Emerson AMS Trex Device Communicator User Manual page 175

User Guide
User Guide
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Figure 5-11: Help text example
DC voltage measurement
Lower than expected
Higher than expected
Low-Frequency noise
Higher than expected
www.
Possible cause
The power supply's voltage
setting may be set too low.
An unexpected voltage drop
may be due to a damaged cable,
corrosion in the terminals, low
impedance to ground, water in
the device terminals, or loose
connections.
There may be more than one
voltage source on the fieldbus
segment.
The power supply's voltage
setting may be set too high.
Possible cause
When the AC adapter is
attached to the Trex unit, it can
appear as low-frequency noise.
.com
Fieldbus Diagnostics application
September 2021
Action
Verify the power supply's
voltage setting is correct. If
necessary, increase the power
supply voltage.
Measure the voltage at several
points on the fieldbus segment
to determine the location of the
unexpected voltage drop. Start
at the power supply and
continue toward the original
measurement point where the
voltage was measured low.
Ensure there is only one voltage
source.
Verify the power supply's
voltage setting is correct. If
necessary, decrease the power
supply voltage.
Action
Disconnect the AC adapter from
the Trex unit to isolate it from
the local power grid.
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