Specifications

Reference Manual
00809-0200-4801, Rev CA
July 2010
Rosemount 3051S
6-2
Statistical Process Monitoring (SPM)
The Advanced Diagnostics Suite features SPM technology to detect changes
in the process, process equipment or installation conditions of the transmitter.
This is done by modeling the process noise signature (using the statistical
values of mean and standard deviation) under normal conditions and then
comparing the baseline values to current values over time. If a significant
change in the current values is detected, the transmitter can generate an
alert. The SPM can perform its statistical processing on either the primary
value of the field device (e.g. pressure measurement) or any other process
variable available in one of the device’s other Fieldbus function blocks (e.g.
the device sensor temperature, control signal, valve position, or measurement
from another device on the same fieldbus segment). SPM has the capability
of modeling the noise signatures for up to four process variables
simultaneously (SPM1-SPM4). When SPM detects a change in the process
statistical characteristics, it generates an alert. The statistical values are also
available as secondary variables from the transmitter via AI or MAI Function
Blocks if a user is interested in their own analysis or generating their own
alarms.
Plugged Impulse Line (PIL) Diagnostics
The Advanced Diagnostics Suite also implements a plugged impulse line
detection algorithm. PIL leverages SPM technology and adds some additional
features that apply SPM to directly detect plugging in pressure measurement
impulse lines. In addition to detecting a change in the process noise
signature, the PIL also provides the ability to automatically relearn new
baseline values if the process condition changes. When PIL detects a plug, a
“Plugged Impulse Line Detected” PlantWeb alert is generated. Optionally, the
user can configure the PIL to, when a plugged impulse line is detected,
change the pressure measurement status quality to “Uncertain”, to alert an
operator that the pressure reading may not be reliable.
IMPORTANT
Running the Advanced Diagnostics Block could affect other block execution
times. We recommend the device be configured as a basic device versus a
Link Master device if this is a concern.
STATISTICAL PROCESS
MONITORING
TECHNOLOGY
Emerson has developed a unique technology, Statistical Process Monitoring,
which provides a means for early detection of abnormal situations in a
process environment. 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.