.5%
-200+40
3
± 1°C or
±
0.015* |t|

 

 

 

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