28
Manual Supplement
00809-0200-4853, Rev AB
Rosemount 3051S Series Pressure Transmitter
November 2017
Rosemount 3051S Series Pressure Transmitter
By default, the value of PLINE_AFFECT_PV_STATUS is “No”, meaning the quality of the pressure
measurement will not be changed if PIL detects a plugged impulse line. Setting this parameter to Yes will
cause the status quality to change to “Uncertain” when a plugged impulse line is detected. Depending
upon the DCS configuration, the “Uncertain” quality could be visible to the operator, or it could affect
the control logic.
If you ever want to re-start the PIL learning process, set the parameter:
PLINE_RELEARN = Relearn
6.21 Configuration of detection sensitivity
Although a few impulse line applications can be configured just by enabling the PIL, the majority of
applications will require configuring the detection sensitivity (that is, the upper and/or lower limit on the
standard deviation at which an impulse line plug will be detected).
Figure 21 illustrates the basic detection sensitivity setting for PIL. In general, a higher sensitivity means
that the PIL is more sensitive to changes in the process dynamics, while a lower sensitivity means that the
PIL is less sensitive to process dynamics changes.
Figure 21. PIL Basic Detection Sensitivities
Detection sensitivities are specified as a percent change in the standard deviation from the baseline
value. Note from Figure 21 that a higher detection limit (% change) actually corresponds to a lower
sensitivity, because a greater change in the process dynamics is required to trigger a plugged impulse
line alert. Likewise, a lower detection limit corresponds to a higher sensitivity.
In PIL, the Detection Sensitivity is determined by 3 parameters: PLINE_SENSITIVITY, PLINE_DETECT_SEN-
SITIVITY, and PLINE_SINGLE_DETECT_SENSITIVITY.
The PLINE_SENSITIVITY parameter provides the means to set a basic detection sensitivity (Figure 21). It
can be set to the values: High, Medium (default), or Low. Each value has a corresponding upper and lower
limit shown in the Ta bl e 12 . Note that setting the basic sensitivity affects both the upper and the lower
detection limits.
Table 12. Basic PIL Detection Sensitivities
PLINE_SENSITIVITY value Upper standard deviation limit Lower standard deviation limit
High 40% - 60%
Medium 70% - 70%
Low 100% - 80%
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