Proline Promag 300 HART Design
Endress+Hauser 17
4.4.1 Additional restrictions for safety-related use
An incorrect output signal that deviates from the value specified in the Operating Instructions
but is still in the range of 4 to 20 mA, is considered a dangerous, undetected failure.
Information on measured error→ 17
For detailed information on the maximum measured error, see the Operating
Instructions → 10
4.5 Safety measured error
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.
For further information on calculating the measured error, see the Technical
Information.
4.5.1 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.
4.5.2 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.
NOTICE
The measuring device's safety-related signal is the 4–20 mA analog output signal
(output; input 1).
All safety measures refer to this signal exclusively.
‣
Please note the following: → 14.
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