2848

f$ : 284% - 1986

Indian Standard

SPECIFICATION FOR INDUSTRTAL PLATINUM RESISTANCE THERMOMETER SENSORS

( First Revision )

Industrial Process Measurement and Control Sectional Committee, ETDC 67

Chairman

PROP J. K. Caounnua~ Jadavpur University, Calcutta

Members Refrescnting

SHRI ABHIJIT DE Sett and De, Calcutta SHRI A~ITAVA SENWPTA M. N. Dastur & Co Pvt Ltd, Calcutta

SEW ACHINTYA KUMER BISWAS ( Alternate ) SERI R. S. ARORA Dire;too; ,fteeneral of Supplies and Disposals,

SHRI G. BALARAM Indian Oil ?Zorporation, New Delhi SERI S. P. MATEUI~ (Alternate )

SERI G. BALASUBRAL~ANIAN Metallurgical and Engineering Consultants India Ltd, Ranchi

SHRI S. K. MlTuA (&tern&) SHRI K. R. BANERJEE Instrumentation Ltd, Kota

SHRI V. S. RA~ADAS ( Alternate ) SHRI J. K. CEATTERJEE Durgapur Steel Plant ( SAIL ), Durgapur SHRI D. P. GOEL Central Scientific Instruments Organization,

SHRI A. N. AQARWAL ( Alternate) Chandigarh

SHRI R. K. GOLIYA Udayraj and Sons, Bombay SERI P. C. G~LIYA ( Alternate )

SHRI G. L. KHANDUJA SHRI P. K. KRISIINAMURTHI

Electronics Corporation of India Ltd, Hyderbad lnstitute for Design of Electrical Measuring

Instruments, Bombay DR K. RA~ANI ( Alternate )

SHRI B. MUEHOPADHYA SHRI N. NARAYANA RAO

SHRI D. R. DHIMAN ( Alternate )

National Test House, Calcutta Controllerate of Inspection of Electronics,

Baogalore

( Continued on bag.4 2 )

0 Copyright 1987

BUREAU OF INDIAN STANDARDS

This publication is protected under the Indian CopVright Act ( XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act.

( Continued from page 1 )

Members

SHRI B. PYNE

SHRI A. GHOSH ( Alternate ) SHRI D. V. S. RAJU

SHRI M. ANAHD ( Alternate ) SHRI S. RAMANATHAN

SHRI V. S. RAMDASS SHRI RAMDAS KISSENDAS

SHRI S. K. SHARMA ( Alternate ) DR N. J. RAO

DR S. K. ACIARWAL (Alternate ) SHRI A. RAVI PRASAD

SHRI N. SRIRAMAN ( Alternate ) SHRI K. P. SHARMA

Cdlcutta Electric Supply Corporation ( I) Ltd, Calcutta

ELICO Pvt Ltd, Hyderabad

Indian Drugs & Pharmaceutics Ltd, Virbhadra, Rishikesh

Oil & Natural Gas Commission, Dehra Dun Indian Petrochemicals Corporation Ltd, Vadodara

Institute of Paper Technology, Saharanpur

Beacon Rotork Controls Ltd, Madras

Project and Development India Ltd, Bihar . . \ SHRI V. N. SRIVASTAVA ( Alternare )

SHRI M. S. SHETTY Tata Consulting Engineers, Bangalore SHRI K. G. SRINIVASAN ( Alternate)

SHRI CH. SURENDER Department of Atomic Energy, Bombay SHRI S. RAMAKRISHNAN ( Alternate j

SERI S. P.SURI National Physical Laboratory, New Delhi DR A. F. CHHAPGAR ( Alternate )

SHRI K. K. TANEJA Directorate General of Technical Development, New Delhi

SHRI MOHANJEET SIN~H ( Alternate ) SERI M. G. TOSHNIWAL Toshniwal Industries Pvt Ltd, Ajmer

SHRI S. C. MAHESHWARI ( Alternate ) SHRI 1. UDANI Procorn Engineers, Calcutta

S&I N. BANDYOPADHYAY ( Alternate ) - SHRI A. K. VERMA Engineers India Ltd, New Delhi

SEIRI R. RHANOT ( Alternate ) SHRI H. C. VERMA Associated Instrument Manufacturers ( I ) Pvt Ltd,

SHRI M. D. NAIR SHRI S. P. SAOHDEV,

Director ( Elec tech

New Delhi ( Alternate )

Director General, BIS ( Ex-officio Member ) )

Secsetav SHRI B. K. MAHATA

Joint Director ( Elec tech ), BIS

2

IS : 2848 - 1986

Indian Standard SPECIFICATION FOR INDUSTRIAL PLATINUM

RESISTANCE THERMOMETER

(First Revision)

0. FOREWORD

SENSORS

0.1 This Indian Standard ( First Revision ) was adopted by the Indian Standards Institution on 19 December 1986, after the draft finalizedby the Industrial Process Measurement and Control Sectional Committee had been approved by the Electrotechnical Division Council.

0.2 This standard was first published in 1965. This standard is revised to bring it in line with IEC Publication 751 and also to incorporate modified test methods and modifications in temperature/resistance relationship.

0.3 In the preparation of this revised standard, assistance has been deri- ved from IEC Publication 751-1983 Industrial Platinum Resistance Ther- mometer Sensors issued by International Electrotechnical Commission.

0.4 For the purpose of deciding, whether a particular requirement of this standard is complied with, the final value, observed or calculated, expres- sing the result of a test or analysis, shall be rounded off in accordance with IS : 2-1960*. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

1. SCOPE

1.1 This standard specifies requirements and test methods for industrial platinum resistance thermometer sensors whose electrical resistance is a defined function of temperature. The standard covers thermometers suitable for all or part of the temperature range -200°C to 850% with two tolerance classes. It is primarily concerned with sheathed elements suitable for immersion in the medium whose temperature is to be measured.

*Rules for rounding off numerical values ( reuised ).

3

IS : 2848 - 1986

2. TERMINOLOGY

2.0 For the purpose of this standard, the following definitions shall apply.

2.1 Ballast Resistor - A resistor, commonly having a negligible change of resistance with temperature, used in conjunction with the platinum resistor to bring the terminal resistance of the element within specified limits.

2.2 Fundamental Interval - The resistance change of a resistance element over the temperature range 0°C to 100°C.

2.3 Platinum Resistance Thermometer Sensor - A temperature- responsive device consisting of a sensing resistor within a protective sheath, internal connecting wires and external terminals to permit connection of electrical measurement devices. Mounting means or connection heads may be included. Typical constructions are shown in Fig. 1.

NOTE 1 - This resistance thermometer sensor is referred to as a thermometer in subsequent clauses of this standard.

NOTE 2 -- This definition excludes any separable pocket or well provided with the thermometer.

TERMINALS BLOCK RESISTOR SHEATH

FIG. 1 TYPICAL CONSTRUCTION OF RESISTANCE THERMOMETER SENSOR

2.4 Sealed Element - An element suitable for pressure tight immersion in a vessel without further protection.

2.5 Tolerance - For the purpose of this standard the tolerance of a resistance thermometer is the maximum allowable deviation expressed in degrees Celsius from the nominal resistance temperature relationship such as given in Table 1.

4

fS t 2sia - 1986

3. CONSTRUCTION

3.1 The conductor should be wound such that the method of supports shall avoid strain in the element both during fabrication and use.

3.2 The element shall be constructed so that no voltage is generated within them.

4. RESISTANCE CHARACTERISTICS

4.1 Temperature/Resistance Relationships - The temperaturelresi- stance relationships used in this standard are as follows:

i) for the range - 200°C to 0°C:

Rt = R, [ 1 + At + Btl + C ( t - 100 )ts ]

ii) for the range of 0°C to 850°C: Rt = R,, ( 1 + At + Bts )

For the quality of platinum commonly used for industrial resistance thermometers the values of the constants in these equations are:

3.908 02 x 10-3 “C-1 B^ : - 5.802 x IO-’ “C-a c= - 4.273 50 x 10-12 “C-4

For resistance thermometers satisfying the above relationship the temperature coefficient:

CI = 0.003 850 “C-l

alpha is defined as follows: R 100 - RO

a = 100 x R,- “C-1

where RI00 is resistance at IOO’C and R, resistance at 0°C.

These equations are listed as the basis for the temperature/resistance tables of this standard and are not intended to be used for calibration of individual thermometers.

Values of temperature in this standard are in the International Prac- tical Temperature Scale of 1968 ( IPTS-68 ).

NOTE - Unless specified by the manufacturer the resistance values defined by the above equations do not include resistance of the leads between the sensing resistor and terminations.

4.2 Resistance Values - Most thermometers are constructed to have a nominal resistance of lOOn or 1OQ at 0°C. The preferred value is lOO!Z The 1OQ is built with heavier wire for more reliable service above 600°C.

Values of resistance using the equations of 4.1 are given in Table 1.

5

TABLE 1 TEMPERATURE/RESISTANCE RELATIONSHIP g

EIPY-68 - -200 -150 -180 -170 -160 - 150 - 140 -130 -120

o\ -110 - 100

-90 -80 -70 -60 -50 -40 -30 -20 -10

0

tl

:!I 30 40 50 60 70

I_

. . ( Clause 4.3.1 )

g A.

R (0) = 100'00 A-2 a = 0’003 85O”C-1 0, I

5: 9 10

I “C

EIPT-6% z -

0 1 2 3 4 5 6 7 8

18.49 22.%0 27.08 31.32 35.53 39.71

21’94 21’51 26’23 25’80 30’47 30.05 34’69 34.27

43.87 48.00 52’11 56.19 60.25 64-30 68’33 72.33 76.33 80.3 i 84’27 88’22 92’16 96’09

100’00

22’37 26’65 30’90 35.11 39’30 43’45 47.59 51’70 55’7% 59.85 63.90 67.92 71’93 75.93 79’91 83.88 87’83 91.77 95.69 99.61

38’8% 43’04 47.1% 51.29 55’3%

5693::: 67.52 71.53 75’53 79’5 1 83’48 87’43 91.37 95’30 99’22

38’46 42’63 46.76 50’8% 54.97 59’04 63.09 67.12 71’13 75.13 79.11 83.0% 87’04 90.9% 94’91 98.83

21’0% 20’63 25.37 24’94 29’63 29.20 33 85 33’43 38 04 37’63 42.2 1 41’79 46’35 45’94 50’47 50’06 54’56 54’15 58’63 58’22 62.68 62.2% 66’72 66’31 70.73 70’33 74’73 74’33 78.72 78’32 82’69 82.29 86’64 86.25 90’59 90’19 94.52 94’12 9%,44 98.04

20’22 19’79 19.36 24.52 24 09 23.66 28’7% 2% 35 27.93 33.01 32.59 32’16 37’21 36.79 36.37 41’3% 40’96 40’55 45’52 45.11 44.70 49’64 49’23 48’82 53’74 53’33 52.92 57’82 57.41 57.00 61’87 61.47 61’06 65’91 65’51 65.11 69.93 69’13 73.93 z:: 73.13 77’92 77’52 77.13 81’89 81’50 81.10 85’85 85’46 85.06 89.80 89.40 89.0 1 93’73 93.34 92.95 97-65 97’26 96.87

102’34 102 73 103’12 106’24 106’63 107.02 110’12 110’51 110.90 113'99 114’38 114’77 117.85 118’24 118’62 121’70 122.09 122’47

1 125’54 125’92 126’31

18’93 18’49 23’23 22.80 27’50 27’0% 31’74 31’32 35’95 35.53 40’13 39.71 44’2% 43’87 48’41 48’00 52.52 52’11 56’60 56’ 19 60’66 60’25 64.70 64’30 68’73 63.33 72’73 72’33 76’73 76.33 80’70 80’31 84’67 84.27 88’62 88’22 92.55 92.16 96.48 96’09

103’51 103’90 107.40 107’79

-200 - 190 -180 -170 - 160 -150 -140 -130 --12v -110 -100

-90 -%O

70 160 -50 -40 -30 -20 -10

0

100’00 100.39 100’7% 101’17 101.56 101.95 103.90 104.29 104’6% 105’07 105’46 105’85 107.79 108’1% 108.57 108’96 109’35 109’73 111’67 112’66 112’45 112’83 113.22 113’61 135’54 115’93 116’31 116’70 117’08 117’47 119’40 119.7% 120’16 120’55 120’93 121’32 123’24 123.62 124’01 124’39 124’77 125’16 127’07 127’45 127’84 128’22 128.60 128.9% 129’37 129’75 130’13 130.51 130’89

111’2% 111’67 115’15 115’54 119’01 119’40 122’86 123’24 126.69 127.07

Ei 100 110 120 130 140 150 160 170 180 190

;z 220 230 240 250 260 270 280

-l 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460

130’89 134’70 138.50 142’29 146.06 149.82 153.58 157’31 161.04 164.76 168’46 172’16 175’84 179.51 183.17 186.82 190.45 194-07 197.69 201.29 204’86 208’45 212’02 215.57 219.12 222’65 226.17

;E: 236.65 240.13 243.59 247 04 250.48 253’90 237.32 260.72 264’11 267’49

131.27 135’08 138.88 142’66 146’44 150’20 153’95 157.69 161.42 165’13 168’83 172’53 176‘21 179’88 183’53 187.1% 190’81 19444 198’05 101.65 205.23 208.81 212’37 215.93 219’47 223’00 226’52 230.02 233’52 237’00 240’47 243.93 247.3% 250’82 254.24 257’66

131.66 132’04 135’46 135’84 139’26 139’64 143.04 143.42 146.81 147’19 150’57 150’95 154.32 154-70 158’06 158’43 161’79 162’16 165.50 165’87 169.20 169’57 172.90 173’26 176.57 176’94 180.24 180.61 183.90 184.26 187.54 187’91 191.18 191’54 194’80 195.16 198.41 198.77 202’01 202’36 205’59 205.95 209’ 17 209.52 212.73 213.09 216 2% 216.64 219.82 220.1% 223.35 223.70 226’87 227.22 230.37 230’72 233.87 234’22 237.35 237.70 240’82 241.17 244’2% 244’62 247.73 248.07 251’16 251.50 254.59 254.93 258.00 258’31 261’40 261.74 264’79 265’13 268.17 268’50

132’42 132’80 136’22 136’60 140.02 140’39 143’80 144’17 147’57 147 94 151.33 151’70 155’07 155’45 158.81 159’1% 162.53 162’90 166’24 166’61 169’94 170-31 173.63 174’00 177’3 1 l&T97 184’63 188’27 191’90 195’52 199’13 202’72 206’31 209.88 213’44 2 16’99 220’53 224‘06 227’57 231’07 234’56 238’04 241’51 244’97 248’41 2,i-85 255.27 253’6%

177’68 181’34 181’99 188’63 192’26 195’88 199’49 203’08 206’67 2 10.24 213’80 217’35 220.88 224.41 227.92 23!‘42 234’91 238’39 241’86 245-3 1 248.76 252.19 255’61 259.02 262.42 265’80 269’1%

262’0% 265’47 268’84

2LO.95 211’31 211‘66 214’15 214.51 214.86 215.22 217-70 218 05 218.41 218’76 221’24 221.59 221’94 222’29 224-76 225.11 225.46 225.81 228.27 228’62 228.97 229.32 231‘77 232’12 232’47 232,82 235.26 235.61 235’96 236.31 238.74 239 09 239’43 239’78 242.20 242’55 242’90 243.24 245’66 246.00 246’35 246.69 249.10 249.45 249.79 250.13 252’53 252’88 253.22 253.56 255.95 256.29 256.64 256’98 259.36 259.70 260’04 260.38 262’76 266’14 269.5 I

Resistance-ohms

133’18 133’56 133.94 134.32 134’70 136.98 137’36 137.74 138’12 138’50 140’77 141’15 141’53 141’91 142’29 144.55 144-93 145’31 145’68 146.06 148’32 148’70 149’07 149’45 149’82 152’08 152’45 152’83 153.20 153.58 155.82 156’19 156’57 156 94 157.31 159.55 159’93 160.30 160’67 161’04 163.27 163.65 164’02 16-1’39 164’76 166’98 167.35 167’72 168’09 168.46 170’68 171’05 171’42 17 1’79 172.16 174’37 174.74 175’10 175’47 17.5’84 178’04 181’71 185.36 189’00 192’63 196.24 199’95 203’44 207.02 210‘59

178’41 178.78 ii9.14 182’07 182’44 1%2’%0 185’72 186’09 186’45 189’36 189’72 190’09 192’99 193.35 193’71 196’60 196.96 197.33 200’21 200.57 200’93 203.80 204.16 204’52 207.38 207.74 208.10

263.10 263.43 263.77 266.4% 266’82 267.15 269.85 270’19 270’52

179.51 183’ 17 186’82 190’45 194.07 197’69 201’29 204’88 208’45 212’02 215.57 219.12 222’65 226’17 229.67 233’17 236’65 240.13 243.59 247*&I 250’4% 253’90 257.32 260.72 26411 267’49 270.86

80 90

100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 t; . . 420 430 g 440 $ 450 I 460

5 ( Continued ) 8

TABLE 1 TEMPERATURE/RESISTANCE RELATIONSHIP - Contd . .

ki R (0) = 100*00 B cc = 0’003 85O”cY1 s

"C EIPTr68 0 1 2 3 4 5 6 7 8 9

I

CI

“C 10 I EIPT-68 g

470 480 490 500 510 520 530 540 550

co 560 570 580 590

600 610 620 630 640 650 660 670 680 690 700 710 720 730 740 750

270’86 271’20 271.53 271‘87 272’20 272’54 272’88 273’21 273’55 273’88 274’22 274’22 274.55 274’89 275.22 275.56 275’89 276’23 276’56 276’89 277.23 277’56 277’56 277’90 278.23 278’56 278’90 279’23 279’56 279.90 280’23 280.56 280’90 280.90 281’23 281’56 281’89 282’23 282.56 282’89 283.22 283’55 283’89 284.22 284.22 284’54 284-88 285’21 285’54 285’87 286’21 286’54 286.87 287’20 287.53 287’53 287’86 290’83 291’16 294’11 294.44 297.39 297.72 300 65 300’98 303’91 304’23 307’ 15 307.47 310’38 310.70

313’59 313’92 316’80 317’12 319’99 320’31 323.18 323’49 326’35 326’66 329’51 329.82 332’66 332’97 335’79 336’11 338’92 339’23 342.03 342’34 345’13 345’44

288’19 288.52 291’49 291’81 294’77 295.10 298'04 298-37 301’31 301.63 304’56 304’88 307’79 308’12 311’02 311.34

288.85 292’14 295.43 298.70 301’96 305’20 308’44 311’67

3 14’24 314.56 3 14’88 317’44 317.76 3 18.08 320’63 320’95 321’27 323.81 324.13 324’45 326’98 327’30 327’61 330’14 330’45 330’77 333’28 333’60 333’91 336’42 336.73 337.04 339’54 339’85 340’16 342’65 342’96 343.27 345’75 346’06 346.37

289.18 289’51 292’47 292’80 295’75 296’08 299’02 299’35 302’28 302’61 305’53 305’85 308.76 309’09 311’99 312’31

309.41 312’63

315.20 315’52 315’84 318.46 318.72 319’04 321.59 321’91 322’22 324.76 325’08 325’40 327’93 328’25 328.56 331’08 331.40 331’71 332’03 332’34 334’23 334’54 334’85 335’17 335’48 337’36 337.67 337’98 338 29 338’61 340.48 340’79 341’10 341’41 341’72 343’58 343’89 344 20 344.51 344’82 346’68 346’99 347’30 347.60 347’91

290’17 290’50 293’46 293’79 296’74 297.06 300.00 300.33 303’26 303’58 306’50 306’82 307.15 309’73 310’05 310.38 312’95 313.27 3 13.59

316’16 316’48 319.36 319’68 322’54 322’86 325.72 326’03 328’88 329.19

290.83 294’ 11

316’80 3 19’99 323’18 326’35 329’51 332’66

~Kz 342.03 345’13 348.22

348’22 348’53 348’84 349.15 349.45 349’76 350.07 350.38 350.69 350.99 351.30 351’30 351’61 351.91 352.22 352’53 352.83 353.14 353’45 353’75 354’06 35437 354-37 354’67 354’98 355’28 355’59 355’90 356.20 356’51 356’81 357’12 357.42 357’42 357.73 358’03 358.34 358’64 358’95 359.25 359’55 359’86 360.16 360.47 360’47 360’77 361.07 361’38 361.68 361’98 362.29 362’59 362’89 363’19 363.50

470 480 490 500 510 520 530 540 550 560 570 580 590

600 610 620 630 640 650 660 670 680 690 700 710 720 730 740 750

770 780 790

800 810 820 830 840 850

-

363’50 363’80 364.10 364.40 364.71 365’01 365.31 365’61 365’91 366’22 366’52 366’82 367.12 367’42 367’72 368’02 368’32 368.63 368’93 369’23 369’53 369’83 370’13 370’43 370.73 371’03 371.33 371.63 37 1’93 372’22 372.52 372’82 373’12 373’42 373.72 374.02 374’32 37461 374’91 375.21

375’51 375’81 376’10 376’40 376.70 377.00 377’29 378.48 378’78 379.08 379.37 .379’61 379.97 380.26 381’45 381’74 382’04 382’33 382’63 382’92 383’22 384’40 384’69 384’98 385’28 385.57 385’87 386’16 387.34 387.63 387.92 388.21 388’51 388.80 389’09 390.26

377.59 377.89 378’19 380’56 380-85 381’15 383’51 383’81 384.10 386’45 386’75 387.04 389’39 389.68 389’97

Resistance-ohms

366’52 760 369’53 770 372’52 780 375’51 790

378.48 38 1’45 384’40 387.34 390’26

800 810 820 830 840 850

-

IS :2848- 1986

4.3 Tolerances - The tolerance values of resistance thermometers are classified as follows:

Toblerance Class Tolerance

( “C 1 A 0.15 + 0.002 1 t 1 *

B 0.3 + 0.005 1 t 1

4.3.1 Thermometrs of 1OOQ nominal resistance value shall be classified according to degree of conformity with the values of Table 1. The tolerances are given in Table 2, Class A tolerances shall not be applicable to 1OOQ resistance thermometers at temperatures above 650°C.

TABLE 2 TOLERANCES FOR 100 8 THERMOMETERS

TEMPERATURE

( “C ) -

- 200

- 100

0

100

200

300

400

500

600

650

700

800

850

Class A T Class B

(dz°C)

0’55

0.35

0.15

0.35

0’55

0’75

0’95

1’15

1’35

1.45

-

-

-

(fQ)

0’24

0’14

0.06

0’13

0.20

0.27

0’33

0.38

0’43

0’46

-

-

-

l- (ik”C) (&Q)

1’3 0’56

0’8 0’32

0’3 0’12

0.8 0’30

1’3 0’48

1’8 0’64

2’3 0’79

2’8 0’93

3’3 1’06

3’6 1’13

3.8 1.17

4’3 1’28

4’6 1’34

* 1 t 1 = modulus of temperature in degrees Celsius without regard to sign.

10

IS :2848- 1986

Fxo. 2 TOLERANCE VALUES AS A FUNCTION OF TEMPERATURE FOR 100 52 THERMOMETERS

11

IS: 2848 - 1986

5. ELECTRICAL SPECIFICATIONS

5.1 Supply Frequency - Thermometers shall be constructed so that they are suitable for use in measuring systems using direct curreut alternating current at frequencies up to 500 Hz.

5.2 Connecting Wire Configuration - Thermometers may be constructed with a variety of internal connecting wire configurations. Identification and designation of the terminals is therefore essential. Figure 3 shows the preferred methods.

5.3 Thermometer Identification - Each thermometer shall be marked to indicate resistance, class, connecting wire configuration, and temperature range, for example:

Pt 100/A/3 -100/+200

lDENflFlCATlON RED WHITE RED RED WHITE

(MARKING OR COLOUR CODING 1

DIAGRAM

CODE

u u

Pt lOO/ /2 P1100/ 13

IDENTIFIC;PTION Efy:si BLUE

CODE PI lOO/ /LC Pt lOO/ /L

Fro. 3 CONNECTION CONFIGURATIONS

If more than one sensing resistor is enclosed in a single sheath, the manufacturer should provide appropriate identification.

5.4 Resistance Values for 10 ohm and 1 ohm. Fundamental Inter- val - When the maximum temperature to be measured exceeds 600°C, elements of lO*OOO-ohm and 1 *OOO 0 ohm fundamental interval may be used. The resistance values of 10.000 ohm and 1.000 0 ohm fundamental interval elements shall be as given in Table 3 and 4 respectively. The tolerances for the values given in Table 3 and 4 shall be agreed between the purchaser and the manufacturer.

12

IS : 2848 . 1986

TABLE 3 RESISTANCE OF lO*OOO-OHM FUNDAMENTAL INTERVAL ELEMENT

( Clause 5.4 )

TEMPERATURE RESISTANCE TEMPERA- RESISTANCE T.QMPERA- TURE TURE

;;

ohm “C ohm

(2) (1) (2) ;:

-220 2’315 200 45’2 76 650 -200 4.422 250 50’015 700 - 150 9,921 300 54’680 750

RESISTANCE

ohm

(2)

85.24 89’33 93.32

-100 15’256 350 59’276 800 97’2 1 -50 20’460 400 63.785 850 100’0

0 25.575 450 68’225 900 104’8

50 30.613 500 72’59 1 950 108’5

100 35’575 550 76’882 1 000 112’1 150 40’463 600 81’100 1 050 115’6

TABLE 4 RESISTANCE OF 1'000 O-OHM FUNDAMENTAL INTERVAL ELEMENT

( Clause 5’4 )

TEMFERATURE RESISTANCE TENPERA- RESISTANCE TEMPERA- RESISTANCE TURE TURE

OC ohm “C ohm

;:

ohm

(1) (2) (1) (2) (2) -220 0.231 5 200 4.527 6 650 8’524 -200 0’442 2 250 5’001 5 700 8.933

-150 0’992 1 300 5.468 0 750 9’332

- 100 1.525 6 350 5’926 8 800 9’721

-50 2’046 0 400 6’378 5 850 10’10 0 2’557 5 450 6’822 5 900 10’48

50 3’061 4 500 7.259 1 950 IO.85

100 3.557 5 550 7’688 2 1 000 11’21 150 4046 3 600 8.110 0 1 050 11’56

IS : 2848 - 1986

6. MARKING

6.1 The resistance thermometer element terminals or external leads shall be clearly and prominently numbered and a diagram provided showing the internal connections of the element. The diagram shall give the grade and the resistance at 0°C of the element. The name or trade-mark of the manufacturer and the country of manufacture shall also be suitably indicated. Normal maximum correct rating shall also be specified and marked.

6.2 The platinum resistance thermometer element may also be marked with the Standard Mark.

NOTE - The use of the Standard Mark is governed by the provisions of the Bureau of Indian Standards Act 1986 and the Rules and Regulations made there- under. The Standard Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well-defined system of inspection, testing and quality control whit h is devised and supervised by RIS and operated by the producer. Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard. Details of conditions under which a licence for the use of the Standard Mark may be granted to manufacturers or producers, may be obtained from the Bureau of Indian Standards.

7. INFORMATION TO BE AVAILABLE FROM THE MANUFAC- TURER

7.1 Electrical Charac‘teristics - To enable an accurate alternating current measuring system to be designed, maximum values of the relevant electrical characteristics ( that is, thermometer capacitance, capacitance to earth, and inductance ) shall be available on request. These data shall bc for ambient temperature and for the maximum intended temperature of use.

7.2 Depth of Immersion

7.2.1 Calibration Immersion Depth - The manufacturer shall declare the calibration immersion depth used in the resistance tests.

7.2.2 Minimum Usable Depth of Immersion - The manufacturer shall declare the minimum usable depth of immersion as determined by the test.

7.3 Thermal Response Time - The manufacturer shall declare the thermal response time in seconds as measured by one of the methods.

7.4 Self-Heating - The manufacturer shall declare the self-heating effect of the thermometer in “C/mW as measured by the methods of 8.5.

7.5 Ohmic Resistance of Internal Connection Wires - The manufacturer shall supply the value of resistance of internal connection wires in two-wire sensors.

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IS : i848 - 1986

The values of resistance of internal connection wires for other configurations shall be made available on request.

8. TYPE TESTS

8.1 Following shall constitute the types tests:

a) Insulation resistance test ( 8.2 ),

b) Resistance accuracy test ( 8.3 ),

c) Thermal response time test ( 8.4 ),

d) Self heating tests ( 8.5 ),

e) Immersion error test ( 8.6 ),

f) Thermo-eletric effect test ( 867 ),

g) Limiting temperatures test ( 8.8 ),

h) Stability test ( 8.9 ),

j) Drop test ( for sealed elements only ) ( 8.10 ),

k) Vibration test ( for sealed elements only ) ( 8.11 ), and

m) Pressure test ( for sealed elements only ) ( 8.12 ).

8.2 Insulation Resistance Test

8.2.1 When the sensing resistor is mounted in its sheath the insulation resistance between’each terminal and sheath shall be measured with a test voltage between 10 V and 100 V dc and under ambient conditions between 15°C and 35°C and at a relative humidity not exceeding 80 percent. The polarity of the test current shall be reversed. In all cases the insulation resistance shall be not less than 100 MQ, when the value has stabilized.

8.2.2 An additional test shall be carried out at a test voltage not exceeding 10 V d.c. with the thermometer at the rated rnaximum temperature. The insulation resistance between each terminal and the sheath shall be not less than that shown in Table 5.

TABLE 5 INSULATION RESISTANCE AT MAXIMUM TEMPERATURE

RATED MAXIWJM TEMPERATURE MINIIXUM: INSULATION RESISTANCE

( “C ) (Ma)

100 to 300 10

301 to 500 2

501 to 850 0.5

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IS : 2848 - 1986

8,3 Resistance Accuracy Test - The resistance calibration of the thermometer element shall be made with the element inserted at least to the calibration immersion depth stated by the manufacturer and with a direct current such that the electrical power dissipated in the element does not cause any temperature rise due to self heating in excess of 20 percent of the tolerance at temperature. Measurement shall be made as given in IS : 2806-1964*. The test shall be made at a sufficient number of points over the working range of the element to establish that the resistance throughout the range lies within the limits specified, the measurement at each point being made with the current both forward and reversed.

8.4 Thermal Response Time - The thermal response time T is the time required for a thermometer to react to a step change of temperature with a resistance change corresponding to a specified percentage of the step change. The response time for a 50 percent change ( T 0.5 ) shall be recorded. In addition the response times for a 10 percent ( T 0.1 ) and 90 percent (I 0.9) changes or other changes may be reeorded if requested.

The value for 63-2 percent change is not recommeded because of possible confusion with the time constant of a simple, single-order device. To some extent, all thermometers exhibit variations from a single-order response.

8.4.1 General Test Requirements - If the response time is measured by changing the temperature of the surrounding medium, the time for the temperature of the test medium to reach 50 percent of its value shall not exceed l/10 of TO.5.

If the response time is measured by plunging the thermometer into a medium of different temperature, the time for the thermometer to reach the final immersion depth shall not exceed l/l0 of T 0.5;

EXAMPLES OF TEST DEVICES ARE DESCRIBED IN APPENDIX A

The response time of the recording instrument shall not exceed l/5 of T 0.5. Each characteristic value within the test shall be calculated as a mean value of a at least three tests, each of which falls typically within f 10 percent of the mean value.

The usable cross-section of test channel is that part of the actual cross- section with substantially uniform temperature and velocity distribution. The thermometer to be tested shall be inserted into the centre of test channel with its axis in a plane perpendicular to the direction of flow. The width of the channel shall be equal to or more than ten times the diameter of the themometer.

*Methods of temperature measurement by electrical resistance thermometer.

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IS : 2848 - 1986

8.4.2 Test Conditions for Flowing Air - The velocity within the usable cross-section should be 3 & 0.3 m/s. The initial temperature shall be between 10°C and 30%. The value of the temperature step shall be more than 10% and less than 20°C. The minimum immersion depth of the thermometer to be tested shall be equal to the sensitive length of the thermometer plus 15 times its diameter. Where the design immersion depth of a thermometer is less than the above mentioned value, the test should be performed at the designed immersion depth. This immersion depth shall be mentioned in the test report.

8.4.3 Test Conditions for Flowing Water - For response times less than 1 the test apparatus should be designed so that the water has no free surface in front of or behind the thermometer so as to avoid problems of air entrainment. The velocity V within the usable cross-section shall be 0.4 f 0.05 m/s. The initial temperature shall be within the limits of 5% and 30%. The temperature step shall be not more than 10°C.

The final temperature of the water shall not vary by more than f 1 percent of the temperature step during the duration of the measurement.

The minimum immersion depth shall be equal to the sensitive length of the thermometer plus five times its diameter,

Where the designed immersion depth of a thermometer is less than above-mentioned value, the test should be performed at designed immersion depth. This immersion depth shall be mentioned in the test report.

8.5 Self-Heating - This test shall be carried out with the thermometer immersed to the declared calibration immersion depth in well-stirred water maintained at the ice point. Suitable apparatus for testing the thermometer immersed to the calibration immersion depth is described in Appendix B.

The steady-state resistance shall be measured with a current such that the power dissipation in the thermometer is not more than 0.1 mW.

In the case of the nominal 1OOQ resistance thermometer the steady- state resistance shall then be measured at the manufacturer’s stated maximum rate current, or 10 mA, whichever is less. The equivalent figure for the nominal 1OsZ thermometer is SO mA. The temperature rise equivalent to the measured increase in resistance shall not exceed 0*3”C.

Nol!E - This test may not be appropriate for certain small thermometers.When the thermometer is operated in gases, additional information on the effect of self- heating should be avialable from the manufacturer if requested.

8.6 Immersion Error - Suitable apparatus for testing the thermometer immersed to the calibration immersion depth is detailed in Appendix C. The test shall made with a measuring current such that the electrical power dissipated in thermometer is not greater than 1.0 mW. The test shall

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IS : 2848 - 1986

consist of slowly decreasing the depth of immersion until the indicated temperature changes by O* 1 “C. The depth of immersion shall than the measured and described as a minimum usable depth of immersion.

8.7 Thermo-Electric Effect - The thermometer may be tested in apparatus shown in Appendix C or in similar equipment.

Their immersion shall be slowly varied between the calibration immersion depth and the maximum practical depth until the electromotive force across the terminals is at its maximum which shall not exceed 2PrV.

8.8 Limiting Temperatures - The thermometer shall be subjected to the upper and lower limits of its temperature range for a period of 250 h at each temperature. The thermometer shall be immersed to at least its declared calibration immersion depth If the lower limit is below the temperature of liquid nitrogen boiling at atmospheric pressure, the latter temperature may be used for this test. The temperature should be allowed to rest at room temperature for a few minutes between the tests.

As a result of these tests the resistance at 0°C shall not have changed by more than the equivalent of 0*15”C for Class A and 0.30% for Class B thermometer. The thermometer shall also be tested to ensure continued compliance with the insulation resistance requirements.

NOTE - Certain thermometers to be used within improved performance at narrower ranges than their total capability should be tested over range of intended use as stated by the user.

8.9 Effect of Temperature Cycling - The thermometer shall be brought slowly to the upper limit of its temperature range, then exposed to air at. room temperature. It shall then be brought slowly to the lower limit of its temperature range then exposed to air at room temperature. At each limit the thermometer shall be immrrsed to at least its declared calibration immersion depth and shall be maintained at the temperature for sufficient time to reach equilibrium. This procedure shall be repeated ten times. As a result of this test the resistance at 0°C shall not have changed by more than the equivalent of 0*15”C for Class A and 0*3@C for Class B thermometers. If the lower limit is below the temperature of liquid nitrogen boiling at atmospheric pressure, the latter temperature may be used for this test. The thermometer shall also be tested to ensure continued compliance with the insulation resistance requirements of 8.2.1. .

NOTE - Certain thermometers to be used with improved performance at shorter ranges than their total capability should be tested over the range of intended use as stated by the user.

8.10 Drop Test - This test is intended to reveal any weakness of construction. The thermometer, complete with head, if any, shall be held with its longitudinal axis horizontal and dropped ten times from a height of 250 mm on to a 6 mm thick steel plate on a rigid floor.

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The thermometer shall be inspected for mechanical damage. It shall also be tested to ensure continued compliance with the insulation resistance requirements and the maintenance of electrical continuity.

8.11 Vibration Test - This test should be conducted if possible with the thermometer mounted in the same manner as that in which it is to be used.

The mounting means shall be rigidly attached to the vibrator and the thermometer shall be vibrated over the frequency range of IOHz to 50OHz with a forcing acceleration of 20 m/s2 to 30 m/G peak-to-peak. The frequency range shall be swept at a rate of one octave per minute for a total period of 150 h.

The vibrations shall be applied to the thermometer in axial and trans- verse directions each for one half of the total period. The frequency and nature of any reasonances shall be noted. The electrical continuity shall be monitored continuously. At the conclusions of this test the thermometer shall be tested to ensure continued compliance with the insulation resistant requirements of 8.2.1. The thermometer shall also be tested to verify that the resistance at the ice point shall not have changed by more than the equivalent of 0*05”C.

8.12 Pressure Test ( for Sealed Elements Only )- The element shall be tested in a hydraulic test chamber containing water and ice in equilibrium and connected electrically to an approp_riate indicator. The pressure of the fluid in the chamber shall be raised to 3.5 MPa and shall be maintained for I5 minutes.

The resistance of the element sha!l not very significantly from that appropriate to the equilibrium temperature corresponding to the pressure applied and when subsequently removed from the chamber, the element shall pass the’tests given in 8.2 and 8.3,

9. ROUTINE TESTS

9.1 Insulation Resistance Test - This test shall be carried out in accordance with 8.2.1 at the room temperature.

9.2 Resistance Tolerance - The resistance calibration of the thermometer shall be within the tolerance values specified in 4.3 when tested with a current such that the electrical power dessipated in the thermometer does not cause a rise of temperature due to self-heating in excess of l/5 the tolerance value at the temperature.

The test for Class A thermometers shall be carried out at two or more temperatures suitably spaced over the stated working range and with the thermometer inserted in the test medium to at least the declared calibration immersion dept ( see 7.2 ).

The test for Class B thermometers shall be carried out at one temperature, normally the ice point.

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f&:2848-1986

APPENDIX A ( Clause 8.4.1 )

EXAMPLE OF TEST DEVICES FOR THERMAL RESPONSE TIME MEASUREMENTS

A-l. Device for Testing in Air

A-l.1 Air is blown through a diffuser and a wire mesh into the test channel having a rectangular cross-section by means of a fan. The thermometer is mounted in the centre of the test channel with the logitudinal axis of the thermometer normal to the direction of air flow.

In front of the thermometer a heatable wire grid is mounted. The temperature step is generated by switching on and off an electrical current through this wire grid.

The 50 percent time of the temperature step generated with the abovementioned wire grid with a wire diameter of 2 x 10-s mm at a velocity of 1 m/s is 15 m/s for example. For testing thermometers with a diameter smaller than 2 mm, the distance between the grid wires should be about 0.5 mm and for thicker thermometers 1 mm to l-5 mm.

CLAMPING DEVICE

FIG. 4 TEST DEVICE FOR TESTING IN AIR

A-2. METHOD OF MEASURING RESPONSE TIME IN WATER OR OTHER LIQUIDS

A-2.1 A cylindrical vessel with a diameter of 300 mm or more and a height of 200 mm or more is filled with the test liquid. The liquid is forced into rotation either by rotating the vessel or by a rotating drum inserted into the centre of the vessel from above.

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-ll--..-..-.__--._ .-_ ..-.

IS : 2848 - 1986

The test liquid is heated to a temperature approximately 104 above ambient. This heating can be effected by various means such as by heating elements placed on outer surface of the vessel.

The thermometer is fixed on the end of a pivoted arm. When the temperature of the liquid and the thermometer is lowered rapidly into the liquid.

The velocity of flow can be controlled by the rotary speed of the liquid and the radial position of the thermometer.

iERMOMETER

\ TO VARIABLE SPEED DRIVE

7

1

l-7 ,ROTATING ORUM

PIVOT POINT

INFRA- VESSEL

TO VARIABLE SPEED

FIG. 5 TEST Dmam FOR SIMPLIFIED TEST IN

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DRIVE

WATER OR OTHER LIQUIDS

IS : 2848 - 1986

APPENDIX B ( Clause 8.5 )

MEASUREMENT OF SELF-HEATING

B-l. An apparatus suitable for measuring self-heating effect is shown in Fig. 6. This consists of a large Dewar flask in which water at the ice point may be circulated past the element under test. Two tubes of brass or other non-corrosive material are suitably supported on opposite sides of the flask over a layer of small lump ice. The remainder of the space is packed with finely crushed ice up to the level of the top of the tubes water at approximately 0°C is poured into the flask until the level is approximately 6 mm above the level of the tubes. A well-insulated cover is placed on top of the Dewar flask with suitable holes to pass the shaft of stirrer paddle situated in one tube and the thermometer element situated in the other tube. The direction of rotation of the stirrer should be such that the watee is driven

COPPER MESH_, /

/! /RESISTANCE ELEMENT STlR,;R ,M~ ,~

DISTILLED WATER AIR SATURATED AT 0 ‘c

/ / I ~-INSULATING cowR

15LlTRE DEWAR FLASK

FINELV CRUSHED ICE

COPPER MESH

FIG. 6 APPARATUS FOR MEASURING SELF-HEATING

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down through the small lump ice before passing up the tube containing the element. Non-corrosive metal gauge across the bottom of the two tubes and round the top of the stirrer well will prevent the circulation of lumps of ice from interfering with the stirring action. Adequate circulation of the water is shown by the pressure of a pronounced vortex in the stirrer well.

APPENDIX C ( Clauses 8.6 and 8.7 )

DETERMINATION OF IMMERSION ERROR AND THERMO-ELECTRIC EFFECT

C-l. The apparatus ( see Fig. 7 ) should consist of a container with a base of phenolio-resin, or other suitable material of similar thermal characteristics ( conductivity not more than 2.5 W/m’% ). The base should be approximately 12 mm thick. The detecting end of element under test should

PLASTK CON1

-ICE WATER

,PCASTIC BAS

.HYPSOMETEA

;AtNER

IE

FIG. 7 SCHEMATIC TEST APPARATUS FOR DETERMINATION OF IMMLRSION ERROR AND THERMO-ELECTRIC EFFECT

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- _.

pass through the centre of the base of the container into a steam hypsometer. There should be means of ad.justing and measuring the depth of imer- sion of the element in the hypsometer.

C-2. The container should contain ice water to a depth of not less than 50 mm and when the element is in position the hold through which it passes should be sealed to prevent water leakage.

C-3. The associated measuring apparatus should be capable of detecting a temperature, change of 0.1 deg C or O-04 ohm. The current passed through the element while measurements are being made should not exceed 2 mA.

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