Vega VEGABAR 86 User manual

Operating Instructions
Pressure transmitter with ceramic
measuring cell
VEGABAR 86
Secondary Device for electronic di󰀨erential
pressure
With SIL qualication
Document ID: 48048

2
Contents
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
Contents
1 About this document ............................................................................................................... 4
1.1 Function ........................................................................................................................... 4
1.2 Target group..................................................................................................................... 4
1.3 Symbols used................................................................................................................... 4
2 For your safety ......................................................................................................................... 5
2.1 Authorised personnel ....................................................................................................... 5
2.2 Appropriate use................................................................................................................ 5
2.3 Warning about incorrect use............................................................................................. 5
2.4 General safety instructions............................................................................................... 5
2.5 Conformity........................................................................................................................ 5
2.6 SIL qualication according to IEC 61508.......................................................................... 6
2.7 NAMUR recommendations .............................................................................................. 6
2.8 Installation and operation in the USA and Canada ........................................................... 6
2.9 Environmental instructions ............................................................................................... 6
3 Product description ................................................................................................................. 7
3.1 Conguration.................................................................................................................... 7
3.2 Principle of operation........................................................................................................ 8
3.3 Packaging, transport and storage................................................................................... 11
3.4 Accessories.................................................................................................................... 12
4 Mounting................................................................................................................................. 13
4.1 General instructions ....................................................................................................... 13
4.2 Ventilation and pressure compensation.......................................................................... 15
4.3 Combination Primary - Secondary ................................................................................. 17
4.4 Dierential pressure measurement ................................................................................ 18
4.5 Interface measurement .................................................................................................. 18
4.6 Density measurement .................................................................................................... 19
4.7 Density-compensated level measurement ..................................................................... 20
4.8 External housing ............................................................................................................ 22
5 Connecting to power supply................................................................................................. 23
5.1 Preparing the connection ............................................................................................... 23
5.2 Connecting..................................................................................................................... 24
5.3 Single chamber housing................................................................................................. 25
5.4 External housing with version IP68 (25 bar) ................................................................... 26
5.5 Connection example ...................................................................................................... 28
6 Functional safety (SIL) .......................................................................................................... 29
6.1 Objective........................................................................................................................ 29
6.2 SIL qualication.............................................................................................................. 29
6.3 Application area ............................................................................................................. 29
6.4 Safety concept of the parameterization .......................................................................... 30
7 Set up with the display and adjustment module ................................................................ 32
7.1 Parameter adjustment .................................................................................................... 32
7.2 Menu overview ............................................................................................................... 45
8 Diagnosis, asset management and service ........................................................................ 48
8.1 Maintenance .................................................................................................................. 48
8.2 Rectify faults................................................................................................................... 48

3
Contents
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
8.3 Exchanging the electronics module................................................................................ 49
8.4 Exchange process module on version IP68 (25 bar) ...................................................... 49
8.5 How to proceed if a repair is necessary.......................................................................... 50
9 Dismount................................................................................................................................. 51
9.1 Dismounting steps.......................................................................................................... 51
9.2 Disposal ......................................................................................................................... 51
10 Supplement ............................................................................................................................ 52
10.1 Technical data ................................................................................................................ 52
10.2 Calculation of the total deviation..................................................................................... 60
10.3 Practical example........................................................................................................... 61
10.4 Dimensions .................................................................................................................... 63
10.5 Industrial property rights................................................................................................. 72
10.6 Trademark ...................................................................................................................... 72
Safety instructions for Ex areas:
Take note of the Ex specic safety instructions for Ex applications.
These instructions are attached as documents to each instrument
with Ex approval and are part of the operating instructions.
Editing status: 2022-04-20

4
1 About this document
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
1 About this document
1.1 Function
This instruction provides all the information you need for mounting,
connection and setup as well as important instructions for mainte-
nance, fault rectication, the exchange of parts and the safety of the
user. Please read this information before putting the instrument into
operation and keep this manual accessible in the immediate vicinity
of the device.
1.2 Target group
This operating instructions manual is directed to trained personnel.
The contents of this manual must be made available to the qualied
personnel and implemented.
1.3 Symbols used
Document ID
This symbol on the front page of this instruction refers to the Docu-
ment ID. By entering the Document ID on www.vega.com you will
reach the document download.
Information, note, tip: This symbol indicates helpful additional infor-
mation and tips for successful work.
Note: This symbol indicates notes to prevent failures, malfunctions,
damage to devices or plants.
Caution: Non-observance of the information marked with this symbol
may result in personal injury.
Warning: Non-observance of the information marked with this symbol
may result in serious or fatal personal injury.
Danger: Non-observance of the information marked with this symbol
results in serious or fatal personal injury.
Ex applications
This symbol indicates special instructions for Ex applications.
• List
The dot set in front indicates a list with no implied sequence.
1 Sequence of actions
Numbers set in front indicate successive steps in a procedure.
Disposal
This symbol indicates special instructions for disposal.

5
2 For your safety
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
2 For your safety
2.1 Authorised personnel
All operations described in this documentation must be carried out
only by trained, qualied personnel authorised by the plant operator.
During work on and with the device, the required personal protective
equipment must always be worn.
2.2 Appropriate use
As Secondary Device, the VEGABAR 86 is part of an electronic dif-
ferential pressure meaasurement.
You can nd detailed information about the area of application in
chapter " Product description".
Operational reliability is ensured only if the instrument is properly
used according to the specications in the operating instructions
manual as well as possible supplementary instructions.
2.3 Warning about incorrect use
Inappropriate or incorrect use of this product can give rise to applica-
tion-specic hazards, e.g. vessel overll through incorrect mounting
or adjustment. Damage to property and persons or environmental
contamination can result. Also, the protective characteristics of the
instrument can be impaired.
2.4 General safety instructions
This is a state-of-the-art instrument complying with all prevailing
regulations and directives. The instrument must only be operated in a
technically awless and reliable condition. The operator is responsi-
ble for the trouble-free operation of the instrument. When measuring
aggressive or corrosive media that can cause a dangerous situation
if the instrument malfunctions, the operator has to implement suitable
measures to make sure the instrument is functioning properly.
The safety instructions in this operating instructions manual, the na-
tional installation standards as well as the valid safety regulations and
accident prevention rules must be observed by the user.
For safety and warranty reasons, any invasive work on the device
beyond that described in the operating instructions manual may be
carried out only by personnel authorised by the manufacturer. Arbi-
trary conversions or modications are explicitly forbidden. For safety
reasons, only the accessory specied by the manufacturer must be
used.
To avoid any danger, the safety approval markings and safety tips on
the device must also be observed.
2.5 Conformity
The device complies with the legal requirements of the applicable
country-specic directives or technical regulations. We conrm con-
formity with the corresponding labelling.

6
2 For your safety
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
The corresponding conformity declarations can be found on our
homepage.
2.6 SILqualicationaccordingtoIEC61508
The Safety Integrity Level (SIL) of an electronic system is used to as-
sess the reliability of integrated safety functions.
For detailed specication of the safety requirements, multiple SIL
levels are specied according to safety standard IEC 61508. You can
nd detailed information in chapter " Functional safety (SIL)" of the
operating instructions.
The instrument meets the specications of IEC 61508: 2010 (Edi-
tion 2). It is qualied for single-channel operation up to SIL2. The
instrument can be used homogeneously redundant up to SIL3 in
multi-channel architecture with HFT 1.
2.7 NAMUR recommendations
As a Secondary Device, the device is part of an electronic dieren-
tial pressure measurement. It fulls the requirements of the NAMUR
recommendations of the respective Primary Devices.
2.8 Installation and operation in the USA and
Canada
This information is only valid for USA and Canada. Hence the follow-
ing text is only available in the English language.
Installations in the US shall comply with the relevant requirements of
the National Electrical Code (ANSI/NFPA 70).
Installations in Canada shall comply with the relevant requirements of
the Canadian Electrical Code.
2.9 Environmental instructions
Protection of the environment is one of our most important duties.
That is why we have introduced an environment management system
with the goal of continuously improving company environmental pro-
tection. The environment management system is certied according
to DIN EN ISO 14001.
Please help us full this obligation by observing the environmental
instructions in this manual:
• Chapter " Packaging, transport and storage"
• Chapter " Disposal"

7
3 Product description
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
3 Product description
3.1 Conguration
The scope of delivery encompasses:
• Pressure transmitter VEGABAR 86 - Secondary Device
• Ready-made connection cable, unassembled cable gland
The further scope of delivery encompasses:
• Documentation
– Quick setup guide VEGABAR 86
– Safety Manual (SIL)
– Documentation instrument parameters (default values)
– Documentation order-relating instrument parameters (deviation
from default values)
– Test certicate for pressure transmitters
– Instructions for optional instrument features
– Ex-specic " Safety instructions" (with Ex versions)
– If necessary, further certicates
Information:
Optional instrument features are also described in this operating
instructions manual. The respective scope of delivery results from the
order specication.
This operating instructions manual applies to the following instrument
versions.
• Hardware version from 1.0.0
• Software version from 1.0.0
Note:
You can nd the hardware and software version of the instrument as
follows:
• On the type plate of the electronics module
• In the adjustment menu under " Info"
The type label contains the most important data for identication and
use of the instrument:
Scope of delivery
Scope of this operating
instructions
Type label

8
3 Product description
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
7
8
6
4
5
2
3
1
C
C
C
C
C
C
p
p
p
p
p
ary d
y d
ary d
ary d
ary d
evice
evice
evice
evice
evice
v
Connect to
p
rimar
y
Fig. 1: Layout of the type label (example)
1 Product code
2 Field for approvals
3 Technical data
4 Serial number of the instrument
5 QR code
6 Symbol of the device protection class
7 ID numbers, instrument documentation
8 SILidentication
The type label contains the serial number of the instrument. With it
you can nd the following instrument data on our homepage:
• Product code (HTML)
• Delivery date (HTML)
• Order-specic instrument features (HTML)
• Operating instructions, quick setup guide and Safety Manual at the
time of shipment (PDF)
• Test certicate (PDF) - optional
Move to " www.vega.com" and enter in the search eld the serial
number of your instrument.
Alternatively, you can access the data via your smartphone:
• Download the VEGA Tools app from the " Apple App Store" or the
" Google Play Store"
• Scan the DataMatrix code on the type label of the instrument or
• Enter the serial number manually in the app
3.2 Principle of operation
The VEGABAR 86 is a submersible pressure transmitter for level
measurement in wells, basins and open vessels. Its great exibility
through dierent cable and tube versions allows the instrument to be
used in many dierent applications.
Measured products are liquids.
Depending on the instrument version and measurement setup, meas-
ured products can also be viscous or contain abrasive substances.
The VEGABAR 86 Secondary Device is combined with a sensor from
the VEGABAR 80 series for electronic dierential pressure measure-
ment.
Serial number - Instru-
ment search
Application area
Measured products
Electronicdierential
pressure

9
3 Product description
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
2
1
Fig.2:Example,electronicdierentialpressureforinterfacemeasurement
1 VEGABAR 86
2 VEGABAR 86 - Secondary Device
The sensors are connected via a shielded four-wire cable.The meas-
ured value from the Secondary Device is read in and factored into the
calculations. Power supply and parameter adjustment are carried out
through the Primary Device.
Information:
The sensor versions " Relative pressure climate-compensated" as
well as " Double chamber housing" are not suitable for connection of
a Secondary Device.
You can nd further information in chapter " Combination Primary -
Secondary " of this operating instructions.
The VEGABAR 86 Secondary Device is combined with a suitable
sensor from the same device series to an electronic dierential pres-
sure measurement. The dierential pressure measurement consists
then of the Primary Device and Secondary Device.
Information:
The sensor versions " Relative pressure climate-compensated" as
well as " Double chamber housing" are not suitable for connection of
a Secondary Device.
Electronicdierential
pressure

10
3 Product description
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
1
2
Fig.3:Example,electronicdierentialpressureforlevelmeasurementinpres-
surized vessel
1 VEGABAR 86
2 VEGABAR 86, Secondary Device
The sensors are connected via a shielded four-wire cable.The meas-
ured value from the Secondary Device is read in and factored into the
calculations. Power supply and parameter adjustment are carried out
through the Primary Device.
You can nd further information in chapter " Combination Primary -
Secondary " of this operating instructions.
The sensor element is the CERTEC®measuring cell with robust
ceramic diaphragm. The process pressure deects the ceramic
diaphragm and causes a capacitance change in the measuring cell.
This capacitance change is converted into an electrical signal and
outputted as measured value via the output signal.
The measuring cell is available in two sizes:
• CERTEC®(ø 28 mm) with transmitter ø 32 mm
• Mini-CERTEC®(ø 17.5 mm) with transmitter ø 22 mm
A temperature sensor in the ceramic diaphragm of the CERTEC®or
on the ceramic base of the Mini-CERTEC®measuring cell detects the
actual process temperature. The temperature value is output via:
• The display and adjustment module
Measuring system
Measuring system tem-
perature

11
3 Product description
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
Extreme process temperature jumps are also immediately detected
by the ø 28 mm measuring cell. The values are compared with that of
an additional temperature measurement on the ceramic base body.
Within only a few measuring cycles the intelligent sensor electronics
compensates unavoidable measurement deviations due to tempera-
ture shocks. Such shocks cause (depending on the set damping) only
slight, brief changes to the output signal.
Relative pressure: the measuring cell is open to the atmosphere.
The ambient pressure is detected in the measuring cell and compen-
sated. It thus has no inuence on the measured value.
Absolute pressure: the measuring cell contains vacuum and is
encapsulated. The ambient pressure is not compensated and does
hence inuence the measured value.
The following illustration shows the installation of the ceramic measur-
ing cell in the sensor as well as the sealing concept.
1
2
3
4
5
Fig.4:Front-ushinstallationoftheceramicmeasuringcellwithdoubleseal
1 Housing, sensor
2 Measuring cell
3 Lateral seal for measuring cell
4 Additional, front seal for measuring cell
5 Diaphragm
3.3 Packaging, transport and storage
Your instrument was protected by packaging during transport. Its
capacity to handle normal loads during transport is assured by a test
based on ISO 4180.
The packaging consists of environment-friendly, recyclable card-
board. For special versions, PE foam or PE foil is also used. Dispose
of the packaging material via specialised recycling companies.
Transport must be carried out in due consideration of the notes on the
transport packaging. Nonobservance of these instructions can cause
damage to the device.
The delivery must be checked for completeness and possible transit
damage immediately at receipt. Ascertained transit damage or con-
cealed defects must be appropriately dealt with.
Pressure types
Seal concept
Packaging
Transport
Transport inspection

12
3 Product description
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
Up to the time of installation, the packages must be left closed and
stored according to the orientation and storage markings on the
outside.
Unless otherwise indicated, the packages must be stored only under
the following conditions:
• Not in the open
• Dry and dust free
• Not exposed to corrosive media
• Protected against solar radiation
• Avoiding mechanical shock and vibration
• Storage and transport temperature see chapter " Supplement -
Technical data - Ambient conditions"
• Relative moisture 20 … 85 %
With instrument weights of more than 18 kg (39.68 lbs) suitable and
approved equipment must be used for lifting and carrying.
3.4 Accessories
The instructions for the listed accessories can be found in the down-
load area on our homepage.
The protective cover protects the sensor housing against soiling and
intense heat from solar radiation.
Screwed anges are available in dierent versions according to the
following standards: DIN 2501, EN 1092-1, BS 10, ASME B 16.5,
JIS B 2210-1984, GOST 12821-80.
Welded sockets are used to connect the devices to the process.
Threaded and hygienic adapters enable simple adaptation of devices
with standard threaded ttings to process-side hygiene connections.
Storage
Storage and transport
temperature
Lifting and carrying
Protective cover
Flanges
Welded socket, threaded
and hygienic adapter

13
4 Mounting
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
4 Mounting
4.1 General instructions
Note:
For safety reasons, the instrument must only be operated within the
permissible process conditions. You can nd detailed information on
the process conditions in chapter " Technical data" of the operating
instructions or on the type label.
Hence make sure before mounting that all parts of the instrument ex-
posed to the process are suitable for the existing process conditions.
These are mainly:
• Active measuring component
• Process tting
• Process seal
Process conditions in particular are:
• Process pressure
• Process temperature
• Chemical properties of the medium
• Abrasion and mechanical inuences
Protect your instrument against moisture ingress through the following
measures:
• Use a suitable connection cable (see chapter " Connecting to
powersupply")
• Tighten the cable gland or plug connector
• Lead the connection cable downward in front of the cable entry or
plug connector
This applies mainly to outdoor installations, in areas where high
humidity is expected (e.g. through cleaning processes) and on cooled
or heated vessels.
Note:
Make sure that during installation or maintenance no moisture or dirt
can get inside the instrument.
To maintain the housing protection, make sure that the housing lid is
closed during operation and locked, if necessary.
Devices with threaded tting are screwed into the process tting with
a suitable wrench via the hexagon.
See chapter " Dimensions" for wrench size.
Warning:
The housing or the electrical connection may not be used for screw-
ing in! Depending on the device version, tightening can cause dam-
age, e. g. to the rotation mechanism of the housing.
Avoid damages on the device by lateral forces, for example by vibra-
tions. It is thus recommended to x the devices with process tting
Process conditions
Protection against mois-
ture
Screwing in
Vibrations

14
4 Mounting
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
thread G½ of plastic at the installation site via a suitable measuring
instrument holder.
If there is strong vibration at the mounting location, the instrument
version with external housing should be used. See chapter " External
housing".
The permissible process pressure range is specied on the type label
with "MWP" (Maximum Working Pressure), see chapter " Congura-
tion". This applies even if a measuring cell with a measuring range
(order-related) higher than the permissible pressure range of the
process tting is installed.
In addition, a temperature derating of the process tting, e. g. with
anges, can limit the permissible process pressure range according
to the respective standard.
The permissible process pressure range is stated on the type label.
The instrument should only be operated with these pressures if the
mounting accessory used also fulls these values. This should be en-
sured by suitable anges, welded sockets, tension rings with Clamp
connections, sealings, etc.
Higher process temperatures often mean also higher ambient
temperatures. Make sure that the upper temperature limits stated in
chapter " Technical data" for the environment of the electronics hous-
ing and connection cable are not exceeded.
2
1
Fig. 5: Temperature ranges
1 Process temperature
2 Ambient temperature
Depending on the transmitter, the VEGABAR 86 is supplied with a
protective cap or a transport and mounting protection.
Permissible process
pressure (MWP) - Device
Permissible process
pressure (MWP) - Mount-
ing accessory
Temperature limits
Transport and mounting
protection

15
4 Mounting
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
1
2
Fig. 6: VEGABAR 86, transport and mounting protection
1 Transmitter
2 Transport and mounting protection
Remove this protection after mounting and before setting up the
instrument.
In case of slightly contaminated measured media, the transport and
mounting protection can remain on the instrument as an impact pro-
tection during operation.
4.2 Ventilation and pressure compensation
The lter element in the electronics housing has the following func-
tions:
• Ventilation of the electronics housing
• Atmospheric pressure compensation (with relative pressure meas-
uring ranges)
Caution:
The lter element causes a time-delayed pressure compensation.
When quickly opening/closing the housing cover, the measured value
can change for approx. 5 s by up to 15 mbar.
For an eective ventilation, the lter element must be always free from
buildup. In case of horizontal mounting, turn the housing so that the
lter element points downward after the instrument is installed. This
provides better protection against buildup.
Caution:
Do not use a high-pressure cleaner. The lter element could be dam-
aged, which would allow moisture into the housing.
The following paragraphs describe how the lter element is arranged
in the dierent instrument versions.
Filter element - Function

16
4 Mounting
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
1 2 3
4 4 4
Fig.7:Positionofthelterelement-non-Ex,Ex-iaversion
1 Plastic, stainless steel housing (precision casting)
2 Aluminium housing
3 Stainless steel housing (electropolished)
4 Filter element
With the following instruments a blind plug is installed instead of the
lter element:
• Instruments in protection IP66/IP68 (1 bar) - ventilation via capillar-
ies in non-detachable cable
• Instruments with absolute pressure
The process assembly of instruments with Second Line of Defense
(gastight leadthrough) is completely encapsulated. An absolute pres-
sure measuring cell is used so that no ventilation is required.
1
2
Fig.8:Positionofthelterelement-gastightleadthrough
1 Filter element
1
Fig.9:Positionofthelterelement-IP69Kversion
1 Filter element
Filter element - Position
Instruments with Second
Line of Defense
Filter element - Position
IP69K version

17
4 Mounting
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
Instruments with absolute pressure have a blind plug mounted
instead of the lter element.
4.3 Combination Primary - Secondary
In principle, any sensor combination within the VEGABAR 80 series is
allowed. The following requirements must be fullled:
• Conguration Primary Device suitable for electronic dierential
pressure
• Pressure type is identical for both sensors, i.e. relative pressure/
relative pressure or absolute pressure/absolute pressure
• Primary Device measures the higher pressure
• Measurement setup as shown in the following chapters
The measuring range of each sensor is selected such that it ts the
measuring loop. For this, the max. recommended turn down must be
noted. See chapter " Technical data". It is absolutely necessary the
the measuring ranges of Primary and Secondary correspond.
Measurement result = Measured value of Primary (total pres-
sure) - measured value of Secondary (static pressure)
Depending on the application, individual combinations can result, see
following examples:
Data
Application: Level measurement
Medium: Water
Vessel height: 12 m, pressure = 12 m x 1 Kg/m3x 9.81 m/s2 = 1.18 bar
Superimposed pressure: 1 bar
Total pressure: 1.18 bar + 1 bar = 2.18 bar
Instrument selection
Nominal measuring range Primary: 2.5 bar
Nominal measuring range Secondary: 1 bar
Turn Down: 2.5 bar/1.18 bar = 2.1 : 1
Data
Application: Level measurement
Medium: Water
Vessel height: 250 mm, pressure = 0.25 m x 1 Kg/m3x 9.81 m/s2 =
0.025 bar
Superimposed pressure: 350 mbar = 0.35 bar
Total pressure: 0.25 bar + 0.35 bar = 0.375 bar
Instrument selection
Nominal measuring range Primary: 0.4 bar
Nominal measuring range Secondary: 0.4 bar
Turn Down: 0.4 bar /0.025 bar = 16 : 1
The measuring result (level, pressure dierence) as well as measured
value Secondary (static or superimposed pressure) are output by the
Example - large vessel
Example - small vessel
Output measured values

18
4 Mounting
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
sensor. Depending on the instrument version, output as 4 … 20 mA
signal or digitally via HART, Probus PA or Foundation Fieldbus.
To reach the Safety Integrity Level (SIL) for the electronic dierential
pressure, both instruments must be SIL-qualied.
4.4 Dierentialpressuremeasurement
With the Primary/Secondary combination, a gauge dierent measure-
ment can be realized.
2
3
1
Fig.10:Measurementsetupwithaleveldierencemeasurement
1 Primary Device
2 Secondary Device
3 Screen
4.5 Interface measurement
With the Primary/Secondary combination also an interface measure-
ment can be realised.
Requirements for a functioning measurement are:
• Vessel with changing level
• Products with steady densities
• Interface always between the measurement points
• Total level always above the upper measurement point
Measurement setup
Measurement setup

19
4 Mounting
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
12
h
0,8
1,0
Fig.11:Measurementsetupwithinterfacemeasurement,h=distancebetween
thetwomeasuringpoints
1 VEGABAR 86
2 VEGABAR 86 - Secondary Device
The interface measurement is possible in open as well as in closed
vessels.
4.6 Density measurement
With the Primary/Secondary combination also a density measure-
ment can be realised.
Requirements for a functioning measurement are:
• Vessel with changing level
• Distance between the measurement points as large as possible
• Level always above the upper measuring point
Measurement setup

20
4 Mounting
VEGABAR 86 • Secondary Device for electronic dierential pressure
48048-EN-220817
12
h
Fig.12:Measurementsetupfordensitymeasurement,h=distancebetweenthe
twomeasuringpoints
1 VEGABAR 86
2 VEGABAR 86 - Secondary Device
The length distance h of the two sensors should be at least 10 %,
better 20 %, of the nal value of the sensor measuring range. A bigger
dierence increases the accuracy of the density measurement.
Slight density changes cause only slight changes of the measured
dierential pressure. The measuring range must hence be selected
accordingly.
The density measurement is possible in open as well as in closed
vessels.
4.7 Density-compensated level measurement
The Primary/Secondary combination is suitable for density-compen-
satedlevel measurement in an atmospherically open vessel
Keep the following in mind when setting up the measuring system:
• Mount the Primary Device below the min. level
• Mount the Secondary Device above the Primary Devices
• Mount both sensors away from the lling stream and emptying and
protected against pressure shocks from the stirrer
Measurement setup