Function - Endress+Hauser Hart RN221N Manual Del Usuario

2 Function

The device galvanically separates and supplies 4 to 20 mA signal circuits.
Transmitters are connected at the current input - an additional supply unit is
therefore not required. The current signal is available at the output (active out-
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put) for connection to further instrumentation. Bidirectional HART commu-
nication with SMART transmitters is possible using built-in communication
jacks (with R = 250 ).
Measuring circuit monitoring makes a distinction between three operating
mode and outputs one status signal:
1. Current measurement: monitoring the 4 - 20 mA signal for compliance
with NAMUR NE43 specifications.
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2. Evaluation of the HART status byte
3. Evaluation of the E+H-spec. diagnostic command
Using DIP switches, the user specifies for which transmitter status a status sig-
nal is output.
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RN221N can be selected as a HART primary or secondary master. The oper-
ating mode of RN221N can be set on site by means of a DIP switch.
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Automatic switch-off of the HART master RN221N.
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The HART specification states that a maximum of two HART masters may
be present at any one time in a network. A distinction is made between the
"primary master" and the "secondary master" among these two masters. If a
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third HART master is to be included in the network, another master must be
switched off.
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