Temperature Measurement Noise - Data Translation DT9828 User Manual

. The module is operated in a stable environment within the specified limits.
Inclusive of CJC error and input offset, gain, linearity, and long-term stability errors.
Exclusive of thermocouple errors.
Exclusive of noise.
Specifications are valid for 1 year from calibration.

Temperature Measurement Noise

The total temperature measurement noise (short term variation) is the sum of the following
two components:
• The equivalent temperature noise due to the noise of the analog input circuitry.
• The CJC sensor noise in degrees C.
The noise due to the analog input circuitry (volts) is converted to temperature by dividing the
noise voltage by the sensitivity of the thermocouple type being used at the particular
measurement temperature. Thermocouple sensitivities can be derived from commonly
available NIST (National Institute of Standards and Technology) Thermocouple Reference
Tables. The voltage noise from the analog input circuitry is a function of the programmed
throughput rates and the software filter setting.
Table 25 provides maximum expected voltage noise values as well as maximum expected CJC
sensor temperature noise values for a selection of throughput rates.
Throughput
(Samples/s) Moving Average Filter
600
100
60
10
Table 25: Input Voltage Noise and CJC Sensor Noise
μ
Input Voltage Noise ( V pk-pk)
No Filter
3.0
1.5
1.0
0.5
CJC Noise (Degrees C pk-pk)
Moving Average Filter
12.0 0.01
4.0 0.01
3.0 0.01
1.0 0.01
Specifications
No Filter
0.025
0.025
0.025
0.025
97