VEGA PULS43 User Manual
Operating Instructions
VEGAPULS 43
®
4 … 20 mA; HART
compact sensor
Contents
Safety information ........................................................................ 3
Note Ex area ................................................................................ 3
1 Product description .................................................................. 4
1.1 Function................................................................................. 4
1.2 Application features ............................................................. 6
1.3 Adjustment ............................................................................ 7
2 Types and versions ................................................................... 9
2.1 Type survey .......................................................................... 9
2.2 Antenna ............................................................................... 10
3 Mounting and installation ..................................................... 11
3.1 General installation instructions ........................................ 11
3.2 Measurement of liquids ..................................................... 14
3.3 Measurement in standpipe (surge or bypass tube) ...... 15
3.4 False echoes ...................................................................... 21
3.5 Common installation mistakes ........................................... 22
Contents
4 Electrical connection .............................................................. 25
4.1 Connection and connection cable .................................... 25
4.2 Connection of the sensor .................................................. 27
4.3 Connection of the external indicating instrument
VEGADIS 50 ....................................................................... 31
4.4 Configuration of measuring systems ............................... 32
5 Set-up ........................................................................................ 40
5.1 Adjustment media .............................................................. 40
5.2 Adjustment with PC ............................................................ 40
5.3 Adjustment with adjustment module MINICOM ............... 42
5.4 Adjustment with HART® handheld ................................... 48
6 Diagnostics............................................................................... 50
6.1 Simulation ............................................................................ 50
5.2 Error codes ........................................................................ 50
2 VEGAPULS 43 – 4 … 20 mA
26626-EN-041227
Contents
7 Technical data .......................................................................... 51
7.1 Technical data ..................................................................... 51
7.2 Approvals ........................................................................... 56
7.3 Dimensions ......................................................................... 57
Supplement..................................................................................... 59
Safet y Manual ................................................................................. 59
1 General ............................................................................... 59
1.1 Validity ................................................................................. 59
1.2 Area of application ............................................................... 59
1.3 Relevant standards ............................................................. 59
1.4 Determination of safety-related characteristics .................. 60
2 Planning .............................................................................. 61
2.1 Low demand mode ............................................................... 61
2.2 High demand or continuous mode ....................................... 61
2.3 General ................................................................................ 61
3 Set-u p ................................................................................. 62
3.1 Mounting and installation..................................................... 62
3.2 Adjustment instructions and parameter adjustment ........... 62
3.3 Configuration of the processing unit ................................... 62
4 Reaction during operation and in case of failure ............. 63
5 Recurring function test ....................................................... 63
6 Safety-related characteristics ........................................... 64
SIL declaration of conformity .................................................... 65
CE conformity declaration......................................................... 66
Safety information
Please read this manual carefully, and also take
note of country-specific installation standards
(e.g. the VDE regulations in Germany) as well
as all prevailing safety regulations and accident prevention rules.
For safety and warranty reasons, any internal
Note Ex area
Please note the attached safety instructions
containing important information on installation
and operation in Ex areas.
These safety instructions are part of the operating instructions manual and come with the Ex
approved instruments.
work on the instruments, apart from that involved in normal installation and electrical connection, must be carried out only by qualified
VEGA personnel.
26626-EN-041227
VEGAPULS 43 – 4 … 20 mA 3
1 Product description
Product description
Sensors used in the food and pharmaceutical
industries must meet very high demands:
they must have long-term stability, they must
be accurate, robust, easy to set up, chemically resistant and flawlessly hygienic. Many
level sensors meet those demands only
halfway. Radar sensors, which are otherwise
widely used, are not usually found in hygienic
and sterile applications because their antennas are difficult to clean. The newly developed VEGAPULS 43 radar sensor was designed especially for areas of application in
hygienic and sterile production. Radar sensors are ideal because they operate without
touching the medium, are free of wear and
ageing, and perform well regardless of pressure (-1 … +40 bar) or temperature
(-40°C … +150°C). The new antenna design
of VEGAPULS 43, having no recesses or
gaps, presents a smooth surface (like a
smooth vessel wall) to CIP and SIP processes. It allows all the methods of modern,
environment-friendly system hygiene and
has, of course EHEDG, FDA and 3A approvals. The sensor faces the medium only with a
small, extremely dense TFM-PTFE surface
through which it transmits very small
(0.15 mW) radar pulses. A very fast, intelligent electronics creates from the resulting
echoes a precise image of the surroundings
and calculates from the pulse running time
the level in the vessel every 0.1 s. This value
is then outputted as a 4 … 20 mA signal.
Compared with the PTFE commonly used in
hygienic applications, the improved TFMPTFE has a far denser polymer structure and
a noticeably higher surface quality (Ra < 0.8).
As a result, proven radar technology is now
available for sterile production processes.
The spectrum of applications for the new
radar sensor is broad and varied: serum
production, face cream, fruit juice, etc.
Due to their small housing dimensions and
process fittings, the compact sensors are
unobstrusive and, above all, cost-effective
monitors of your product levels. With their
integrated display, they enable highprecision level measurements and can be
used for applications in which the
advantages of non-contact measurement
could never before be realized.
VEGAPULS radar sensors are perfectly
adapted to two-wire technology. The supply
voltage and the output signal are transmitted
via one two-wire cable. The instruments
produce an analogue 4 … 20 mA signal as
output, i.e. measurement signal.
1.1 Function
Radio detecting and ranging: Radar.
VEGAPULS radar sensors are used for noncontact, continuous distance measurement.
The measured distance corresponds to a
filling height and is outputted as level.
Measuring principle:
emission – reflection – reception
Extremely small 26 GHz radar signals are
emitted from the antenna of the radar sensor
as short pulses. The radar pulses reflected
by the sensor environment and the product
are received by the antenna as radar echoes. The running period of the radar pulses
from emission to reception is proportional to
the distance and hence to the level.
4 VEGAPULS 43 – 4 … 20 mA
26626-EN-041227
Product description
Meas.
distance
emission - reflection - reception
The radar pulses are emitted by the antenna
system as pulse packages with a pulse
duration of 1 ns and pulse intervals of
278 ns; this corresponds to a pulse package
frequency of 3.6 MHz. In the pulse intervals,
the antenna system operates as a receiver.
Signal running periods of less than one billionth of a second must be processed and
the echo image evaluated in a fraction of a
second.
1 ns
278 ns
Hence, it is possible for the radar sensors to
process the slow-motion pictures of the sen-
sor environment precisely and in detail in
cycles of 0.5 to 1 second without using time-
consuming frequency analysis (e.g. FMCW,
required by other radar techniques).
Nearly all products can be measured
Radar signals display physical properties
similar to those of visible light. According to
the quantum theory, they propagate through
empty space. Hence, they are not depend-
ent on a conductive medium (air), and they
spread out like light at the speed of light.
Radar signals react to two basic electrical
properties:
- the electrical conductivity of a substance
- the dielectric constant of a substance.
All products which are electrically conductive
reflect radar signals very well. Even slightly
conductive products provide a sufficiently
strong reflection for a reliable measurement.
All products with a dielectric constant ε
greater than 2.0 reflect radar pulses suffi-
ciently (note: air has a dielectric constant εr of
1). Signal reflectivity grows stronger with
increasing conductivity or increasing dielec-
tric constant of the product. Hence, nearly all
substances can be measured.
r
Pulse sequence
VEGAPULS radar sensors can achieve this
through a special time transformation procedure which spreads out the more than 3.6
million echo images per second into a quasi
slow-motion picture, then freezes and processes them.
%
50
40
30
20
10
5 %
5
0
2
0
25 %
4 6 8 12 14 16 18
10
40 %
20
ε
Reflected radar power dependent on the dielectric
constant of the measured product
tt
Time transformation
26626-EN-041227
VEGAPULS 43 – 4 … 20 mA 5
r
Product description
With standard flanges of DN 50 to DN 150,
ANSI 2“ to ANSI 6“ or G 1½ A and 1½“ NPT,
the sensor antenna systems can be adapted
to various products and measuring environments.
The high-quality materials can also withstand
extreme chemical and physical conditions.
The sensors deliver stable, reproducible
analogue or digital level signals with reliability
and precision.
Continuous and reliable
Unaffected by temperature, pressure and
atmosphere content, VEGAPULS radar sensors are used for quick and reliable continuous level measurement of widely varying
products.
%
0,03
0,02
0,01
0
100 500 1000 1300 ˚C
0
0,018 %
Temperature influence: Temperature error absolutely
zero (e.g. at 500°C 0.018 %)
%
10
5
0,29 %
0
10
0
1,44 %
20 30 40 60
50
Pressure influence: Error with pressure increase very
low (e.g. at 50 bar 1.44 %)
0,023 %
2,8 %
70 80 90 110 120 130 140
100
3,89 %
bar
1.2 Application features
Applications
• level measurement of any liquid
• measurement also in vacuum
• all slightly conductive materials and all
substances with a dielectric constant > 2.0
• measuring range 0 … 10 m (DN 50).
measuring range 0 … 20 m (DN 80, DN
100, DN 150).
Two-wire technology
• power supply and output signal on one
two-wire cable (Loop powered)
• 4 … 20 mA output signal or HART
signal.
Rugged and abrasionproof
• non-contact
• high-resistance materials
Exact and reliable
• accuracy 0.05 %.
• resolution 1 mm
• unaffected by noise, vapours, dusts, gas
compositions and inert gas stratification
• unaffected by varying density and temperature of the medium
• measurement in pressures up to 16 bar
and product temperatures up to 150°C.
Communicative
• integrated measured value display
• optional display module separate from
sensor
• adjustment with detachable adjustment
module, pluggable in the sensor or in the
external display
• adjustment with HART
®
handheld
• adjustment with the PC.
®
output
Approvals
• CENELEC, ATEX, PTB, FM, CSA, ABS,
LRS, GL, LR, FCC.
6 VEGAPULS 43 – 4 … 20 mA
26626-EN-041227
Product description
1.3 Adjustment
Every measurement set-up is unique. For
that reason, every radar sensor needs some
basic information on the application and the
environment, e.g. which level means "empty“
and which level "full“. Beside this "empty and
full adjustment“, many other settings and
adjustments are possible with VEGAPULS
radar sensors.
The adjustment and parameter setting of
radar sensors is carried out with
- the PC
- the detachable adjustment module MINICOM
- the HART
Adjustment with the PC
The set-up and adjustment of the radar sensors is generally done on the PC with the
adjustment software PACT
gram leads quickly through the adjustment
and parameter setting by means of pictures,
graphics and process visualisations.
®
handheld
ware
TM.
The pro-
The PC can be connected at any measuring
site in the system or directly to the signal
cable. It is connected by means of the twowire PC interface converter VEGACONNECT 3
to the sensor or the signal cable. The adjustment and parameter data can be saved with
the adjustment software on the PC and can
be protected by passwords. On request, the
adjustments can be quickly transferred to
other sensors.
2
PLC
2
Adjustment with the PC on the 4 … 20 mA signal and
supply cable or directly on the sensor (figure: a twowire sensor)
2
4 ...20 mA
2
Adjustment with the PC on the analogue 4 … 20 mA
signal and supply cable or directly on the sensor
(four-wire sensor)
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VEGAPULS 43 – 4 … 20 mA 7
Product description
Adjustment with the adjustment module
MINICOM
The small (3.2 cm x 6.7 cm) 6-key adjustment
module with display allows the adjustment to
be carried out in clear text dialogue. The
adjustment module can be plugged into the
radar sensor or into the optional, external
indicating instrument.
Tank 1
m (d)
12.345
Detachable adjustment module MINICOM
Unauthorised sensor adjustments can be
prevented by removing the adjustment module.
ESC
+
-
OK
Adjustment with the HART® handheld
Series 40 sensors with 4 … 20 mA output
signal can also be adjusted with the HART
handheld. A special DDD (Data Device Description) is not necessary - the sensors can
be adjusted with the HART
®
standard menus
of the handheld.
HART Communicator
HART® handheld
To make adjustments, simply connect the
®
HART
handheld to the 4 … 20 mA output
signal cable or insert the two communication
cables of the HART
®
handheld into the ad-
justment jacks on the sensor.
®
ESC
+
-
Tank 1
m (d)
OK
12.345
2
-
Tank 1
m (d)
12.345
+
ESC
OK
4 ... 20 mA
2
4 ...20 mA
2
4
HART® handheld on the 4 … 20 mA signal cable
Adjustment with detachable adjustment module. The
adjustment module can be plugged into the radar
sensor or into the external indicating instrument
VEGADIS 50.
8 VEGAPULS 43 – 4 … 20 mA
26626-EN-041227
Types and versions
2 Types and versions
2.1 Type survey
VEGAPULS 43 sensors are manufactured
with three process connections:
- flange connections (block flanges) in
DN 50, 80, 100, 150, ANSI 2“, 3“, 4“, 6“
- TRI-Clamp 2“
- hygienic fitting DN 50.
Survey of features
General features
• Application preferably for liquids in storage tanks and process vessels with increased
accuracy requirements.
• Measuring range 0 … 10 m or 0 … 20 m.
• Ex approved in Zone 1 (IEC) or Zone 1 (ATEX) classification mark
EEx ia [ia] IIC T6.
• Integrated measured value display.
Survey
Signal outputs
- active (4 … 20 mA)
- passive (4 … 20 mA, loop powered)
Process fitting, optionally available with
- DN 50; ANSI 2“
- DN 80; ANSI 3“
- DN 100; ANSI 4“
- DN 150; ANSI 6“
- TRI-Clamp (50, 80)
- hygienic fitting (50, 80)
Adjustment
-PC
- adjustment module in the sensor
- adjustment module with external indicating instrument
- HART® handheld
Measuring range
- DN 50, ANSI 2“ 0 … 10 m
- DN 80, ANSI 3“ 0 … 20 m
- DN 100, ANSI 4“ 0 … 20 m
- DN 150, ANSI 6“ 0 … 20 m
- TRI-Clamp 50, 80 0 … 10 m
- hygienic fitting 50, 80 0 … 10 m
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VEGAPULS 43 – 4 … 20 mA 9
Types and versions
2.2 Antenna
The antenna is the eye of the radar sensor.
The shape of the antenna, however, doesn’t
give a casual observer the slightest clue on
how carefully the antenna geometry must be
adapted to the physical properties of electromagnetic waves. The hygienic VEGAPULS 43
radar sensors are equipped with an antenna
that can be cleaned as easily as a smooth
vessel wall. The previously used horn and
rod antennas are gone. Only a small coneshaped bulge protrudes into the process
vessel. The small cone acts like a lens that
focuses the radar signals into a high-frequency beam. The relative dielectric constant
of the small 140° PTFE cone represents the
calculation index of the lens. The visible part
of the antenna (small cone), however, does
not give a clue as to how precisely the geometrical form of the antenna has to be
adapted to the physical properties of electromagnetic waves. The shape governs the
focusing of the waves and hence the sensitivity, just as shape governs the sensitivity of
a unidirectional microphone. The production
of such an electromagnetic lens requires
much empirical knowledge in the areas of
high-frequency physics and materials science.
Hygienic design
Beside the aforementioned geometry necessary for antennas used in the food and pharmaceutical industry, the choice of materials
for the newly developed VEGAPULS 43 sensors is critical for cleaning and sterilisation.
Fully automatic cleaning (CIP) and sterilisation (SIP) of entire production facilities (without disrupting production or having to
dismantle and disassemble parts of the
equipment) is, in practice, not an easy task.
Dirt and contaminants get trapped mechanically in pores, fissures, scratches and recesses, and even remain on smooth walls
due to electrostatic attraction.
PTFE is commonly found in hygienic applications. The small plastic cone of the sterile,
pharmaceutical VEGAPULS 43 radar sensor,
which is at the same time antenna and process seal, consists of a TFM-PTFE material.
This is a fluorothermoplastic which has additional distinct advantages compared to PTFE,
such as e.g., reduced load deformation,
denser polymer structure as well as
smoother surface (Ra < 0.8 µm). The other
known advantages of PTFE, such as, e.g.,
higher temperature resistance (< 200°C),
high chemical resistance as well as resistance to brittleness and ageing are still
present or have even been enhanced.
Perfluorelastomers and fluorthermoplasts are
resistant to virtually all chemical media, such
as e.g., amines, ketones, esters, acids (sulphuric acid, phosphoric acid, hydrochloric
acid, nitric acid), alkalis (caustic soda), oxidants, fuels and oils. Beside their use in the
chemical industry, these materials are being
applied more and more in sterilisation and
pharmaceutical technologies. The only limits
to these materials are in applications with
fluorine under high pressure or with liquid
alkali metals (sodium or potassium), where
explosive reactions may occur.
10 VEGAPULS 43 – 4 … 20 mA
26626-EN-041227
Mounting and installation
3 Mounting and installation
3.1 General installation instructions
Measuring range
The reference plane for the
measuring range of the sensor
is the lower edge of the flange.
Keep in mind that in measuring
environments where the medium can reach the sensor
flange, buildup may form on
the antenna and later cause
measurement errors.
Note: The series 40 sensors
are suitable for measurement
of solids only under certain
conditions.
full
Measuring range (operating range) and max. measuring distance
Note: Use of the sensors for applications with solids is limited.
Meas. range
Reference planeempty
max.
max.
min.
False echoes
If flat obstructions in the range of the radar
signals cannot be avoided, we recommend
Flat obstructions and struts cause strong
false echoes. They reflect the radar signal
with high energy density.
diverting the interfering signals with a deflector. The deflector prevents the interfering
signals from being directly received by the
radar sensor. The signals are then so lowInterfering surfaces with rounded profiles
scatter the radar signals into the surrounding
energy and diffuse that they can be filtered
out by the sensor.
space more diffusely and thus generate false
echoes with a lower energy density. Hence,
those reflections are less critical than those
from a flat surface.
Round profiles diffuse radar signals
Profiles with smooth interfering surfaces cause large
false signals
Cover smooth, flat surfaces with deflectors
26626-EN-041227
VEGAPULS 43 – 4 … 20 mA 11
Mounting and installation
Emission cone and false echoes
The radar signals are focused by the antenna system. The signals leave the antenna
in a conical path similar to the beam pattern
of a spotlight. This emission cone depends
on the antenna used. Any object in this beam
cone will reflect the radar signals. Within the
first few meters of the beam cone, tubes,
struts or other installations can interfere with
the measurement. At a distance of 6 m, the
false echo of a strut has an amplitude nine
times greater than at a distance of 18 m.
At greater distances, the energy of the radar
signal distributes itself over a larger area,
thus causing weaker echoes from obstructing surfaces. The interfering signals are
therefore less critical than those at close
range.
If possible, orient the sensor axis perpendicularly to the product surface and keep
vessel installations (e.g. pipes and struts) out
of the emission cone.
The illustrations of the emission cones are
simplified and represent only the main beam
- a number of weaker beams also exist. Under difficult measuring conditions, the antenna location and alignment must be chosen
with the objective of reducing false echoes.
Only giving attention to the size of the useful
echo is not adequate when measuring conditions are unfavourable.
If possible, provide a "clear view“ to the
product inside the emission cone and avoid
vessel installations in the first third of the
emission cone.
Optimum measuring conditions exist when
the emission cone reaches the measured
product perpendicularly and when the emission cone is free from obstructions.
Examples of vessel echoes
The following vessel images show a typical
echo pattern in a vessel. The example shows
a process vessel with a slow double-bladed
stirrer. In the lower area, the vessel is
equipped with heating spirals. A thin, angled
inlet tube ends in the vessel centre between
the stirrer blades.
Empty vessel
In a difficult measuring environment, searching for a mounting location with the lowest
possible false echo intensity will bring the
best results. In most cases, the useful echo
will then be present with sufficient strength.
With the adjustment software PACT
the PC, you can have a look at the echo image and optimise the mounting location.
ware
TM
on
When the vessel is empty, you see the echoes of the vessel installations around the
emission cone. Beside the large bottom echo,
you see a number of additional false echoes.
The false echoes of the vessel installations
are saved during a false echo recording. For
this reason, the false echo recording must be
carried out when the vessel is empty.
12 VEGAPULS 43 – 4 … 20 mA
26626-EN-041227
Mounting and installation
False echoes from the top down:
- first inlet tube fastening
- upper stirrer blade
- second inlet tube fastening
- angled inlet tube
- upper heating tubes
- lower stirrer blade
- remaining heating tubes
- vessel bottom
¼ filling
After filling, the bottom echo is replaced by
the product echo.
The product echo moves to the centre of the
meas. range. At the end of the meas. range,
you now see an echo at a position where the
bottom echo previously was in the empty
vessel. This echo is a multiple echo of the
product echo and is located at twice the
distance of the product echo.
Filled vessel
When the vessel is completely filled, you see
additional multiple echoes at two, three or
four times the distance of the product surface
echo.
½ filling
26626-EN-041227
VEGAPULS 43 – 4 … 20 mA 13
Mounting and installation
3.2 Measurement of liquids
Flange antenna
Horn antenna on DIN socket piece
Radar sensors are usually mounted on short
DIN socket pieces. The lower side of the
instrument flange is the reference plane for
the measuring range. The socket piece
should be as short as possible.
d
h
max.
h
d
Deviating socket dimensions
50 mm/2"
80 mm/3"
100 mm/4"
150 mm/6"
Mounting on a block flange is especially
advantageous. Due to its very shallow recess, it is an ideal solution also for hygienic
and aseptic applications.
max.
100 mm
150 mm
250 mm
400 mm
The flange screws of VEGAPULS 43 must
always be tightened with a torque of approx.
60 Nm so that the PTFE seal is tight.
Dished tank tops can act as paraboloidal
reflectors. If the radar sensor is placed in the
focal point of the parabolic tank top, the radar
sensor receives amplified false echoes. The
radar sensor should be mounted outside the
focal point. Parabolically amplified echoes are
thereby avoided.
Horn antenna directly on the vessel top
If the stability of the vessel will allow it (sensor
weight), flat mounting directly on the vessel
top is a good and cost-effective solution. The
top side of the vessel is the reference plane.
> 400 mm
Mounting on dished tank end
In vessels with dished or rounded tops,
please do not mount the instrument in the
centre or close to the vessel wall.
14 VEGAPULS 43 – 4 … 20 mA
26626-EN-041227
Mounting and installation
3.3 Measurement in standpipe (surge or bypass tube)
General instructions
Measurement in a standpipe is preferred in
vessels which contain many installations, e.g.
heating tubes, heat exchangers or fast-running stirrers. Measurement is then possible
when the product surface is very turbulent,
and vessel installations can cause no false
echoes.
Due to the concentration of the radar signals
within the measuring tube, even products
with small dielectric constants (ε
3) can be reliably measured in surge or by-
pass tubes.
Surge pipe welded
to the tank
Type label
= 1.6 up to
r
Surge pipe in the
socket piece
maxmax
Make sure the required upper vent hole in
the surge pipe is aligned with the sensor
type label.
As an alternative to a surge pipe in the vessel, a pipe antenna system outside the vessel in a bypass tube is also possible.
The surge and bypass tubes must generally
be made of metal. For plastic tubes, a
closed, conductive jacket is always required.
When using a metal tube with plastic inner
coating, make sure that the thickness of the
coating is minimal (approx. 2 … 4 mm).
Align the sensor so that the type label lies on
the same axis as the tube holes or the tube
connection openings. The polarisation of the
radar signals enables a considerably stabler
measurement with this alignment.
Type label
> 300 mm
100 %
Vent hole
ø 5 … 10 mm
Tube flange system as bypass tube
0 %
When mounting a VEGAPULS 43 on a bypass tube (e.g. on a previous floating or
displacer unit), the radar sensor should be
min
without deflector
Pipe antenna system in the tank
with deflector
min
placed approx. 300 mm or more from the
max. level.
Surge pipes which are open at the bottom
must extend over the full measuring range
(i.e. down to 0% level), as measurement is
only possible within the tube. The tube inner
diameter should be max. 100 mm or correspond to the size of the antenna horn.
26626-EN-041227
VEGAPULS 43 – 4 … 20 mA 15
Mounting and installation
For products with small dielectric constants
(< 4), the bypass tube should have a length
greater than would normally be required for
the lower tube connection. Products with
small dielectric constants are partly penetrated by the radar signals, allowing the
tube bottom to produce a stronger echo than
the product (when the bypass tube is nearly
empty). By extending the tube downward,
some liquid remains at the bottom even when
the vessel is completely empty.
Type label
> 300 mm
100 %
0 %
Tube flange system as bypass tube
300 ... 800 mm
Connections to the bypass tube
The connections to the bypass tubes must
be fashioned in such a way that only minimal
reflections are caused by the walls of the
connecting tubes. This is especially important
for the breather connection in the upper part
of the tube. Observe the following points:
• Use small openings for the connection.
• The diameter of the connecting tubes
should not exceed 1/3 of the bypass diameter.
• The tube connections must not protrude
into the bypass tube.
• Large welding beads in the tubes should
be avoided.
• Additional connections to the bypass tube
must lie in the same plane as the upper
and lower vessel connection (above each
other or displaced by 180°).
If enough liquid (300 … 800 mm) remains in
the blind lower end of the tube, the portion of
the signal that penetrates the liquid and re-
Optimum connection to the bypass tube
flects from the tube bottom is sufficiently
damped - the sensor can then easily distinguish it from the echo of the liquid surface. In
cases where there is not enough liquid at the
bottom of the tube, a deflector situated there
will carry out the same function. It deflects
signals that reach the tube bottom into the
standard connection opening.
Welding beads too large
16 VEGAPULS 43 – 4 … 20 mA
26626-EN-041227
Mounting and installation
Tube connection protrudes
Additional connection in the bypass tube in one plane
Use of guide tubes
In case of very rough inner surfaces in existing bypass tubes (e.g. due to corrosion),
large connecting tube openings, as well as
bypass tubes with more than 100 mm inner
diameter, the use of a guide tube inside the
existing bypass tube is recommended. This
reduces the noise level and increases measurement reliability considerably. The flange of
the guide tube can be easily mounted as a
sandwich flange between vessel and sensor
flange.
Guide tube
Guide tube in existing surge or bypass tubes
To increase the min. distance, the guide tube
can project out of the surge or bypass tube.
This can be done by welding a flat welding
flange on the outside of the extended guide
tube. In both cases, an appropriate breather
hole is necessary.
Extended guide tube
26626-EN-041227
VEGAPULS 43 – 4 … 20 mA 17
Mounting and installation
Seals on tube connections and tube extensions
Microwaves are very sensitive to gaps in
flange connections. If connections are made
without proper care, distinct false echoes as
well as increased signal noise can result.
Observe the following points:
• The applied seal should correspond to the
tube inner diameter.
• If possible, conductive seals such as conductive PTFE or graphite should be used.
• There should be as few seal positions as
possible in the guide tube.
Flange connections on bypass tubes
Adhesive products
With non-adhesive or slightly adhesive products, use a surge pipe with a nominal width of
e.g. 50 mm. VEGAPULS 43 radar sensors
with 26 GHz technology are for the most part
insensitive to buildup in the measuring tube.
Nevertheless, buildup should not block the
measuring tube.
For products with somewhat heavier buildup,
the use of a DN 80 to max. DN 100 standpipe
or surge pipe can make measurement possible despite buildup. But with extremely adhesive products, measurement in a standpipe
is not possible at all.
Standpipe measurement of inhomogeneous products
ø 5...15
homogeneous
liquids
inhomogeneous liquids
Openings in a surge pipe for mixing of inhomogeneous products
If you want to measure inhomogeneous or
stratified products in a surge pipe, it must
have holes, elongated holes or slots. These
openings ensure that the liquid is mixed and
corresponds to the liquid in the vessel.
The more inhomogeneous the measured
product, the closer the openings should be
spaced.
Due to radar signal polarisation, the holes or
slots must be positioned in two rows offset
by 180°. The radar sensor must then be
mounted so that the type label of the sensor
is aligned with the rows of holes.
Every wider slot causes a false echo. The
slots should therefore not exceed a width of
10 mm in order to keep the signal noise level
to a minimum. Round slot ends are better
than rectangular ones.
slightly inhomogeneous
liquids
ø 5...15
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18 VEGAPULS 43 – 4 … 20 mA
Mounting and installation
Type label
ø 5...15
Row of holes in one axis with the type label
Surge pipe with ball valve
If a ball valve is mounted in the surge pipe,
maintenance and servicing can be carried
out without opening the vessel (e.g. if it contains liquid gas or toxic products).
Ball valve
> 300 mm
Vent hole
ø50
Deflector
Tube antenna system with ball valve cutoff in measuring tube
A prerequisite for trouble-free operation is a
ball valve throat that corresponds to the pipe
diameter and provides a flush surface with
the pipe inner wall. The valve must not have
any rough edges or constrictions in its channel. The distance to the sensor flange should
be at least 300 mm.
Guidelines for standpipe construction
The radar sensors with a DN 50 flange only
form a functioning measuring system in conjunction with a measuring tube.
The measuring pipe must be smooth inside
(average roughness Rz ≤ 30). Use stainless
steel tubing (drawn or welded lengthwise) for
construction of the measuring pipe. Extend
the measuring pipe to the required length
with weld-on flanges or with connecting
sleeves. Make sure that no shoulders or
projections are created during welding. Before welding, join pipe and flange with their
inner surfaces flush and exactly fitting.
Avoid welding through the pipe wall. The pipe
must remain smooth inside. Roughness or
welding beads on the inner surfaces must be
carefully removed and burnished, as they
cause false echoes and encourage product
adhesion.
If the vessel contains agitated products,
fasten the measuring pipe to the vessel bottom. Provide additional fastenings for longer
measuring pipes.
In products with lower dielectric values (< 4),
a part of the radar signal penetrates the
medium. If the vessel is nearly empty, echoes
are generated by both the product and the
vessel bottom. The echo from the vessel
bottom can in some cases be stronger than
the echo from the product surface. If a deflector is installed below the open end of the
measuring tube, the radar signals are scattered and prevented from reaching the vessel bottom. This ensures that, in nearly empty
vessels or with products of low dielectric
value, the product delivers a more distinct
echo than the vessel bottom.
Due to the deflector, the useful echo (and
thus the measured value) remains clearly
detectable in a nearly empty vessel, and the
0 % level can be reliably measured.
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VEGAPULS 43 – 4 … 20 mA 19
Mounting and installation
0 %
The standpipe or surge pipe can be
equipped with a quadrant pipe at its end
instead of a deflector. The quadrant pipe
reflects the radar signals that penetrate the
medium diffusely to the side and diminishes
strong echoes from the tube end or the vessel bottom.
Flange
DN 100
Deburr the
holes
150…500
Connecting
sleeve
Welding neck
flanges
Deflector
0 %
Quadrant pipe on the bypass tube end
Welding of the smooth
welding flange
100 %
ø 95
2
5…10
Welding of the connecting sleeves
0,0…0,4
Quadrant pipe on the standpipe end
3,6
Welding of the welding
neck flanges
3,6
1,5…2
0,0…0,4
ø 100,8
Meas. pipe fastening
0 %
~45û
Vessel
bottom
20 VEGAPULS 43 – 4 … 20 mA
26626-EN-041227
Mounting and installation
3.4 False echoes
The radar sensor must be installed at a location where no installations or inflowing material
cross the radar impulses. The following examples and instructions show the most frequent measuring problems and how to avoid
them.
Vessel protrusions
Vessel forms with flat protrusions can make
measurement very difficult due to their strong
false echoes. Baffles mounted above these
flat protrusions scatter the false echoes and
guarantee a reliable measurement.
Correct Incorrect
Vessel protrusions (ledge)
Intake pipes, i.e. for the mixing of materials with a flat surface directed towards the sensor - should be covered with an angled baffle
that scatters false echoes.
Vessel installations
Vessel installations, such as e.g. ladders,
often cause false echoes. Make sure when
planning your measuring location that the
radar signals have free access to the measured product.
Correct Incorrect
Ladder
Vessel installations
Ladder
Struts
Struts, like other vessel installations, can
cause strong false echoes that are superimposed on the useful echoes. Small baffles
effectively prevent a direct false echo reception. These false echoes are scattered and
diffused in the surrounding space and are
then filtered out as "echo noise“ by the measuring electronics.
Correct Incorrect
Correct Incorrect
Shields
Struts
Vessel protrusions (intake pipe)
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