Temperature Measurement Accuracy - Measurement Computing WebDAQ 316 User Manual

Differen al input
impedance
Input current
Input noise
Gain error
Offset error
Offset error from
source impedance
Cold-junc on
compensa on
accuracy
Warm-up me

Temperature measurement accuracy

Measurement sensi vity represents the smallest change in temperature that a sensor can detect. It is a
func on of noise. The values assume the full measurement range of the standard thermocouple sensor per
ASTM E230–87.
Table 2. Temperature accuracy specifica ons
Parameter
Measurement
sensi vity
The following figures show the errors for each thermocouple type when connected to the WebDAQ 316 with
auto zeroing performed. The figures display the maximum error over a full temperature range, and the typical
error at room temperature. The figures account for gain errors, offset errors, differen al and integral
nonlinearity, quan za on errors, noise errors, 50 Ω lead wire resistance, and cold-junc on compensa on
errors. The figures do not account for the accuracy of the thermocouple itself.
78 MΩ
50 nA
High-resolu on 200 nVrms
mode
High-speed mode 7 µVrms
High-resolu on 0.03% typ at 25 °C
mode 0.07% typ at 0 °C to 60 °C
0.15% max at 0 °C to 60 °C
High-speed mode 0.04% typ at 25 °C
0.08% typ at 0 °C to 60 °C
0.16% max at 0 °C to 60 °C
High-resolu on 4 µV typ, 6 µV max
mode
High-speed mode 14 µV typ, 17 µV max
0 °C to 60 °C Add 0.05 µV per Ω, when source impedance >50 Ω
0.8 °C typ, 1.7 °C max
The device is lying 15 minutes recommended
flat or facing
upward, with a
constant ambient
temperature.
Condi on Specifica on
High-resolu on Type J, K, T, E, N: <0.02 °C
mode Type B, R, S: <0.15 °C
High-speed mode Type J, K, T, E: <0.25 °C
Type N: <0.35 °C
Type B: <1.2 °C
Type R, S: <2.8 °C
WebDAQ 316 User's Guide
page 20