Process Intelligence And Plugged Impulse Line Diagnostics; Introduction - Emerson Rosemount 3051S Series Reference Manual

Advanced HART Diagnostic Suite
October 2018
7.3 Process Intelligence and Plugged Impulse Line
Diagnostics
7.3.1

Introduction

Process Intelligence and Plugged Impulse Line diagnostics provide a means for early detection of
abnormal situations in the process environment and process connection. The technology is based on the
premise that virtually all dynamic processes have a unique noise or variation signature when operating
normally. Changes in these signatures may signal that a significant change will occur or has occurred in
the process, process equipment, or transmitter installation. For example, the noise source may be
equipment in the process such as a pump or agitator, the natural variation in the DP value caused by
turbulent flow, or a combination of both.
The sensing of the unique signature begins with the combination of the Rosemount 3051S with
Advanced HART Diagnostic Suite and software resident in the diagnostic electronics to compute
statistical parameters that characterize and quantify the noise or variation. These statistical parameters
are the mean, standard deviation, and coefficient of variation (ratio of standard deviation to mean) of the
input pressure. Filtering capability is provided to separate slow changes in the process due to setpoint
changes from the process noise or variation of interest.
standard deviation value is affected by changes in noise level while the mean or average value remains
constant.
changes in the standard deviation and mean.
The calculation of the statistical parameters within the device is accomplished on a parallel software
path used to filter and compute the primary output signal (such as the 4–20 mA output). The primary
output is not affected in any way by this additional capability.
Figure 7-2. Changes in Process Noise or Variability and Effect on Statistical Parameters
Standard Deviation increases or decreases with changing noise level.
104
Figure 7-3 on page 105 shows an example of how the Coefficient of Variation is affected by
00809-0100-4801, Rev HA
Figure 7-2 shows an example of how the
Process Noise
Standard
Deviation
Mean
Advanced HART Diagnostic Suite
Reference Manual