White paper WP/CORIOLIS/VERIMASS-EN
Mass flowmeter CoriolisMaster
VeriMass on-board verification and diagnostics
Automatic in-situ monitoring of the
meter tubes for possible erosion or
coating.
By Georg Horst & Frank Frenzel
Measurement made easy
Meter technology used for verification
The core of Coriolis mass flowmeters are oscillating tubes. As
soon as mass is flowing through them, a Coriolis force is
affecting the oscillation, creating a phase shift. This effect is
proportional and can be used to measure the mass flow.
While this measurement is independent from the flow pattern
and does not need straight inlet and outlet sections, it
depends on stable tubes being mechanically in balance.
Balanced tubes require very little energy to vibrate. The
amount of energy required is measured as “driver current”.
Every meter leave the factory with well-balanced tubes and
minimized driver current consumption.
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Any mechanical change of the tubes, such as erosion or
coating is very likely to change the balancing of the tubes and
cause higher driver currents to maintain the same level of
oscillation. This fundamental principle can be used to detect
tube changes and can work as in-situ diagnostics.
Mass flowmeter CoriolisMaster
VeriMass on-board verification and diagnostics
As tubes change, imbalances are the most common reason
for measurement errors and creeping measurement offset,
their detection represent a major advancement in Coriolis flow
measurement technology.
Fig. 1:
Oscillating tubes inside a Coriolis flowmeter
Fig. 2:
Distribution of Coriolis forces inside a Coriolis flowmeter
VeriMass technology
VeriMass uses this basic principle and monitors the driver
current to detect possible medium and long term changes and
drifts of the tubes. The major challenge for the use of this kind
of verification is the elimination of any short term process
effects to verification.
Constant process effects such like gas phases in liquids or
major viscosity changes, however cannot be eliminated.
This specific capability of VeriMass is called “Erosion Monitor”.
After installation of the flowmeter an initial fingerprint (also:
initial baseline) is created. The user defines a calibration
period, in which the meter “learns” the normal behavior of the
flowmeter in this specific application. It detects the driver
current, eliminates any short term effects and defines the
underlying “initial baseline” of the driver current. This selfcalibration is important to adapt VeriMass to possible
demanding processes such as high viscosity fluids, temporary
gas phases in liquids or liquid drops in gases.
All these processes can be verified by using the selfcalibration capability of VeriMass. The calibration period / selflearn duration can be a few minutes up to several weeks. It is
even possible to install the flowmeter, activate the selfcalibration fingerprint period and the process itself starts only
after a few days. All this is considered and does not affect the
quality of the verification.
The noisiness of the driver current signal during the selfcalibration period defines the tightness of the alarm threshold.
Smoother process will be monitored with tighter alarm limits
than noisier processes. This avoids possible false alarms.
The self-calibration period also defines the monitoring period.
At the end of each period the newly found baseline is
compared to the fingerprint period. If the baseline exceeds the
fingerprint baseline including the defined tolerances an alarm
is set and communicated. This is automatically repeated and
does not need further interaction with the flowmeter.
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2 WP/CORIOLIS/VERIMASS-EN | Mass flowmeter CoriolisMaster
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2,5
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100
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G11930
Fig. 3:
Principle of VeriMass fingerprint and in-situ verification
Driver Signal
Basline initial
Alarm limit
2nd Baseline
3rd Baseline
xn Baseline
1 Calibration period / self learn duration 2 1st monitoring period 3 2nd monitoring period 4 xn monitoring period
The table below shows the kind of processes where this type of verification works best.
Type of process or change of tubes
Suitability of VeriMass
Coating of tubes
+++
Erosion of tubes
++
Remarks
Erosion needs to cause imbalances of the tube to create
more energy consumption. Typical erosion issues do
create imbalances.
Any kind of liquid processes with only small viscosity
+++
changes and only temporary gas bubbles
Liquids with changing densities
+++
Changing densities hardly affect the driver current
Liquids with erratic viscosities including changes of
-
Hardly possible
50 mPas or more
Gases with occasional liquid drops
+++
Liquids with changes of different fluids with significantly
+
different viscosities
Yes, if the changes were present during the fingerprint
period
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Mass flowmeter CoriolisMaster | WP/CORIOLIS/VERIMASS-EN 3
Mass flowmeter CoriolisMaster
VeriMass on-board verification and diagnostics
How to handle VeriMass
Through the CoriolisMaster DTM
There are different ways to handle and to operate VeriMass.
Through local LCD display of the flowmeter
Fig. 5:
DTM solution offers three different access methods
A Control system – DTM B Local HART modem
C Local operating interface adapter (TTG)
1 DTM in Control system 2 CoriolisMaster DTM
3 Communication DTM of the HART modem 4 HART modem
5 ABB HART communication DTM 6 Infrared data link
The DTM offers all interaction capabilities also provided by the
display. Additionally the generation of a verification report is
offered. The user can enter date and identification details of
the operator checking the verification and generate two types
of reports. Either a short one focusing on the erosion monitor
or including alarm status, event log and alarm history or a
complete version also showing the parameter settings.
The VeriMass option is available for all FCB100 and FCB400,
as well as FCH100 and FCH400 models.
If meters are not ordered with activated VeriMass, the option
can be activated in field at any time by entering a meter
specific activation code available with our ABB Service
organization.
Fig. 4:
Part of the parameter menu of the CoriolisMaster flowmeter
The fingerprint self-calibration can be started by activating
“Start Adjust”. Beside automatic alarm limit definitions, a
manual mode can be selected. Once started, the monitoring is
fully automatic.
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4 WP/CORIOLIS/VERIMASS-EN | Mass flowmeter CoriolisMaster
Fig. 6:
CoriolisMaster DTM erosion monitor page
Mass flowmeter CoriolisMaster | WP/CORIOLIS/VERIMASS-EN 5
Mass flowmeter CoriolisMaster
VeriMass on-board verification and diagnostics
Example of VeriMass verification report – Meter status summary: Good
6 WP/CORIOLIS/VERIMASS-EN | Mass flowmeter CoriolisMaster
Mass flowmeter CoriolisMaster | WP/CORIOLIS/VERIMASS-EN 7
Mass flowmeter CoriolisMaster
VeriMass on-board verification and diagnostics
8 WP/CORIOLIS/VERIMASS-EN | Mass flowmeter CoriolisMaster
Example of VeriMass verification report – Meter status summary: Questionable, conduct further tests
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Summary
VeriMass offers the automatic monitoring of the meter tubes
for possible erosion of coating. It uses the basic principle that
imbalanced meter tubes require more energy to keep the tube
oscillation stable. This innovative procedure was found and
tested in the field and represents a “simple to use” method to
detect the number one source of errors for Coriolis
flowmeters. A report generation capability completes the
offering.
— Detection of coating or erosion of the tubes.
— Monitoring of all vital meter parts that influence the
performance and accuracy of the meter.
— Simple report generation with trend visualization.
More information in the data sheet, operating instructions on
the webpage at abb.com/flow.
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Mass flowmeter CoriolisMaster | WP/CORIOLIS/VERIMASS-EN 9
Notes
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Notes
Mass flowmeter CoriolisMaster | WP/CORIOLIS/VERIMASS-EN 11
ABB Limited
Process Automation
Howard Road, St. Neots
Cambridgeshire, PE19 8EU
UK
Tel:
+44 (0) 870 600 6122
Fax:
+44 (0)1480 213 339
Mail: [email protected]
ABB Inc.
Process Automation
125 E. County Line Road
Warminster PA 18974
USA
Tel:
+1 215 674 6000
Fax:
+1 215 674 7183
ABB Automation Products GmbH
Process Automation
Dransfelder Str. 2
37079 Goettingen
Germany
Tel:
+49 551 905-0
Fax:
+49 551 905-777
www.abb.com/flow
Note
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3KXF411012R2801
WP/CORIOLIS/VERIMASS-EN 09.2015
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