ABB 800xA Operation page 116

Description
If the data values are well outside the reasonable range, then the Heat Exchanger
Asset Monitor will assume the values as invalid data. Potential causes for data
values that are invalid include faulty transmitters. When invalid data values are
detected, the Heat Exchanger Asset Monitor will set the subconditions for
conditions directly affected by the relevant inputs to Instrumentation Error.
Additionally, the Heat Exchanger Asset Monitor will not proceed with training or
attempt to monitor efficiency when the bad values continue to exist. During such
times, most output values from the Heat Exchanger Asset Monitor will not be
updated and their quality will be read as BadLastKnownValue. The trend report
will show dashed lines during this period due to the bad quality of the logged data.
Since the Output Records will not be updated, Asset Optimization will report the
Asset Monitor to be in BAD status, with an error string stating that various output
records will not be set. This error is not cause for concern, as this is the intended
behavior in order to correctly signal the logs and trends that the Heat Exchanger
Asset Monitor is not generating valid outputs when the inputs are bad. When the
input values return to a more reasonable range, normal training and monitoring will
resume.
The Asset Monitor will consider any data to be invalid that is equivalent to any of
the following:
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– Delta P Hot: Alternatively, P In and P Out for the hot side may be used to
calculate Delta P.
– Delta P Cold: Alternatively, P In and P Out for cold side may be used to
calculate Delta P.
Individual temperatures (T Hot In, T Hot Out, T Cold Out, T Cold In) less than
0 degrees Kelvin.
Individual temperatures (T Hot In, T Hot Out, T Cold Out, T Cold In) greater
than 10,000 degrees Kelvin.
Temperature differences ((T Hot In - T Hot Out), (T Hot In - T Cold Out), or
(T Cold Out - T Cold In) less than 0 degrees Kelvin.
For a hot side condensing heat exchanger, the temperature difference
(T Hot In - T Hot Out) less than -10 degrees Kelvin.
For cold side evaporating heat exchanger, the temperature difference
(T Cold Out - T Cold In) less than -10 degrees Kelvin.
Section 9 Heat Exchanger Asset Monitor (HXAM)
3BUA000150-600