Endress+Hauser Hart RN221N Manual Del Usuario página 34

34
Configuration options
1. Current mode: RN221N analyzes the current signal in both circuits (sen-
sor and evaluation) in accordance with NAMUR Recommendation NE-
43 and triggers the relay output if the signal is outside the measuring
range of 3.8 mA to 20.5 mA. NAMUR NE-43 defines the ranges for fail-
ure signal detection as follows:
• < 3.6 mA
• > 21 mA
The switching thresholds for the relay output are fixed at 3.7 mA and
20.75 mA.
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The HART signal is not evaluated in the current mode.
2. Evaluation of the HART
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In the HART protocol, a status byte is transmitted with every exchange
of data between the transmitter and HART
operating status of the transmitter is encoded in this status byte.
The individual bits of the status byte are masked by means of a DIP
switch. If the bit mask matches the status byte, the relay output is trig-
gered. Bits 5 and 6 are not masked. The assignment of the status bits to
the DIP switches is given in the table below.
for the lower current range and
for the upper current range
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status byte:
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master. Information on the