VEGA PULS51K User Manual
Operating Instructions
VEGAPULS 51K … 54K
®
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 ............................................................. 5
1.3 Adjustment ............................................................................ 6
2 Types and v ersions ................................................................... 8
2.1 Overvie w .............................................................................. 8
2.2 Antennas ............................................................................. 10
3 Mo unting and in stalla tion ..................................................... 11
3.1 General installation instructions ........................................ 11
3.2 Measurement of liquids ..................................................... 12
3.3 Measurement in standpipe (surge or bypass tube) ...... 14
3.4 False echoes ...................................................................... 21
3.5 Common installation mistakes ........................................... 23
Contents
4 Electrical connection .............................................................. 25
4.1 Connection and connection cable .................................... 25
4.2 Connecting the sensor ...................................................... 27
4.3 Connecting 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
6.2 Error codes ........................................................................ 50
2 VEGAPULS 51K … 54K
21750-EN-031222
Contents
7 Technic al data .......................................................................... 51
7.1 Technical data ..................................................................... 51
7.2 Approvals ........................................................................... 58
7.3 Dimensions ......................................................................... 59
Supplement ..................................................................................... 63
Safet y Manual ................................................................................. 63
1 General ............................................................................... 63
1.1 Validity ................................................................................. 63
1.2 Area of application ............................................................... 63
1.3 Relevant standards ............................................................. 63
1.4 Determination of safety-related characteristics.................. 64
2 Planning .............................................................................. 65
2.1 Low demand mode ............................................................... 65
2.2 High demand or continuous mode ....................................... 65
2.3 General ................................................................................ 65
3 Set-up ................................................................................. 66
3.1 Mounting and installation ..................................................... 66
3.2 Adjustment instructions and parameter adjustment ........... 66
3.3 Configuration of the processing unit ................................... 66
4 Reaction during operation and in case of failure ............. 67
5 Recurring function test ....................................................... 67
6 Safety-related characteristics ........................................... 68
SIL declaration of conformity .................................................... 69
CE declaration of conformity ..................................................... 70
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.
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VEGAPULS 51K … 54K 3
1 Product description
Product description
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 5.8 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.
Meas.
distance
1 ns
278 ns
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.
tt
Time transformation
Hence, it is possible for the radar sensors to
process the slow-motion pictures of the sensor environment precisely and in detail in
cycles of 0.5 to 1 second without using timeconsuming frequency analysis (e.g. FMCW,
required by other radar techniques).
Virtually all products can be measured
Radar signals display physical properties
similar to those of visible light. According to
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 impulse 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.
4 VEGAPULS 51K … 54K
the quantum theory, they propagate through
empty space. Hence, they are not dependent 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.
21750-EN-031222
Product description
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 sufficiently (note: air has a dielectric constant ε
1). Signal reflectivity grows stronger with
r
r
increasing conductivity or increasing dielectric constant of the product. Hence, nearly all
substances can be measured.
%
50
40
30
20
10
5 %
5
0
2
0
25 %
4 6 8 12 14 16 18
10
40 %
20
ε
r
Reflected radar power dependent on the dielectric
constant of the measured product
With standard flanges of DN 50 to DN 250,
ANSI 2“ up to ANSI 10“ 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 and have a long useful life.
%
0,03
0,02
0,01
0
100 500 1000 1300 ˚C
0
0,018 %
0,023 %
Temperature influence: Temperature error absolutely
zero (e.g. at 500°C 0.018 %)
of
%
10
5
0
0
0,29 %
10
20 30 40 60
1,44 %
50
2,8 %
70 80 90 110 120 130 140
100
Pressure influence: Error with pressure increase very
low (e.g. at 50 bar 1.44 %)
VEGAPULS 50 sensors allow radar level
measurement in plants where it was hitherto
unthinkable because of high costs.
1.2 Application features
Applications
• level measurement of any liquid, limited in
solids.
• measurement also in vacuum
• all slightly conductive materials and all
substances with a dielectric constant > 2.0
can be measured
• measuring range 0 … 20 m.
Two-wire technology
• power supply and output signal on one
two-wire cable (Loop powered)
• 4 … 20 mA output signal or HART® output
signal.
3,89 %
bar
Continuous and accurate
Unaffected by temperature, pressure and
atmosphere content, VEGAPULS radar sensors measure quickly, accurately and continuously the levels of widely varying
products.
Rugged and abrasionproof
• non-contact
• high-resistance materials
Exact and reliable
• accuracy 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 40 bar
and product temperatures up to 200 °C.
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VEGAPULS 51K … 54K 5
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 from PLC level with the PC
Approvals
• CENELEC, ATEX, PTB, FM, CSA, ABS,
LRS, GL, LR, FCC.
1.3 Adjustment
Every measurement setup 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® handheld
Product description
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)
The PC can be connected at any location in
the system or directly to the signal cable. It is
connected by means of the two-wire 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.
Adjustment with the PC
The set-up and adjustment of the radar sensors is generally done on the PC with the
adjustment software PACT
ware
TM.
The pro-
2
PLC
2
gram leads quickly through the adjustment
and parameter setting by means of pictures,
graphics and process visualisations.
Adjustment with the PC on the 4 … 20 mA signal and
supply cable or directly on the sensor (figure: a twowire sensor)
6 VEGAPULS 51K … 54K
21750-EN-031222
Product description
Adjustment with the adjustment module
MINICOM
With the small (3.2 cm x 6.7 cm) 6-key adjustment module with display, the adjustment
is 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
+
Tank 1
-
m (d)
12.345
OK
2
4 ... 20 mA
ESC
+
-
OK
Adjustment with the HART® handheld
Series 50 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 adjustment jacks on the sensor.
2
4 ...20 mA
2
®
ESC
+
Tank 1
-
m (d)
12.345
OK
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.
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VEGAPULS 51K … 54K 7
2 Types and versions
Types and versions
2.1 Overview
VEGAPULS series 50 sensors are a newly
developed generation of very compact, small
radar sensors. With modest space requirements, they were developed for short measuring distances of 0 … 20 m and for
standard applications such as storage tanks
and buffer tanks, but also for process vessels.
Due to their small housing dimensions and
process connections, the compact sensors
do your level monitoring inconspicuously, and
above all, at reasonable cost. With their integrated display and remarkable intelligence,
they bring the advantages of radar level
measurement to applications where previously, due to high cost, the advantages of
non-contact measurement had to be foregone.
VEGAPULS 50 radar sensors utilise two-wire
technology perfectly. The supply voltage and
the output signal are transmitted via one twowire cable. They provide an analogue
4 … 20 mA output signal as output or measuring signal.
VEGAPULS 51/52
VEGAPULS 54
(pipe antenna/
standpipe)
VEGAPULS 53
VEGAPULS 54
(pipe antenna/
standpipe)
8 VEGAPULS 51K … 54K
21750-EN-031222
Types and versions
Features
General features
• Application preferably for liquids in storage tanks.
• Measuring range 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
VEGAPULS …
51K 52K 53K 54K
Signal output
- active (4 … 20 mA) • • • •
- passive (4 … 20 mA) • • • •
Voltage output
- two-wire technology (power
supply and signal output
via one two-wire cable) • • • •
- four-wire technology (power
supply separate from the signal
cable) • • • •
Process fitting
- G1½ A; 1½“ NPT • • – –
- DN 50; ANSI 2“ – – • •
- DN 80; ANSI 3“ – – • •
- DN 100; ANSI 4“ – – • •
- DN 150; ANSI 6“ – – • •
Adjustment
-PC • • • •
- adjustment module in the sensor • • • •
- adjustment module in external
indicating instrument • • • •
- HART® handheld • • • •
Antenna material
- PP/PVDF • – – –
- PPS/StSt • – – –
- PTFE/PVDF – • – –
- PTFE/StSt – • – –
- PTFE – – • –
- StSt/PTFE – – – •
- Hastelloy C22/PTFE – – – •
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VEGAPULS 51K … 54K 9
Types and versions
2.2 Antennas
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 geometrical form determines focal properties and sensitivity - the
same way it determines the sensitivity of a
unidirectional microphone.
Four antenna systems are available for different applications and process requirements.
Beside having its own unique focusing characteristics, each system differs in its chemical and physical properties.
Rod antenna
Rod antennas with high chemical resistance require only the
very smallest flange diameters
(DN 50). The antenna rod and
the wetted flange parts are
made of PTFE, PP or PPS so
that the rod antenna can be
easily cleaned and provide
resistance to condensation.
The rod antenna is suitable for
pressures up to 16 bar and
temperatures up to 150 °C.
Horn antenna
Horn antennas are well suited
for most applications. They
focus the radar signals very
well. Manufactured of 1.4571
(StSt) or Hastelloy C22, they
are very rugged and are
physically as well as chemically resistant. They are suitable for pressures up to
40 bar and for product temperatures up to 150 °C.
Pipe antenna
The pipe antennas on surge
or bypass tubes only form a
complete antenna system in
conjunction with a measuring
tube (which can also be
curved). Pipe antennas are
especially suitable for products with strong flow or turbulence, or products with low
dielectric constant.
The antenna is available with
or without a horn. Versions
with horn are characterised
by a very high antenna gain.
High measurement reliability
can thus be achieved even in products with
very poor reflective properties.
The measuring tube acts as a
conductor for radar signals.
The running period of the radar
signals changes in the tube and
depends on the tube diameter.
The tube inner diameter must
be programmed in the sensor
so that it can take the altered
running time into account and
deliver accurate level signals.
10 VEGAPULS 51K … 54K
21750-EN-031222
Mounting and installation
3 Mounting and installation
3.1 General installation instructions
Keep in mind that in measuring environments
where the medium can reach the sensor
Measuring range
The reference plane for the measuring range
flange, buildup may form on the antenna and
later cause measurement errors.
of the sensor is the lower edge of the flange
or the seal shoulder of the thread
(VEGAPULS 51, 52). The measuring range is
0 … 20 m. When measuring in a surge or
Note: The series 50 sensors are suitable for
measurement of solids only under certain
conditions.
bypass tube (pipe antenna), the max. measuring distance is reduced.
full
Reference plane
max. filling
Measuring range (operating range) and max. measuring distance
Note: Use of the sensors for applications with solids is limited.
False echoes
empty
max.
4 m
Meas. range
16 m
max. meas. distance 20 m
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 taking a direct path back to the
radar sensor. The signals are then so low-
Interfering 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.
max.
max.
Round profiles diffuse radar signals
Profiles with flat interfering surfaces cause large
false signals
Cover smooth interfering surfaces with deflectors
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VEGAPULS 51K … 54K 11
Mounting and installation
Emission cone and false reflections
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 causes a reflection of 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 that 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.
Make sure the sensor axis is perpendicular
to the product surface and avoid, if possible,
vessel installations (e.g. pipes and struts)
within the 50 % area of the emission cone.
The illustrations of the emission cone are
simplified and represent only the main beam
- a number of weaker beams also exists.
Under difficult measuring conditions, the
antenna alignment must be selected with the
objective of reaching the lowest possible
echo intensity. Only giving attention to the
size of the useful echo is not adequate when
measuring conditions are unfavourable.
In difficult measuring environments, 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 PACTwareTM on
the PC, you can have a look at the echo image and optimise the mounting location (see
chapter „5.2 Adjustment with the PC – Sensor
optimisation – Echo curve“).
If possible, provide a „clear view" of 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 it is free of
obstructions.
3.2 Measurement of liquids
Flange antennas
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 antenna should
always protrude out of the flange pipe.
If the DIN socket piece is longer, make sure
that the horn antenna does not appear in the
socket opening.Better results are achieved
when the antenna protrudes at least 10 mm
out of the socket.
Reference plane
> 10 mm
Mounting on DIN socket piece
In vessels with dished or rounded tops, the
antenna length should at least correspond to
the length of the longer sockets.
Vessel center or
symmetric axis
> 10 mm
Mounting on a dished vessel top
12 VEGAPULS 51K … 54K
21750-EN-031222
Mounting and installation
On dished tank ends, please do not mount
the instrument in the centre or close to the
vessel wall, but approx. ½ vessel radius from
the centre or from the vessel wall.
Dished tank ends can act as paraboloidal
reflectors. If the radar sensor is placed in the
focal point of the parabolic tank, the radar
sensor receives amplified false echoes. The
radar sensor should be mounted outside the
focal point. Parabolically amplified echoes are
thereby avoided.
Vessel center or
symmetric axis
Reference plane
½ vessel radius
Mounting on round vessel tops
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.
Rod antenna
Rod antenna on DIN socket piece
The PTFE (Teflon) rod antenna is well suited
to chemically aggressive products such as
lyes and acids. Applications in the food
processing industry with aseptic vessel
conditions require nonreactive measuring
systems and very small vessel openings.
The Teflon rod antenna is not only
nonreactive, but can be mounted in very
small vessel openings (50 mm or 1½“ thread
holes).
For measurements of liquids, the Teflon rod
antenna is mounted on a straight DIN socket
piece. The socket however must not be
longer than 150 mm (when using the longer
antenna, not longer than 250 mm). The rod
antenna is available in flange sizes of DN 50,
DN 80 and DN 100.
≤ 50 mm, 100 mm or
250 mm
Rod antenna on DIN socket piece
Rod antenna directly on the vessel opening
Reference plane
Opening
ø 50 mm
Mounting directly on the flat vessel top
Rod antenna directly on the vessel opening
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VEGAPULS 51K … 54K 13
Mounting and installation
As an alternative to socket mounting, the rod
antenna can also be mounted in round vessel
openings (threaded holes).
Rod antennas are available for the following
vessel openings: 1½“ NPT, DN 50 up to
DN 150. Keep in mind that the PTFE rod
antenna can only be subjected to very small
mechanical loads. If it is subjected to bending forces, deformation or even breakage will
occur.
Rod antenna with thread
When mounting the sensors with 1½“
screwed process connection in a socket
piece, the max. socket length must be observed. The permissible socket length depends on the antenna rod and is 50 mm,
100 mm or 250 mm, see also chapter „8.3
Dimensions“.
Reference plane
≤ 50 mm or 100 mm or
250 mm
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
even when the product surface is very turbulent, and vessel installations can cause no
false echoes.
Due to the concentration of radar signals in
the measuring tube, even products with small
dielectric constants (ε
reliably measured in surge or bypass tubes.
Please observe the following installation directions.
Surge pipe welded
to the tank
= 1.6 up to 3) can be
r
Surge pipe in the
socket piece
Type label
max.
Rod antenna with thread on 1½“ socket
without deflector
Pipe antenna systems in the tank
Vent hole
ø 5 … 10 mm
min.
with deflector
Surge pipes or bypass tubes which are
open at the bottom must extend over the full
measuring range (i.e. down to 0% level), as
Rod antenna with thread on 1½“ thread hole
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.
14 VEGAPULS 51K … 54K
21750-EN-031222
Mounting and installation
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 can be installed in
a bypass tube outside the vessel.
With measurement in a surge or bypass
tube, the max. measuring range decreases
by 5 … 20 % (e.g. DN 50: 16 m instead of
20 m and with DN 100 only 19 m instead of
20 m) due to the change of running time of
the radar signal.
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
> 500 mm
100 %
100 %
75 %
0 %
Extended bypass tube on a vessel with turbulent
product movement
Type label
> 500 mm
100 %
0 %
Tube flange system as bypass tube
When mounting a VEGAPULS 52 on a bypass tube (e.g. on a previous floating or
0 %
300 ... 800 mm
displacer unit), the radar sensor should be
placed approx. 500 mm or more from the
Tube flange system as bypass tube
upper tube connection. If the tube has a
rough inner surface, the use of an additional
measuring tube (tube in tube) is recommended, as poor surface quality of the measuring tube hampers radar measurement
through an excessively high „noise level“.
For products with small dielectric values
(< 4), the bypass tube should extend below
the lower tube connection. Products with
small dielectric constants are partly penetrated by the radar signals, which could
allow the tube bottom to deliver a stronger
echo than the product surface (when the
bypass tube is nearly empty). By extending
the lower end of the bypass tube, enough
liquid remains in the tube even when the
vessel i.e. emptied.
21750-EN-031222
VEGAPULS 51K … 54K 15
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 reflects 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.
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.
• 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°).
Mounting and installation
Welding beads too large
Tube connection protrudes
Additional connection in the bypass tube in one plane
Adhesive products
With adhesive products, a surge pipe with a
larger inner diameter should be used. For
non-adhesive products, the best and most
inexpensive solution is a measurement tube
with a diameter of 50 mm. For slightly adhesive products, use a surge pipe with a nomi-
Optimum connection to the bypass tube
16 VEGAPULS 51K … 54K
nal diameter of 100 mm or 150 mm to prevent
buildup from causing measurement errors.
Measurement of extremely adhesive products in a standpipe is not possible.
21750-EN-031222
Mounting and installation
DN 50
ø 50
Pipe antennas with DN 50, DN 80, DN 100 and
DN 150
DN 150
ø 150
Use of guide tubes
In case of very rough inner surfaces in existing bypass tubes (e.g. due to corrosion),
large connection 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 reliability considerably. The flange of the guide tube can
be easily mounted as a sandwich flange
between vessel and sensor flange.
To increase the min. distance, the guide tube
can project out of the surge or bypass tube.
For this purpose, a plain flange can be
welded at the required position on the outside of the extended guide tube. In both
cases, a breather hole must be provided.
Seals on tube connections and tube extensions
Extended guide tube
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.
Guide tube
Observe the following points:
• The seal used should correspond to the
tube inner diameter
• If possible, conductive seal made of materials such as conductive PTFE or graphite
should be used
• There should be as few seal positions as
possible in the guide tube.
Guide tube in existing surge or bypass tube
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VEGAPULS 51K … 54K 17
Flange connections on bypass tubes
Standpipe measurement of inhomogeneous products
Mounting and installation
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.
Type label
ø 5...10
homogeneous
liquids
ø 5...10
slightly inhomogeneous
liquids
VEGAPULS 54: Row of holes in one axis with the type
label
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
ø 5...10
to a minimum. Round slot ends are better
than rectangular ones.
inhomogeneous liquids
Openings in a surge pipe for mixing of inhomogeneous products
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Mounting and installation
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).
DN 50
Ball valve
Vent hole
ø50
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 constricted areas in its
channel. The distance to the sensor flange
should be at least 500 mm.
> 500 mm
Deflector
Guidelines for standpipe construction
Radar sensors for measurement on surge or
bypass tubes are used with G 1½ A screwon antenna or in the flange sizes DN 50,
DN 80, DN 100 and DN 150. The radar sensors with a DN 50 flange only forms a functioning measuring system when used in
conjunction with a measuring tube.
The illustration on the left shows the constructional features of a measuring tube (surge or
bypass tube) as exemplified by a radar
sensor with DN 50 flange.
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.
The following illustration shows the constructional features of a measuring tube as exemplified by a radar sensor with DN 100 flange.
If the vessel contains agitated products,
fasten the measuring pipe to the vessel bottom. Provide additional fastenings for longer
measuring pipes.
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Flange
DN 100
VEGAPULS 54
Mounting and installation
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.
Deburr the
holes
150…500
Connecting
sleeve
Welding neck
flanges
Deflector
0 %
Welding of the smooth
welding neck flanges
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.
100 %
ø 95
2
Welding of the connecting sleeves
5…10
The standpipe or surge pipe can be
equipped with a quadrant pipe at its end
instead of a deflector. This quadrant pipe
reflects the radar signals that penetrate the
0,0…0,4
medium diffusely to the side and diminishes
strong echoes from the tube end or the vessel bottom.
3,6
Welding of the welding
ø 100,8
~45˚
3,6
neck flanges
1,5…2
0,0…0,4
Meas. pipe fastening
Vessel
bottom
Quadrant pipe on the bypass tube end
0 %
0 %
Quadrant pipe on the standpipe end
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Mounting and installation
3.4 False echoes
The radar sensor must be be installed at a
location where no installations or inflowing
material cross the radar pulses. 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)
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 overlay the
useful echoes. Small baffles effectively prevent a direct reception of false echoes. These
false echoes are scattered and diffused in
the surrounding space and then filtered out
as "echo noise“ by the measuring electronics.
Intake pipes, i.e. for the mixing of materials with a flat surface directed towards the sensor - should be covered with an angled baffle
Correct Incorrect
that scatters false echoes.
Correct Incorrect
Shields
Struts
Vessel protrusions (intake pipe)
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Mounting and installation
;;
;;
;;
;;
;;
;;
;;
;;
;;
Inflowing material
Do not mount the instrument in or above the
filling stream. Make sure that you detect the
product surface and not the inflowing material.
Correct
Inflowing material
Incorrect
Buildup
If the sensor is mounted too close to the
vessel wall, product buildup and other deposits on the vessel wall cause false echoes.
Position the sensor at a sufficient distance
from the vessel wall. Please also note chapter
"3.1 General installation instructions“.
Correct
Incorrect
Strong product movements
Strong turbulence in the vessel, e.g. caused
by powerful stirrers or strong chemical reactions, can seriously interfere with the measurement. A surge or bypass tube (see
illustration) of sufficient size always enables
reliable and problem-free measurement even
if strong turbulence occurs in the vessel,
provided there is no product buildup in the
tube.
Correct
Strong product movements
Incorrect
100 %
75 %
0 %
Buildup
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