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Temperature
Sensing Devices
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SECTION
- 7
Technical
Information
Limits
of Error Thermocouples
| Type |
Temperature Range
oC
for Standard Limits of Error
|
Standard Limits
of
Error
|
Temperature
Range oC for Special Limits of Error |
Special
Limits
of Error |
| J |
0-293 |
±2.2oC |
0
to 275 |
±
1.1oC |
| 293
to 760 |
±
0.75% |
275
to 760 |
±
0.4% |
| K |
-200
to -110 |
±
2% * |
|
* |
| -110
to 0 |
±
2.2oC* |
|
* |
| 0
to 293 |
±
2.2oC |
0
to 275 |
±
1.1oC |
| 293
to 1250 |
±
0.75% |
275
to 1250 |
±
0.4% |
| T |
-200
to -67 |
±
1.5%* |
|
* |
| -67
to 0 |
±
1oC* |
|
* |
| 0
to 133 |
±
1oC |
0
to 125 |
±
0.5oC |
| 133
to 350 |
±
0.75% |
125
to 350 |
± 0.4% |
| E |
-200
to -170 |
±
1%* |
|
* |
| -170
to 0 |
±
1.7oC* |
|
* |
| 0
to 340 |
±
1.7oC |
0
to 250 |
±
0.1oC |
| 340
to 900 |
±
0.5% |
250
to 900 |
±
0.4% |
| R |
0
to 600 |
±
1.5oC |
0
to 600 |
±
0.6oC |
| 600
to 1450 |
±
0.25% |
600
to 1450 |
±
0.1% |
| S |
0 to 600 |
± 1.5oC |
0 to 600 |
± 0.6oC |
| 600 to 1450 |
± 0.25% |
600 to 1450 |
± 0.1% |
| B |
800 to 1700 |
± 0.5% |
800 to 1700 |
- |
*
Thermocouples and thermocouple materials are supplied to meet the limits of
error specified or temperatures above 0oC. A thermocouple material
may not confirm to the published sub-zero limits of error
for that material when purchased, unless conformance is agreed
to between customer and supplier.
**
Special limits of error for sub-zero temperatures have not yet been established.
The following limits for calibrations E and T are useful to start discussion
between customer and supplier.
-200 to 0oC
Type E ± 1oC or ± 0.5%, whichever is greater
Type T ± 0.5oC or ± 0.8%, whichever is greater
Sub-zero limits of error for Type J and sub-zero special limits of error
for Type K are not considered because of the characteristics of the materials.
ANSI
Limits of Error Extension Wire and Compensating Extension
Reference Junction 0oC
| Type |
Temperature
Range oC |
Standard |
Special |
| JX |
0
to 200 |
±
2.2oC |
±
1.1oC |
| KX |
0
to 200 |
±
2.2oC |
- |
| TX |
-60
to +100 |
± 1.0oC |
± 0.5oC |
| EX |
0
to 200 |
±
1.7oC |
- |
Compensating
Extension Wire
RX
- SX
(Copper/#11 Alloy) |
0
to 200 |
±
5oC†
± 0.057 mV |
- |
BX
(Copper/Copper) |
0
to 100 |
+0,
-3.7oC
+0, - .033mV |
- |
† The degree
C limits of error are based on a measuring junction temperature greater than
870oC for Types SX and RX, 1000oC for Type BX.
Non
ANSI Limits of Error Thermocouples
| Type |
Temperature
Range, oC |
Limits
of Error |
| W-W,
26% Re |
0
to 427 |
±
4.4oC |
| 427
to 2316 |
±
1% |
| W,
5% Re-W, 26% Re |
0
to 427 |
±
4.4oC |
| 427
to 2316 |
±
1% |
| W,
3% Re-W, 25% Re |
0
to 427 |
±
4.4oC |
| 427
to 2316 |
±1% |
Platinel
II
(Platinel 5355/Platinel 7674) |
0
to 600 |
±
0.10mV |
| 600
to 700 |
±
0.15mV |
| 700
to 1300 |
±
0.20mV |
Non
ANSI Limits of Error Compensating Extension Wire
| Type |
Temperature
Range, oC |
Limits
of Error |
Alloy
200/Alloy 226
for W-W, 26% R |
0
to 260 |
±
0.14mV |
Ally
203/Alloy 225
for W, 3% Re-W 25% Re |
0
to 260 |
±
0.11mV |
Ally
405/Alloy 426
for W, 5% Re-W, 26% Re |
0
to 871 |
±
0.11mV |
Chromel
P/Alloy 30*
for Platinel 5355/ Platinel 7674 |
0
to 100 |
±
1oC |
| 100
to 200 |
±
6.4oC |
*For Extension
wire/thermocouple wire
Junction temperature (both equal) above about 800oC
Type K wire may be used with minimal error.
Limits
of error apply only to thermocouples supplied by the manufacturer. The
calibration of a thermocouple may change because of the influence of such factors
as temperature, temperature cycling, and time.
By JPN
