Switch Point Non- Repeatability; Temperature Gradient; Long-Term Drift - Endress+Hauser Flowphant T DTT31 Technical Information

DTT31, DTT35
Switch point non-
repeatability

Temperature gradient

Sensor reaction time

Long-term drift

Endress+Hauser
fluid velocity (for example, with water, the greatest sensor sensitivity is recorded in the range from
0.03 to 0.5 m/s).
A
0
Standard characteristic
A, B: Set monitoring ranges of the flow (example)
LOWF 0%: Setting for the minimum fluid velocity occurring in the monitoring range A or B (0% value)
HIF 100%: Setting for the maximum fluid velocity occurring in the monitoring range A or B (100% value)
Temperature
• Accuracy: 2 K (3.6 °F)
• Repeatability: 1 K (1.8 °F)
• Influence of medium temperature: 0.05 %/K of full scale value
Measuring range % of maximum value
(water as medium)
2)
0.03 to 0.5 m/s ≤ 2 %
(0.1 to 1.6 ft/s)
0.03 to 1 m/s ≤ 3 % 2)
(0.1 to 3.28 ft/s)
0.03 to 2 m/s ≤ 5 % 2)
(0.1 to 6.56 ft/s)
2)
0.03 to 3 m/s ≤ 10 %
(0.1 to 9.84 ft/s)
1) The values indicated only apply to the device itself without taking the temperature-dependent change of the
thermo-physical properties of the medium into account. For this reason, we recommend you commission
the device at the process temperature and set the switch points (see ' L earn function' → ä 13)
2) For a Reynolds number > 10,000
In the event of a temperature change of ≥ 0.5 K/min in the medium, temporary display drifts are
possible which can exceed the specified non-reproducibility values of the switch point.
6 to 12 s
0.5% per year under reference operating conditions
Flow rate
Influence of
medium temperature
0.05 %/K
0.10 %/K
0.15 %/K
0.20 %/K
LOWF 0%
HIF 100%
LOWF 0%
B
HIF 100%
A0008181-EN
Influence of
1)
ambient temperature
0.04 %/K
0.05 %/K
0.10 %/K
0.30 %/K
7