Endress+Hauser iTEMP HART TMT162 Bedienungsanleitung Seite 96

Technical data
Repeatability
Influence of the supply voltage
Long-term stability
Influence of ambient
temperature (temperature
drift)
96
10 to 2000 Ω
Pt200, Pt500, Pt1000, Ni1000
-20 to 100 mV Thermocouple type: C, D, E, J, K, L, N, U
-5 to 30 mV Thermocouple type: B, R, S, T
Sensor transmitter matching
RTD sensors are one of the most linear temperature elements for measurement. However, the
output still needs to be linearized. To significantly improve temperature measurement accuracy, the
TMT162 allows you to utilize two methods to achieve that:
• Customer specific linearization
®
Using the E+H Readwin
programmed with sensor specific curve data. Once the sensor-specific data has been entered, the
TMT162 utilizes this to generate a custom curve.
• Callendar - Van Dusen coefficients
The Callendar - Van Dusen equation is described as:
R
T
where A, B and C are constants, commonly referred to as Callendar - Van Dusen coefficients. The
precise values of A, B and C are derived from the calibration data for the RTD, and are specific to
each RTD sensor.
The process involves programming the TMT162 with curve data for a specific RTD, instead of using
the standard curve.
Sensor transmitter matching using any of the above methods substantially improves the temperature
measurement accuracy of the entire system. This is as a result of the transmitter using the sensor's
actual resistance vs. temperature curve data instead of the ideal curve data.
0.0015% of the physical input range (16 Bit)
Resolution A/D conversion: 18 Bit
≤ ±0.005%/V deviation from 24 V, related to the full scale value
≤ 0.18 °F/year (≤ 0.1 °C/year) or ≤ 0.05%/year
Data under reference conditions. % relates to the set span. The larger value applies.
Total temperature drift = input temperature drift + output temperature drift (see example below)
Effect on the accuracy when ambient temperature changes by 1 K (1.8 °F):
Input 10 to 400 Ω
typ. 0.001% of measured value, min. 1 mΩ
Input 10 to 2000 Ω
typ. 0.001% of measured value, min. 10 mΩ
Input -20 to 100 mV typ. 0.001% of measured value, min. 0.2 μV
Input -5 to 30 mV typ. 0.001% of measured value, min. 0.2 μV
Output 4 to 20 mA typ. 0.001% of span
Typical sensitivity of resistance thermometers:
Pt: 0.00385 * R /K
nominal
Example Pt100: 0.00385 x 100 Ω/K = 0.385 Ω/K
Typical sensitivity of thermocouples:
2000 software or the HART
2
= R [ 1 AT BT + + +
0
Cu: 0.0043 * R /K
nominal
®
handheld the TMT162 can be
3
C T 100 ( – )T ]
Ni: 0.00617 * R
nominal
Endress+Hauser
TMT162
/K