Thermocouples measurement

In the measuring range of a specified thermocouple type, a measured voltage is converted internally into a temperature according to the set transformation. Since the channel measures a voltage internally, the corresponding measuring error in the voltage measuring range must be used.

The following tables with the specification of the thermocouple measurement apply only when using the internal cold junction.

The EL331x-00xx can also be used with an external cold junction if required. The uncertainties must then be determined for the external cold junction on the application side. The temperature value of the external cold junction must then be communicated to the EL331x-00xx via the process data for its own calculation. The effect on the measurement of the thermocouples must then be calculated on the system side.

The specifications for the internal cold junction and the measuring range given here apply only if the following times are adhered to for thermal stabilization at constant ambient temperature:

after switching on: 60 min
after changing wiring/connectors: 15 min

Specification of the internal cold junction measurement

The EL3318 has an internal cold junction measurement.

Measurement mode		Cold junction
Basic accuracy: Measurement deviation at 23°C, with averaging		< ±3.0°C
Temperature coefficient	Tk	< 40 mK/K

Specification - thermocouple type B

Temperature measurement thermocouple		Type B
Electrical measuring range used		± 75 mV
Measuring range, technically usable		+600°C ≈ 1.792 mV … +1820°C ≈ 13.820 mV
Measuring range, end value (full scale value)		+1820°C
Measuring range, recommended		+750°C … +1800°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type B: approx. 0.05°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 6.3 K ≈ ± 0.35%_FSV
	@ 55°C ambient temperature	± 7.8 K ≈ ± 0.29%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type B:

Specification - thermocouple type C

Temperature measurement thermocouple		Type C
Electrical measuring range used		± 75 mV
Measuring range, technically usable		0°C ≈ 0 mV … +2320°C ≈ 37.107 mV
Measuring range, end value (full scale value)		+2320°C
Measuring range, recommended		0°C … +2000°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type C: approx. 0.07°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 4.9 K ≈ ± 0.21%_FSV
	@ 55°C ambient temperature	± 6.3 K ≈ ± 0.27%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type C:

Specification - thermocouple type E

Temperature measurement thermocouple		Type E
Electrical measuring range used		± 75 mV
Measuring range, technically usable		-100°C ≈ -5.237 mV … +1000°C ≈ 76.372 mV
Measuring range, end value (full scale value)		+1000°C
Measuring range, recommended		-100°C … +1000°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type E: approx. 0.03°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 3.1 K ≈ ± 0.31%_FSV
	@ 55°C ambient temperature	± 3.6 K ≈ ± 0.36%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type E:

Specification - thermocouple type J

Temperature measurement thermocouple		Type J
Electrical measuring range used		± 75 mV
Measuring range, technically usable		-100°C ≈ -4.632 mV … +1200°C ≈ 69.553 mV
Measuring range, end value (full scale value)		+1200°C
Measuring range, recommended		-100°C … +1200°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type J: approx. 0.04°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 3.2 K ≈ ± 0.27%_FSV
	@ 55°C ambient temperature	± 3.7 K ≈ ± 0.31%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type J:

Specification - thermocouple type K

Temperature measurement thermocouple		Type K
Electrical measuring range used		± 75 mV
Measuring range, technically usable		-200°C ≈ -5.891 mV … +1370°C ≈ 54.818 mV
Measuring range, end value (full scale value)		+1370°C
Measuring range, recommended		-100°C … +1200°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type K: approx. 0.04°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 3.0 K ≈ ± 0.22%_FSV
	@ 55°C ambient temperature	± 3.6 K ≈ ± 0.26%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type K:

Specification - thermocouple type L

Temperature measurement thermocouple		Type L
Electrical measuring range used		± 75 mV
Measuring range, technically usable		0°C ≈ 0 mV … +900°C ≈ 52.430 mV
Measuring range, end value (full scale value)		+900°C
Measuring range, recommended		0°C … +900°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type L: approx. 0.03°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 3.1 K ≈ ± 0.34%_FSV
	@ 55°C ambient temperature	± 3.5 K ≈ ± 0.39%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type L:

Specification - thermocouple type N

Temperature measurement thermocouple		Type N
Electrical measuring range used		± 75 mV
Measuring range, technically usable		-100°C ≈ -2.406 mV … +1300°C ≈ 47.513 mV
Measuring range, end value (full scale value)		+1300°C
Measuring range, recommended		0°C … +1300°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type N: approx. 0.04°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 3.4 K ≈ ± 0.26%_FSV
	@ 55°C ambient temperature	± 3.8 K ≈ ± 0.29%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type N:

Specification - thermocouple type R

Temperature measurement thermocouple		Type R
Electrical measuring range used		± 75 mV
Measuring range, technically usable		0°C ≈ 0 mV … +1767°C ≈ 21.089 mV
Measuring range, end value (full scale value)		+1767°C
Measuring range, recommended		+250°C … +1700°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type R: approx. 0.05°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 5.2 K ≈ ± 0.29%_FSV
	@ 55°C ambient temperature	± 6.4 K ≈ ± 0.36%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type R:

Specification - thermocouple type S

Temperature measurement thermocouple		Type S
Electrical measuring range used		± 75 mV
Measuring range, technically usable		0°C ≈ 0 mV … +1760°C ≈ 17.947 mV
Measuring range, end value (full scale value)		+1760°C
Measuring range, recommended		+250°C … +1700°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type S: approx. 0.05°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 5.4 K ≈ ± 0.31%_FSV
	@ 55°C ambient temperature	± 6.7 K ≈ ± 0.38%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type S:

Specification - thermocouple type T

Temperature measurement thermocouple		Type T
Electrical measuring range used		± 75 mV
Measuring range, technically usable		-200°C ≈ -5.603 mV … +400°C ≈ 20.872 mV
Measuring range, end value (full scale value)		+400°C
Measuring range, recommended		-100°C … +400°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 3.3 K ≈ ± 0.83%_FSV
	@ 55°C ambient temperature	± 3.7 K ≈ ± 0.93%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type T:

Specification - thermocouple type U

Temperature measurement thermocouple		Type U
Electrical measuring range used		± 75 mV
Measuring range, technically usable		0°C ≈ 0 mV … +600°C ≈ 33.600 mV
Measuring range, end value (full scale value)		+600°C
Measuring range, recommended		0°C … +600°C
PDO LSB		0.1/0.01°C/digit, depending on PDO setting Note: internally, 16 bits are used for the calculation up to the FSV; depending on the set thermocouple, therefore, jumps in value > 0.01°C occur with "resolution 0.01°C"; e.g. type U: approx. 0.02°C
Uncertainty in the recommended measuring range, with averaging	@ 23°C ambient temperature	± 3.2 K ≈ ± 0.53%_FSV
	@ 55°C ambient temperature	± 3.5 K ≈ ± 0.58%_FSV
Temperature coefficient (Change in the measured value in relation to the change in the ambient temperature of the terminal)		Since the value is highly dependent on the sensor temperature, as can be seen in the specification plot shown below, it must basically be derived from the specification plot. For better approximation, the measurement uncertainty at T_amb = 39°C as the middle point between 23°C and 55°C is also shown informatively in order to illustrate the non-linear curve.

Measurement uncertainty for thermocouple type U: