Running Fieldbus Diagnostics; Dc Voltage And Noise Level Measurement; Signal Level Measurement - Emerson 375 User Manual

Fieldbus Functionality
RUNNING
FIELDBUS
DIAGNOSTICS
DC Voltage and
Noise Level
Measurement
Signal Level
Measurement
The Fieldbus Diagnostics menu lets you run diagnostics
for troubleshooting fieldbus networks and devices. You
can check the DC voltage, the noise level at low
frequencies, and the signal level and communication
status. The selected tests are automatically repeated
and the test results are updated in the Diagnostics
Results screen.
To view the values associated with the status indicators
or the possible causes of the values, run the diagnostic
test, highlight the test on the Diagnostics Results screen,
and tap HELP.
The DC voltage test displays the amount of DC voltage
on a segment, and the noise level test displays the
amount of noise on the segment. The word Limit is
displayed if the DC voltage measurement is out of the
-37 V to 37 V range or if the noise level measurement is
greater than 2.2 V.
These tests display the measurement value,
measurement unit, and one of the status indicators listed
below.
OK - The value is within the acceptable range.
High - The value is greater than the normal values.
Low - The value is lower than the normal values. The
noise level test will not display this status indicator.
Error - There is an error in the measurement or within
the 375 Field Communicator.
The signal level test determines if a 375 Field
Communicator can receive signals from devices on a
segment. To measure the fieldbus signal level, make
sure an LAS is on the segment. Up to 16 different
devices are checked. The word Limit is displayed if the
signal level value is greater than 1.3 V.
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