Emerson Rosemount 3051S Series Reference Manual page 103

Reference Manual
00809-0200-4801, Rev DA
Figure 6-21. PIL Basic Detection Sensitivities
Detection sensitivities are specified as a percent change in the standard deviation from the baseline
value. Note from
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_Sensi-
tivity, and PLINE_Single_Detect_Sensitivity.
The PLINE_Sensitivity parameter provides the means to set a basic detection sensitivity
can be set to the values: High, Medium (default), or Low. Each value has a corresponding upper and lower
limit shown in the table
lower detection limits.
Table 6-3. Basic PIL Detection Sensitivities
PLINE_Sensitivity value
So, for example, if the PLINE_Sensitivity is set to High, then a plugged impulse line will be detected if the
standard deviation either increases by more than 40% above its baseline value, or decreases more than
60 percent below its baseline value.
Note
For GP/AP sensors, the PIL does not check for an increase in standard deviation, and a plugged impulse
line is detected only if the standard deviation goes below the lower limit. For DP sensors, the PIL checks
for both an increase and a decrease in standard deviation.
The upper and lower detection limits can be set to custom values, using the following parameters.
PLINE_Detect_Sensitivity
Adjusts the Lower detection limit. If this value is 0 (default), the Lower limit is determined by PLINE_Sen-
sitivity. If this value is greater than 0, then it overrides the basic sensitivity value. This value can be set in
the range 0 – 100%.
Advanced Pressure Diagnostics
Figure 6-21 that a higher detection limit (% change) actually corresponds to a lower
Table 6-3. Note that setting the basic sensitivity affects both the upper and the
Upper standard deviation limit
High
Medium
Low
Advanced Pressure Diagnostics
Lower standard deviation limit
40%
70%
100%
October 2016
(Figure 6-21). It
60%
70%
80%
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