Field Communicator Menu Trees . . . . . . . . . . . . . . . . . . . page 7-41
OVERVIEWThe Advanced HART Diagnostic Suite is an extension of the Rosemount 3051S
Series of Instrumentation and takes full advantage of the scalable architecture.
The 3051S SuperModule™ Platform generates the pressure measurement while
the diagnostic electronics board is mounted in the PlantWeb housing and plugs
into the top of the SuperModule. The electronics board communicates with the
SuperModule and produces standard 4 – 20 mA and HART outputs while adding
advanced diagnostic capability.
NOTE
When a new SuperModule is connected to the diagnostic electronics board for the
first time, the transmitter will be in alarm state until pressure range is specified.
The Advanced HART Diagnostics Suite is designated by the option code “DA2” in
the model number. All options can be used with DA2 except the following:
•Foundation Fieldbus protocol (Output code F)
•Wireless (Output code X)
•Quick Connect (Housing code 7J)
•Junction box (Housing code 2A, 2B, 2C, 2J)
•Remote display (Housing code 2E, 2F, 2G, 2M)
The HART Diagnostic transmitter has seven distinct diagnostic functions that can
be used separately or in conjunction with each other to detect and alert users to
conditions that were previously undetectable, or provide powerful troubleshooting
tools.
7-1
Rosemount 3051S Series
1. Statistical Process Monitoring (SPM) – SPM technology detects 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, standard deviation, and coefficient of
variation) under normal conditions and then analyzing the recorded
baseline values to current values over time. If a significant change in the
current values is detected, the transmitter can generate HART alerts or
analog alarms, depending on user configuration. The condition is time
stamped and is also noted on the LCD.
The statistical values are also available as secondary variables from the
transmitter via HART. Users can trend their process noise signature,
perform their own analysis or generate their own alarms or alerts based
on the secondary variables. Trending of statistical values in an analog
system can be done with the Smart Wireless THUM Adapter or
Rosemount 333 Tri-Loop. Refer to pages 7-33 and 7-34 for more details.
2. Power Advisory Diagnostic – This diagnostic functionality detects
changes in the characteristics of the electrical loop that may jeopardize
loop integrity. This is done by characterizing the electrical loop after the
transmitter is installed and powered up in the field. If terminal voltage
deviates outside of user configured limits, the transmitter can generate
HART alerts or analog alarms.
3. Diagnostic Log – The transmitter logs up to ten device status events,
each associated with the time stamp of when the event occurred.
Referencing this log allows for better understanding of the device health
and can be used in conjunction with device troubleshooting.
4. Variable Log – The transmitter logs the following values: Minimum and
Maximum Pressure and Minimum and Maximum Temperature with
independent time stamped values. The transmitter also logs total
elapsed time in over-pressure or over-temperature conditions and
number of pressure or temperature excursions outside of sensor limits.
5. Process Alerts – These are configurable alerts for both process pressure
and sensor temperature. Users can receive a HART alert if pressure or
temperature exceeds threshold limits. The time stamp of when the alert
occurred and the number of alert events is also recorded in the
transmitter. When alert is active, this notification is displayed on the LCD.
6. Service Alerts – This is a configurable service reminder that generates a
HART alert after user-specified time has expired. When alert is active,
this notification is displayed on the LCD.
7. Time Stamp – The diagnostic electronics board includes an embedded
Operational Hours clock whose purpose is two-fold.
a. Provides the total number of operating hours of the transmitter.
b. Provides an elapsed “Time Since” event indication or time stamping
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October 2010
for all diagnostics.
7-2
All time values are non-volatile and displayed in the following format:
YY:DDD:hh:mm:ss (years:days:hours:minutes:seconds). The time
stamping capability significantly enhances the user’s ability to
troubleshoot measurement issues, particularly transient events that may
be too fast to capture with DCS or PLC trending or historian capabilities.
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October 2010
Rosemount 3051S Series
USER INTERFACEThe 3051S with Advanced HART Diagnostic Suite can be used with any asset
management software that supports Electronic Device Description Language
(EDDL) or FDT/DTM.
Advanced HART Diagnostics is best viewed and configured using the latest
Device Dashboard interface based on Human Centered Design concepts.
The Device Dashboard can be obtained with DD revision 3051S HDT Dev. 3
Rev. 1.
The following screen shots are taken from Emerson Process Management’s
AMS™ Device Manager, version 10.5. All screens shown are based on the
Device Dashboard interface.
Figure 7-1. Device Dashboard
Diagnostic Action
Settings
Figure 7-1 is the landing screen for the 3051S with Advanced HART
Diagnostic Suite. The device status will change if any device alerts are active.
Graphical gauges provide quick reading of the primary purpose variables.
Shortcut buttons are available for the most common tasks.
Each diagnostic allows the user to select a type of action to take if the
diagnostic is tripped.
None – Transmitter provides no indication that any trip values were exceeded
or the diagnostic is turned off.
Alert Unlatched – Transmitter generates digital HART alert and does not
affect the 4 – 20 mA signal. When conditions return to normal or within
threshold levels, the alert is automatically cleared.
Alert Latched – Transmitter generates digital HART alert and does not affect
the 4 – 20 mA signal. When conditions return to normal, an alert reset is
required to clear the status. This type of alert action is recommended if a 3rd
party alert monitor software is likely to miss alerts due to slow polling of HART
data.
Alarm – Transmitter drives mA output to the configured Failure Alarm level
(HIGH or LOW).
7-3
Reference Manual
Process Noise
Standard
Deviation
Mean
00809-0100-4801, Rev FA
Rosemount 3051S Series
October 2010
STATISTICAL PROCESS
MONITORING
IntroductionStatistical Process Monitoring (SPM) 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.
The sensing of the unique signature begins with the combination of the
Rosemount 3051S pressure transmitter 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 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. Figure 7-2 shows an
example of how the standard deviation value is affected by changes in noise
level while the mean or average value remains constant. Figure 7-3 shows an
example of how the coefficient of variation is affected by changes in the
standard deviation and mean.
Figure 7-2. Changes in process
noise or variability and affect on
statistical parameters
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.
Standard Deviation increases or decreases with changing noise level.
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Mean
Standard
Deviation
Coefficient of
Variation
00809-0100-4801, Rev FA
October 2010
Rosemount 3051S Series
Figure 7-3. CV is the ratio of
Standard Deviation to Mean
CV is stable if Mean is proportional to Standard Deviation.
SPM provides statistical information to the user in two ways. First, the
statistical parameters can be made available to the host system directly via
HART communication protocol or HART to other protocol converters. Once
available, the system can make use of these statistical parameters to indicate
or detect a change in process conditions. In the simplest example, the
statistical values may be stored in a data historian. If a process upset or
equipment problem occurs, these values can be examined to determine if
changes in the values foreshadowed or indicated the process upset. The
statistical values can then be made available to the operator directly, or made
available to alarm or alert software.
The second way for SPM to provide statistical information is with software
embedded in the 3051S. The 3051S uses SPM to baseline the process noise
or signature via a learning process. Once the learning process is completed,
the user can set thresholds for any of the statistical parameters. The device
itself can then detect significant changes in the noise or variation, and
communicate an alarm via the 4 – 20 mA output and/or alert via HART.
Typical applications are detection of plugged impulse lines, change in fluid
composition, or equipment related problems.
OverviewA block diagram of the SPM diagnostic is shown in Figure 7-4. The pressure
process variable is input to a module where basic high pass filtering is
performed on the pressure signal. The mean (or average) is calculated on the
unfiltered pressure signal, the standard deviation calculated from the filtered
pressure signal. These statistical values are available via HART and handheld
communication devices like the 375 Field Communicator or asset
management software like Emerson Process Management’s AMS™ Device
Manager. The values can also be assigned as secondary variables from the
device for 4-20 mA communication to the user through other devices like the
Smart Wireless THUM or Rosemount 333 HART Tri-loop.
7-5
Rosemount 3051S Series
Process
Variable
Statistical
Calculations
Module
Learning
Module
Decision
Module
Standard Outputs
(4-20 mA / HART)
Control Inputs
Outputs
HART alert /
4-20 mA alarm
Resident in Transmitter
Statistical Parameters
Baseline
Values
Figure 7-4. Statistical Process
Monitoring diagnostic resident in
transmitter
SPM also contains a learning module that establishes the baseline values for
the process. Baseline values are established under user control at conditions
considered normal for the process and installation. These baseline values are
made available to a decision module that compares the baseline values to the
most current statistical values. Based on sensitivity settings and actions
selected by the user via the control input, the diagnostic generates alarms,
alerts, or takes other actions when a significant change is detected in either
value.
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October 2010
7-6
Reference Manual
Learning/Verifying
Monitoring
User Initiatives
Compute mean,
std. dev. for
3 min.
Sufficient
Noise?
Compute 2nd
mean, std. dev.
for 3 min.
System
Stable?
System
Stable?
“Insufficient
Dynamics”
Change Status
Compute mean (X)
and std. dev. ( )
Decrease in
> 60%?
“Low Variation
Detected”
“High Variation
Detected”
Increase in
> 60%?
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
00809-0100-4801, Rev FA
October 2010
Figure 7-5. Simplified SPM
flowchart
Rosemount 3051S Series
Further detail of the operation of the SPM diagnostic is shown in the
Figure 7-5 flowchart. This is a simplified version showing operation using the
default values. While SPM continuously calculates the mean, standard
deviation, and coefficient of variation values, the learning and decision
modules must be turned on to operate. Once enabled, SPM enters the
learning/verification mode and the status will be “Learning”. The baseline
statistical values are calculated over a period of time controlled by the user
(Learning/Monitoring Period; default is 3 minutes). A check is performed to
make sure that the process has a sufficiently high noise or variability level
(above the low level of internal noise inherent in the transmitter itself). If the
level is too low, the diagnostic will continue to calculate baseline values until
the criteria is satisfied (or turned off). A second set of values is calculated and
compared to the original set to verify that the measured process is stable and
repeatable. During this period, the status will change to “Verifying”. If the
process is stable, the diagnostic will use the last set of values as baseline
values and change to “Monitoring” status. If the process is unstable, the
diagnostic will continue to verify until stability is achieved. The stability criteria
are also user defined.
7-7
Rosemount 3051S Series
In the “Monitoring” mode, statistical values of mean, standard deviation, and
coefficient of variation are continuously calculated, with new values available
every second. When using mean and standard deviation as the SPM
variables, the mean value is compared to the baseline mean value. If the
mean has changed by a significant amount, the diagnostic can automatically
return to the “Learning” mode. The diagnostic does this because a significant
change in mean is likely due to a change in process operation and can result
in a significant change in noise level (i.e. standard deviation) as well. If the
mean has not changed, the standard deviation value is compared to the
baseline value. If the standard deviation has changed significantly and
exceeds configured sensitivity thresholds, this may indicate a change has
occurred in the process, equipment, or transmitter installation and a HART
alert or analog alarm is generated.
For DP flow applications where the mean pressure is likely to change due to
changing process operation, the recommended SPM variable for process
diagnostics is the coefficient of variation. Since the coefficient of variation is
the ratio of standard deviation to mean, it represents normalized process
noise values even when the mean is changing. If the coefficient of variation
changes significantly relative to the baseline and exceeds sensitivity
thresholds, the transmitter can generate a HART alert or analog alarm.
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00809-0100-4801, Rev FA
October 2010
Assigning Statistical
Values to Outputs
Device Dashboard
Fast Keys
2, 2, 5, 1
NOTE
SPM diagnostic capability in the Rosemount 3051S HART pressure
transmitter calculates and detects significant changes in statistical parameters
derived from the input pressure signal. These statistical parameters relate to
the variability of and the noise signals present in the pressure signal. It is
difficult to predict specifically which noise sources may be present in a given
pressure measurement application, the specific influence of those noise
sources on the statistical parameters, and the expected changes in the noise
sources at any time. Therefore, Rosemount cannot absolutely warrant or
guarantee that SPM will accurately detect each specific condition under all
circumstances.
The statistical values of mean, standard deviation, and coefficient of variation
can be made available to other systems or data historians via HART
communication. WirelessHART adaptor, such as the Smart Wireless THUM
can also be used to obtain additional variables. Devices that convert HART
variables to analog 4-20 mA outputs, such as the Rosemount 333 Tri-Loop
can also be used.
Statistical values can be assigned to be 2nd variable, 3rd variable, or 4th
variable. This is accomplished through Variable Mapping. See Figure 7-6.
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October 2010
Figure 7-6. Selection of
statistical values as secondary
variables
Rosemount 3051S Series
SPM Configuration For inexperienced users, guided setup is recommended. Guided setup walks
Device Dashboard
Fast Keys
Figure 7-7. Guided Setup Menu
2, 1, 2, 1
the user through settings that configure the SPM diagnostic for most common
usage and applications.
The rest of the configuration section explains the parameters for manual
configuration of SPM diagnostic.
7-9
Rosemount 3051S Series
Figure 7-8. Statistical Process
Monitoring main screen
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00809-0100-4801, Rev FA
October 2010
The SPM Status screen shows overview information for the diagnostic.
The process for operation of the SPM diagnostic is:
•Configure the diagnostic using Baseline Configuration and Detection
Configuration screens.
•Turn on the diagnostic from the SPM Status screen.
The configuration process starts with Baseline Configuration, Figure 7-9 on
page 7-11. The configurable fields are:
SPM Variable:
This is the statistical variable to be used for SPM diagnostic detection.
Stdev & Mean (default)
Standard deviation and mean of the process are calculated. Users can set
independent sensitivity thresholds for both statistical variables.
Coefficient of Variation (CV)
CV is calculated from the ratio of standard deviation to mean and is better
suited for DP flow applications where the mean pressure is likely to
change due to changing process operation. CV puts standard deviation in
context of the mean and is represented as a % value.
7-10
Reference Manual
3 min.
5 min.
10 min.
00809-0100-4801, Rev FA
October 2010
Figure 7-9. Baseline
Configuration screen
Rosemount 3051S Series
Figure 7-10. Effect of
Learn/Monitor Period on
Statistical Values
Learn/Monitor Period:
This is the learning and monitoring time period that SPM diagnostic uses to
sample the pressure signal. The mean and standard deviation or coefficient of
variation values determined during the learning period will become the
Baseline values. Decreasing this period can speed up the set up time and is
recommended for stable process operations. Increasing this value will give a
better baseline value for noisier processes. If false trips for “High Variation
Detected” are occurring due to rapid changes in the process and statistical
value, increasing the learning period is recommended. The
Learning/Monitoring Period is always set in minutes. The default value is 3
minutes and the valid range is 1 to 60 minutes.
Figure 7-10 illustrates the effect of Learn/Monitor Period on the statistical
calculations. Notice how a shorter sampling window of 3 minutes captures
more variation (e.g. plot looks noisier) in the trend. With the longer sampling
window of 10 minutes, the trend looks smoother because SPM uses process
data sampled over a longer period of time.
7-11
Rosemount 3051S Series
Power Interruption Action
This is used to direct what the diagnostic should do in the case of a power
interruption or if the diagnostic is manually disabled and then enabled. The
options are:
Monitor (default)
When SPM restarts, the diagnostic returns to the Monitoring mode
immediately and uses the baseline values computed before the
interruption.
Relearn
When SPM restarts, the diagnostic enters the Learning mode and will
recalculate new baseline values.
Low Pressure Cut-off
This is the minimum pressure required to operate the diagnostic with
Coefficient of Variation selected as the statistical variable. The coefficient of
variation is a ratio of standard deviation to mean and is defined for non-zero
mean values. When the mean value is near zero, the coefficient of variation is
sensitive to small changes in the mean, limiting its usefulness. Default value
is 1% of upper sensor limit.
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October 2010
Insufficient Variability
The SPM diagnostic uses process noise to baseline the process and detect
abnormal situations. Typically the Insufficient Variability check is on to ensure
there is sufficient noise for proper operation. In a quiet application with very
minimal process noise, this setting can be turned off. The default setting is
ON.
ParameterDefinition
On (default)Perform insufficient variation check
OffDo not perform insufficient variation check
Standard Deviation Difference, Mean Difference
If these difference values are exceeded during the Verification mode, SPM
diagnostic will not start Monitoring mode and will continue verifying the
baseline. If SPM diagnostic will not leave the Verification mode, these values
should be increased. If the diagnostic still remains in the Verification mode
with the highest level, the Learning/Monitoring period should be increased.
Table 7-1. Standard Deviation Verification Criteria
ParameterDefinition
NoneDo not perform any verification checks for standard deviation.
10%If the difference between baseline standard deviation value and the
verification value exceeds 10%, diagnostic will stay in Verification
mode.
20% (default)If the difference between baseline standard deviation value and the
verification value exceeds 20%, diagnostic will stay in Verification
mode.
30%If the difference between baseline standard deviation value and the
verification value exceeds 30%, diagnostic will stay in Verification
mode.
7-12
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00809-0100-4801, Rev FA
October 2010
Figure 7-11. Detection
Configuration screen for
Standard Deviation & Mean
Rosemount 3051S Series
Table 7-2. Mean Verification Criteria
ParameterDefinition
NoneDo not perform any verification checks for mean.
3 Stdev (default)If the difference between baseline mean value and the verification
value exceeds 3 standard deviations, diagnostic will stay in Verification
mode.
6 StdevIf the difference between baseline mean value and the verification
value exceeds 6 standard deviations, diagnostic will stay in Verification
mode.
2%If the difference between baseline mean value and the verification
value exceeds 2%, diagnostic will stay in Verification mode.
The Detection Configuration screen (Figure 7-11 and Figure 7-12) allows for
configuration of sensitivity threshold values for tripping the diagnostic and
how to receive the HART alert or analog alarm.
7-13
Rosemount 3051S Series
Figure 7-12. Detection
Configuration screen for
Coefficient of Variation
Reference Manual
00809-0100-4801, Rev FA
October 2010
Figure 7-13. Preset sensitivity
levels
Standard Deviation Sensitivity, Mean Sensitivity
Shows the current sensitivity level for detecting changes in standard deviation
or mean. Users can choose from preset values of High, Medium, and Low.
Custom sensitivity levels can also be configured.
Coefficient of Variation Sensitivity
Shows the current sensitivity level for detecting changes in the coefficient of
variation. Users can choose from preset values of High, Medium, and Low.
Custom sensitivity levels can also be configured.
Figure 7-13 illustrates the differences in preset sensitivity limits of High,
Medium, and Low. The preset High sensitivity setting (e.g. 20%) will cause the
SPM diagnostic to be more sensitive to changes in the process profile. The
preset Low sensitivity setting (e.g. 80%) will cause the SPM diagnostic to be
less sensitive as a much greater change in the process profile is needed to
trip the alert.
7-14
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