Measurement Computing WLS-TEMP - Manual (Page 25)

WLS-TEMP Specifications
25
Accuracy
Thermocouple measurement accuracy
Table 4. Thermocouple accuracy specifications, including CJC measurement error
Sensor Type Maximum error (°C) Typical error (°C) Temperature range (°C)
J ±1.499 ±0.507 –210 to 0
±0.643 ±0.312 0 to 1200
K ±1.761 ±0.538 –210 to 0
±0.691 ±0.345 0 to 1372
S ±2.491 ±0.648 –50 to 250
±1.841 ±0.399 250 to 1768.1
R ±2.653 ±0.650 –50 to 250
±1.070 ±0.358 250 to 1768.1
B ±1.779 ±0.581 250 to 700
±0.912 ±0.369 700 to 1820
E ±1.471 ±0.462 –200 to 0
±0.639 ±0.245 0 to 1000
T ±1.717 ±0.514 –200 to 0
±0.713 ±0.256 0 to 600
N ±1.969 ±0.502 –200 to 0
±0.769 ±0.272 0 to 1300
Note 4: Thermocouple measurement accuracy specifications include linearization, cold-junction compensation
and system noise. These specs are for one year, or 3000 operating hours, whichever comes first, and
for operation of the device between 15 °C and 35 °C. For measurements outside this range, add ±0.5
degree to the maximum error shown. There are CJC sensors on each side of the module. The accuracy
listed above assumes the screw terminals are at the same temperature as the CJC sensor. Errors shown
do not include inherent thermocouple error. Please contact your thermocouple supplier for details on
the actual thermocouple error.
Note 5: Thermocouples must be connected to the device such that they are floating with respect to GND (pins
9, 19, 28, 38). The device GND pins are isolated from earth ground, so connecting thermocouple
sensors to voltages referenced to earth ground is permissible as long as the isolation between the GND
pins and earth ground is maintained.
Note 6: When thermocouples are attached to conductive surfaces, the voltage differential between multiple
thermocouples must remain within ±1.4 V. For best results we recommend the use of insulated or
ungrounded thermocouples when possible.
Semiconductor sensor measurement accuracy
Table 5. Semiconductor sensor accuracy specifications
Sensor Type Temperature Range (°C) Maximum Accuracy Error
LM35, TMP35 or
equivalent –40 to 150 ±0.50
Note 7: Error shown does not include errors of the sensor itself. These specs are for one year while operation
of the device is between 15 °C and 35 °C. Please contact your sensor supplier for details on the actual
sensor error limitations.