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Manual Supplement
00809-0200-4853, Rev AB
Rosemount 3051S Series Pressure Transmitter
November 2017
Rosemount 3051S Series Pressure Transmitter
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 percent 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%.
PLINE_SINGLE_DETECT_SENSITIVITY
Adjusts the Upper detection limit. If this value is 0 (default), the Upper 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 – 10000%.
6.22 Determining detection sensitivity
Determining what values to configure for the upper and lower detection limits can be done by
configuring SPM to monitor and trend the standard deviation, and then looking at how the standard
deviation changes when impulse line plug is simulated, by closing the transmitter root valves or manifold
valves.
First SPM needs to be configured to monitor the pressure as described in “SPM configuration and
operation” on page 14. After SPM has been configured, the standard deviation needs to be trended,
either in an EDDL-supported host (such as AMS Device Manager, shown in Figure 22), or in the DCS as
described in “Trending statistical values in control system” on page 17.
Figure 22. Trend of Standard Deviation in AMS Device Manager
After configuring SPM, wait long enough for the SPM to begin updating the percent change in standard
deviation. This will be at least two to three times the SPM Monitoring Cycle.
While the standard deviation is being trended, the impulse line valve (e.g. manifold or root) must be
manually closed. After the impulse line is closed off, note in the SPM trend how much the standard
deviation has changed. In the example in Figure 22 the standard deviation has decreased by 10.9
percent.
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