Delta OHM HD2328, Руководство пользователя

Страница: 18 / 20

- - 18
Accuracy of the thermocouple probes:
The tolerance of a type of thermocouple corresponds to the maximum acceptable departure
from the e.m.f. of any thermocouple of that type, with reference junction at 0°C.
The
tolerance is expressed in degrees Celsius, preceded by the sign.
The percentage tolerance is given by the ratio between the tolerance expressed in degrees
Celsius and the measurement junction temperature, multiplied by one hundred.
The thermocouples conforming to regulations must comply with one of the following
tolerance levels, the values of which are reported in the table.
G I (special tolerances)
G II (normal tolerances)
The tolerances refer to the expected thermocouple operating temperature, in agreement with
the thermoelements' diameter.
Tolerance of the thermocouples:
Type of
thermocouple
Range °C G I* G II*
K 0 … +1370°C ±1.1°C or ±0.4% ±2.2°C or ±0.75%
J 0 … +750°C ±1.1°C or ±0.4% ±2.2°C or ±0.75%
T 0 … +400°C ±0.5°C or ±0.4% ±1°C or ±0.75%
E 0 … +750°C ±1°C or ±0.4% ±1.7°C or ±0.5%
K** -200 … 0°C --- ±2.2°C or ±2%
T** -200 … 0°C --- ±1°C or ±1.5%
E** -200 … 0°C --- ±1.7°C or ±1%
* The higher of the two optional limits is the valid one. Example: at 200°C the percentage
tolerance for type K thermocouple, tolerance G II, is ±0.75% and is equal to ±1.5°C.
Therefore, the limit of ±2.2°C is valid. On the other hand, at 600°C the percentage tolerance is
equal to ±4.5°C, and therefore this is the limit to use.
** The thermocouples that meet the limits for temperatures higher than 0°C do not necessarily
meet the limits for the range under 0°C.
EMC standard regulations
Security EN61000-4-2, EN61010-1 level 3
Electrostatic discharge EN61000-4-2 level 3
Electric fast transients EN61000-4-4 level 3,
EN61000-4-5 level 3
Voltage variations EN61000-4-11
Electromagnetic interference susceptibility IEC1000-4-3
Electromagnetic interference emission
EN55020 class B