Entry type: FAQ, Entry ID: 676710, Entry date: 02/21/2008
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How do you assign and identify thermocouples?

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  • Associated product(s)

Principle:
According to the Seebeck effect, when two different metals are combined there is touch voltage at the points of contact, which depends on the temperature.

The thermo material combinations are standardized. The different material properties of a thermocouple determine the different application cases.

The following table shows the assignment of thermocouple types to the various material compositions:
 

Type

Material composition

Temperature range

T

Cu-CuNi (IEC 584) -270 °C - 400 °C

K

NiCr-Ni (IEC 584) -270 °C - 1372 °C

B

PtRh-PtRh (IEC 584) 200 °C - 1820 °C

N

NiCrSi-NiSi (IEC 584) -270 °C - 1300 °C

E

NiCr-CuNi (IEC 584) -200 °C - 900 °C

R

PtRh-Pt (Pt 13%) (IEC 584) -50 °C - 1769 °C

S

PtRh-Pt (Pt 10%) (IEC 584) -50 °C - 1769 °C

J

Fe-CuNi (IEC 584) -210 °C - 1200 °C

C

W-Re(IEC 584) 0 °C - 2320 °C

L

Fe-CuNi (DIN 43714) 0 °C - 760 °C

U

Cu-CuNi (DIN 43714) -200 °C - 600 °C

TXK / TXK (L)

NiCr-CuCr (P8.585-2001) -200 °C - -150 °C

The following table gives an overview of which modules the thermocouples can be connected to.

ET 200S:
 

Type T K B N E R S J C L U TXK
2AI TC ST X X X X X X X X   X    
2AI TC HF X X X X X X X X X X    

ET 200M:
 

Type T K B N E R S J C L U TXK
SM 331 AI 8 x TC X X X X X X X X X X X  
SM 331 AI 8 x TC 16 Bit X X X X X X X X X X X X
SM331 AI 2 x 12 Bit   X   X X     X   X    
SM331 AI 8 x 12 Bit   X   X X     X   X    

ET 200iSP:
 

Type T K B N E R S J C L U TXK
4 AI TC X X X X X X X X   X X  

Note:
Pay attention to the polarity of the thermocouple wires.

Compensating circuit and thermocouple conductors:

Type T (IEC 584)   Type T (IEC 584 EX)

Fig. 01

  • The color of the insulating sleeve and the positive conductor is brown.
  • The color of the negative conductor is white.
  • The color of the insulating sleeve for intrinsically safe circuits is always blue.

Type K (IEC 584)   Type K (IEC 584 EX)

Fig. 02

  • The color of the insulating sleeve and the positive conductor is green.
  • The color of the negative conductor is white.
  • The color of the insulating sleeve for intrinsically safe circuits is always blue.

Type B (IEC 584)   Type B (IEC 584 EX)

Fig. 03

  • The color of the insulating sleeve and the positive conductor is gray.
  • The color of the negative conductor is white.
  • The color of the insulating sleeve for intrinsically safe circuits is always blue.

Type N (IEC 584)  Type N (IEC 584 EX)

Fig. 04

  • The color of the insulating sleeve and the positive conductor is pink.
  • The color of the negative conductor is white.
  • The color of the insulating sleeve for intrinsically safe circuits is always blue.

Type E (IEC 584)   Type E (IEC 584 EX)

Fig. 05

  • The color of the insulating sleeve and the positive conductor is purple.
  • The color of the negative conductor is white.
  • The color of the insulating sleeve for intrinsically safe circuits is always blue.

Type R / S (IEC 584)  Type R / S (IEC 584 EX)

Fig. 06

  • The color of the insulating sleeve and the positive conductor is orange.
  • The color of the negative conductor is white.
  • The color of the insulating sleeve for intrinsically safe circuits is always blue.

Type J (IEC 584)    Type J (IEC 584 EX)

Fig. 07

  • The color of the insulating sleeve and the positive conductor is black.
  • The color of the negative conductor is white.
  • The color of the insulating sleeve for intrinsically safe circuits is always blue.

Type C (IEC 584)  Type C (IEC 584 EX)

Fig. 08

  • The color of the insulating sleeve and the positive conductor is red.
  • The color of the negative conductor is white.
  • The color of the insulating sleeve for intrinsically safe circuits is always blue.

Type L (DIN 43714)

Fig. 09

  • The color of the insulating sleeve is blue.
  • The color of the positive conductor is red.
  • The color of the negative conductor is blue.

Type U (DIN 43714)

Fig. 10

  • The color of the insulating sleeve is brown.
  • The color of the positive conductor is red.
  • The color of the negative conductor is white.

Note:
When you use thermocouples, you must run a temperature compensation. More information on the temperature compensation options when using thermocouples is available in Entry IDs: 19164525; 19163406; 19164641; 19243010