Endress+Hauser Proline t-mass 65 PROFIBUS DA, Руководство по эксплуатации

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Proline t-mass 65 PROFIBUS DP/PA Technical data
Hauser 111
11 Technical data
11.1 Applications
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5
11.2 Function and system design
Measuring principle Mass flow measurement by the thermal dispersion principle.
Measuring system The "t-mass 65" measuring device consists of the following components:
• t-mass 65 transmitter
• t-mass F, t-mass I sensor
Two versions are available:
• Compact version: transmitter and sensor form a single mechanical unit.
• Remote version: transmitter and sensor are installed separately.
11.3 Input
Measured variable • Mass flow
• Gas temperature
• Gas heat flow
Measuring range The measuring range is dependent upon:
• Gas
• Pressure
• Temperature
• Cross-sectional area of pipe or duct
• Use of flow conditioner (t-mass F sensor)
Please refer to Applicator, the Hauser sizing and selection software, for calculation
of the measuring range.
Special applications
High gas velocities (>70 m/s)
In the event of high gas velocities, it is advisable to read in the process pressure dynamically
or to enter the pressure very precisely as a velocity-dependent correction is performed.
Light gases
• Due to the very high thermal conductivity of hydrogen (H

) (9 times that of air) and the
fact that hydrogen is the lightest of all gases, it can prove very difficult to reliably measure
this gas. Depending on the application, the flow rates of hydrogen are often particularly
slow and the flow profiles are not sufficiently developed. It is not unusual for the flows to
be in the laminar range, whereas a turbulent flow regime would be required for optimum
measurement.
• Despite loss of accuracy and linearity in hydrogen applications with low flow rates, the t-
mass 65 measures with good repeatability and is therefore suitable for monitoring flow
conditions (e.g. leak detection).
• A linear, reliable measured value is difficult to obtain in applications with light gases with
a Reynolds number below RE 4000. While this can be improved by making a special
adjustment in the lower flow range, a loss of accuracy and linearity should be expected. It
is advisable to contact your Hauser sales center if your application involves media
with Reynolds numbers below RE 4000.