Safety function
Proline Promass 500
18
Hauser
L
CAUTION
Pay particular attention to the following:
‣
It is the responsibility of the user to assess the influence of the process conditions and the
medium on the measurement result in safety equipment, particularly the occurrence of
two-phase mixtures, buildup, abrasion and corrosion, for example.
‣
In the case of liquids with a low boiling point or liquids in suction lines, it is important to
ensure that the vapor pressure is not undershot and that the liquid does not start to boil.
‣
Please ensure that there is never any outgassing of the gases naturally contained in many
liquids. Sufficiently high system pressure prevents the occurrence of these effects.
‣
Make sure that cavitation does not occur as it can affect the operating life of the measuring
tubes.
‣
If gaseous media are used, turbulences can occur at high flow velocity rates, e.g. if valves
are half-closed. This can cause the measured values to fluctuate.
No special measures need to be taken into consideration for single-phase, liquid media with
properties similar to water.
Further information on the suitability of the measuring device for safety-related
operation is available from your Hauser sales center.
5.2.4
Information on measured errors
When the measured value is transmitted via the 4–20 mA current output, the measuring
device's relative measured error is made up of the contribution of the digitally determined
measured value and the accuracy of the analog current output. These contributions, which are
listed in the device documentation, apply under reference operating conditions and can
depend on the sensor version ordered. If process or ambient conditions are different, there are
additional contributions, e.g. temperature or pressure, which are also listed.
For further information on calculating the measured error, see the Technical
Information. → 11
5.2.5
Power supply to the 4–20 mA current output
Overvoltages at the 4–20 mA current output (passive, output; input 1) - caused by a fault in
the supply unit, for example - can result in a leak current in the device's input protection unit.
This may lead to falsification of the output signal by more than the specified error or the
minimum failure current (3.6 mA) can no longer be set due to the leak current.
‣
Use a 4–20 mA power supply unit with either voltage limitation or voltage monitoring.
NOTICE
The safety-related connection values depend on the Ex approval.
‣
Pay attention to the safety-related connection values.
For detailed information on the connection values, see the Safety Instructions.→ 12
5.2.6
HART communication
The measuring device also communicates via HART or WirelessHART in the SIL mode. This
comprises all the HART features with additional device information.
Summary of Contents for HART Proline Promass 500
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