Alert Setup - Emerson Rosemount 5408 Reference Manual

Configuration parameters
March 2023
B.4

Alert setup

B.4.1 Measurement recovery
Measurement recovery time
The Measurement Recovery Time (Echo Timeout) parameter controls the maximum
time from when measurement is lost (e.g. due to process conditions such as foam or
turbulence) until it is annunciated. If measurement is recovered within the time specified
by this parameter, then it will not be annunciated.
Measurement recovery handling
By default, the Measurement Recovery Time is set up automatically by the device based on
the transmitter configuration.
It is recommended to leave the Measurement Recovery Handling at default unless
required by your application. A higher value may be entered to increase robustness and
avoid nuisance alarms. Only enter a lower value if lost measurement is required to be
annunciated within a certain time for your application.
Used measurement recovery time
This is the value used by the transmitter.
B.4.2 Signal quality alert
This section applies only to transmitters ordered with Smart Diagnostics Suite.
Signal Quality is a measure of the product surface echo amplitude compared to the surface
threshold and noise.
The Signal Quality spans from 0 to 10. A low value means that there is a risk for the noise
peak to be mistaken for the product surface peak.
Note
The Signal Quality may not be 10 even if the antenna is clean. The value depends on
antenna type, application conditions, configured surface threshold, as well as the condition
of the antenna.
Build up on the antenna and different surface conditions are factors that can result in a low
Signal Quality value. By setting an alert, the Signal Quality value can be used to schedule
maintenance to clean the antenna, fine-tune the surface threshold, or detect and monitor
adverse surface conditions such as turbulence or foam.
Note
Signal strength fluctuations are common when measuring solids, so Signal Quality alerts
may not be appropriate in this case.
Suitable alert limits vary from application to application. Appropriate value can be
determined by logging Signal Quality over time and viewing maximum/minimum values.
The Signal Quality Alert limit should be at least 1, but a better guideline is 2-3.
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Reference Manual