VEGA PULS45 User Manual
Operating Instructions
VEGAPULS 42, 44 and 45
®
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 ............................................................................ 6
2 Types and versions ................................................................... 8
2.1 Surve y ................................................................................... 8
2.2 Antennas............................................................................. 10
3 Mounting and installation ..................................................... 12
3.1 General installation instructions ........................................ 12
3.2 Measurement of liquids ..................................................... 14
3.3 Measurement in standpipe (surge or bypass tube) ...... 15
3.4 False echoes ...................................................................... 22
3.5 Common installation mistakes ........................................... 24
Contents
4 Electrical connection .............................................................. 27
4.1 Connection and connection cable .................................... 27
4.2 Connection of the sensor .................................................. 29
4.3 Connection of the external indicating instrument
VEGADIS 50 ....................................................................... 33
4.4 Configuration of measuring systems ............................... 34
5 Set-up ........................................................................................ 42
5.1 Adjustment media .............................................................. 42
5.2 Adjustment with PC ............................................................ 42
5.3 Adjustment with adjustment module MINICOM ............... 44
5.4 Adjustment with HART® handheld ................................... 50
6 Diagnostics............................................................................... 52
6.1 Simulation ............................................................................ 52
5.2 Error codes ........................................................................ 52
2 VEGAPULS 42, 44 and 45 – 4 … 20 mA
Contents
7 Technical data .......................................................................... 53
7.1 Technical data ..................................................................... 53
7.2 Approvals ........................................................................... 58
7.3 Dimensions ......................................................................... 59
Supplement..................................................................................... 62
Safet y Manual ................................................................................. 62
1 General ............................................................................... 62
1.1 Validity ................................................................................. 62
1.2 Area of application ............................................................... 62
1.3 Relevant standards ............................................................. 62
1.4 Determination of safety-related characteristics .................. 63
2 Planning .............................................................................. 64
2.1 Low demand mode ............................................................... 64
2.2 High demand or continuous mode ....................................... 64
2.3 General ................................................................................ 64
3 Set-u p ................................................................................. 65
3.1 Mounting and installation..................................................... 65
3.2 Adjustment instructions and parameter adjustment ........... 65
3.3 Configuration of the processing unit ................................... 65
4 Reaction during operation and in case of failure ............. 66
5 Recurring function test ....................................................... 66
6 Safety-related characteristics ........................................... 67
SIL declaration of conformity .................................................... 68
CE declaration of conformity..................................................... 69
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 VEGA
personnel.
VEGAPULS 42, 44 and 45 – 4 … 20 mA 3
1 Product description
Product description
VEGAPULS series 40 sensors are a newly
developed generation of extremely compact,
small radar sensors for accurate, high-resolution measurement. They are characterised
by very good focussing properties for applications in narrow spaces. With very modest
space requirements, they were developed
for measuring distances of 0 … 4 m/10 m/
20 m and are the right choice for standard
applications such as storage vessels, reservoirs and buffer tanks as well as process
tanks.
Due to small housing dimensions and process fittings, the compact sensors are an
unobstrusive, and most of all, very costeffective solution for your level measurement
applications. With the integrated display, they
enable high precision level measurements
and make accessible the advantages of noncontact measurement in applications where,
due to high cost, they previously couldn’t be
put into effect.
VEGAPULS 40 radar sensors are perfectly
suited 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 output signal
as output, i.e. measuring signal.
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.
Meas.
distance
emission - reflection - reception
The radar pulses are emitted by the antenna
1.1 Function
Radio detecting and ranging: Radar.
VEGAPULS radar sensors are used for noncontact and continuous distance measurement. The measured distance corresponds
to a filling height and is outputted as level.
4 VEGAPULS 42, 44 and 45 – 4 … 20 mA
system as pulse packets 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
Pulse sequence
Product description
VEGAPULS can achieve this through a special time transformation procedure which
spreads out the more than 3.6 million echo
images per second in a 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).
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 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.
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
increasing conductivity or increasing dielectric constant of the product. Hence, nearly all
substances can be measured.
r
r
%
50
40
30
20
10
5 %
5
0
2
0
25 %
4 6 8 12 14 16 18
10
Reflected radar power dependent on the dielectric
constant of the measured product
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 environ-
ments.
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.
Continuous and accurate
Unaffected by temperature, pressure and
atmosphere content, VEGAPULS radar sen-
sors measure quickly and accurately the
levels 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
of
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
40 %
20
ε
r
3,89 %
bar
VEGAPULS 42, 44 and 45 – 4 … 20 mA 5
Product description
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
can be measured
• measuring range 0 … 10 m (type 42).
measuring range 0 … 20 m (type 44).
measuring range 0 … 4 m (type 45).
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 40 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
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
TM.
ware
The pro-
2
4 ... 20 mA
2
Approvals
• CENELEC, ATEX, PTB, FM, CSA, ABS,
LRS, GL, LR, FCC.
Adjustment with the PC on the analogue 4 … 20 mA
signal and supply cable or directly on the sensor
(four-wire sensor)
6 VEGAPULS 42, 44 and 45 – 4 … 20 mA
Product description
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)
Adjustment with the adjustment module
MINICOM
With the small (3.2 cm x 6.7 cm) 6-key adjustment module with display, the adjustment
can 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
ESC
+
-
Tank 1
m (d)
12.345
OK
2
4 ... 20 mA
ESC
+
-
Tank 1
m (d)
12.345
OK
4
Adjustment with detachable adjustment module. The
adjustment module can be plugged into the radar
sensor or into the external indicating instrument
VEGADIS 50.
VEGAPULS 42, 44 and 45 – 4 … 20 mA 7
Product description, types and versions
HART Communicator
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
of the handheld.
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
®
justment jacks on the sensor.
®
standard menus
handheld into the ad-
2
4 ... 20 mA
2
2 Types and ver sions
2.1 Survey
®
Series 40 sensors are manufactured in three
basic versions as VEGAPULS 42, 44 and 45
VEGAPULS 42 sensors are distinguished by
a G 1½ A or 1½“ NPT threaded mounting
boss as process connection. These sensors
are equipped in standard versions with a
ø 40 mm horn antenna.
VEGAPULS 44 sensors typically have DIN or
ANSI flanges as process connection. In
standard version they are manufactured with
DN 50, 80, 100 and 150, as well as with ANSI
2“, 3“, 4“ and 6“. The bigger flanges are
equipped with respectively bigger antenna
horns (ø 48, 75 and 95 mm).
Generally speaking: The bigger the antenna
horn, the better the focussing characteristics
and the better the antenna gain. This ensures
that even a weak level echo will be reliably
detected as level echo.
VEGAPULS 45 sensors are distinguished by
a measuring tube up to 4 m length. These
sensors are used if increased accuracy is
required or if liquids with very low dielectric
values must be detected, such as e.g. liquid
gas.
HART® handheld on the 4 … 20 mA signal cable
8 VEGAPULS 42, 44 and 45 – 4 … 20 mA
Types and versions
Survey
General features
• Application preferably for liquids in storage tanks and process vessels with increased
accuracy requirement.
• Measuring range 0 … 4 m, 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
PS42XXD… PS44XXD… PS45XXXD…
Signal output
- active (4 … 20 mA) • • •
- passive (4 … 20 mA, loop powered) • • •
Antenna
- horn antenna • • –
- pipe antenna
1) 1)
•
Process connection
- G 1½ 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 • • •
Measuring range 0 … 4 m
- ø 40 mm horn 0 … 10 m – (dependent on
- ø 48 mm horn 0 … 15 m 0 … 15 m tube length)
- ø 75 mm horn 0 … 20 m 0 … 20 m
- ø 95 mm horn 0 … 20 m 0 … 20 m
1)
If the sensor is mounted on a standpipe or bypass tube, a pipe antenna is created. The tube inner diameter
should be between 40 mm and 80 mm.
VEGAPULS 42, 44 and 45 – 4 … 20 mA 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.
For different applications and process requirements, series 40 sensors are manufactured in three basic versions: as VEGAPULS
42, VEGAPULS 44 and VEGAPULS 45.
VEGAPULS 42 sensors are distinguished by
a G 1½
A or 1½“ NPT threaded mounting
boss as process connection. These sensors
are equipped in standard versions with a
ø 40 mm horn antenna.
VEGAPULS 44 sensors typically have DIN or
ANSI flanges as process connection. In
standard versions, they are manufactured
with DN 50, 80, 100 and 150, as well as with
ANSI 2“, 3“, 4“ and 6“. The bigger flanges are
equipped with respectively bigger antenna
horns (ø 48, 75 and 95 mm).
Generally speaking: The bigger the antenna
horn, the better the focussing characteristics
and the better the antenna gain. This ensures
that even a weak level echo will be reliably
detected as a level echo.
VEGAPULS 45 sensors are distinguished by
an integrated measuring tube. The measuring tube serves as a waveguide for the radar
signals and allows no transmitting energy to
be lost. The entire transmission energy returns as reflection energy, enabling reliable
detection also of products with very weak
reflection characteristics such as e.g. light
petrol, liquid gas etc. with
1.4 … 2.0. Viscous or adhesive products
ε
-values of
r
cannot be measured with VEGAPULS 45.
Horn antennas
Horn antennas focus the
radar signals very well.
Made of 1.4435 (stainless
steel) or Hastelloy C22, they
are very rugged, and physically as well as chemically
resistant. They are suitable
for pressures up to 40 bar
and for product tempera-
VEGAPULS 42
tures up to 150 °C. The horn
diameters determine the
focussing of the radar signals. The bigger the horn
diameter (40, 48, 75,
95 mm), the bigger the
antenna gain. The antenna
gain represents the ratio of
transmitted energy to received echo energy.
VEGAPULS 44
10 VEGAPULS 42, 44 and 45 – 4 … 20 mA
Types and versions
Pipe antennas
Pipe antennas consisting of horn antenna
and standpipe or bypass tube
Only in conjunction with a
measuring tube, i.e. with a
surge or bypass tube (which
can also be curved), do horn
antennas form a complete
antenna system. The measuring tube acts as a conductor for the radar signals. The
running time of the radar
signals changes in the tube
and depends on the tube
diameter. Therefore, the
sensor must be informed
about the tube inner diameter so that the change in the
running time can be taken
into account and accurate
level signals outputted. Pipe
antennas are especially
suitable for very agitated
products or for products
with very small dielectric
constant.
The antennas are characterised by a very high antenna
gain. High reliability can be
achieved even with products
having poor reflective properties.
VEGAPULS 42
Pipe antenna
consisting of horn
antenna and
bypass tube
VEGAPULS 44
Pipe antenna
consisting of horn
antenna and
bypass tube
VEGAPULS 45
with thread,
pipe antenna
integrated in the
sensor
VEGAPULS 45
with flange,
pipe antenna
integrated in the
sensor
Pipe antenna integrated in the sensor
VEGAPULS series 45 was a further development of the concept of VEGAPULS 42 and 44
sensors being used in conjunction with surge
or bypass tubes. This sensor was designed
with an optimised measuring tube up to 4 m
long which enables high-precision level
measurement also of products with very
small dielectric constants ε
liquid gas).
VEGAPULS 42, 44 and 45 – 4 … 20 mA 11
= 1.4 … 1.8 (e.g.
r
3 Mounting and installation
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
of the sensor is the lower edge of the flange
or the seal shoulder of the thread. For measurements in surge or bypass tubes with
VEGAPULS 45 the max. distance depends
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.
on the tube length.
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
full
empty
max.
Meas. range
max. meas. distance 20 m (type 45: 4 m)
min.
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.
max.
max.
min.
Round profiles diffuse radar signals
Profiles with smooth interfering surfaces cause large
false signals
Cover smooth interfering surfaces with deflectors
12 VEGAPULS 42, 44 and 45 – 4 … 20 mA
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 avoid
vessel installations (e.g. pipes and struts)
within the 50% 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 should be oriented so that the lowest
possible false echo values appear. 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.
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
ware
TM
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“).
VEGAPULS 42, 44 and 45 – 4 … 20 mA 13
Mounting and installation
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 must
always protrude out of the flange pipe.
If the DIN socket piece is longer, please
make sure that the horn antenna still protrudes out of the socket.
Reference plane
< 135 mm (DN 50)
< 210 mm (DN 80)
< 310 mm (DN 100, DN 150)
Mounting on DIN socket piece
In vessel with dished or rounded tops, the
antenna length should at least correspond to
the length of the socket.
Vessel center or
symmetric axis
On dished vessel tops, 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 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.
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.
<135…310mm
(250…425mm
with antenna
extension)
Mounting directly on flat vessel top
Mounting on a dished vessel top; max. socket length
dependent on the flange size and possibly on the
antenna extension (see „7.3 Dimensions“).
14 VEGAPULS 42, 44 and 45 – 4 … 20 mA
Reference plane
Mounting and installation
Screwed antenna
The screwed antenna is used mainly on very
small vessels. The antenna fits into even the
smallest vessel connection openings (1
socket). The socket must not be longer than
135 mm (when used with a longer antenna,
not longer than 250 mm).
Reference plane
≤ 135 mm
Screwed antenna on 1½“ mounting boss
≤ 250 mm
1
/2“
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.
Also, 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. Note the following instructions.
Surge pipe welded
to the tank
Type label
= 1.6 up to
r
Surge pipe in the
socket piece
maxmax
Screwed antenna with antenna extension on socket
piece
Vent hole
ø 5 … 10 mm
As an alternative to socket mounting, the
screwed antenna can also be mounted in
round vessel openings (threaded holes).
min
without deflector
Pipe antenna system in the tank
with deflector
min
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 corre-
Rod antenna directly on vessel opening
VEGAPULS 42, 44 and 45 – 4 … 20 mA 15
spond to the size of the antenna horn.
Make sure the required upper vent hole in
the surge pipe is aligned with the sensor
type label.
Mounting and installation
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 %
0 %
Tube flange system as bypass tube
> 300 mm
100 %
75 %
0 %
Extended bypass tube on a vessel with turbulent
product movements
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.
When mounting a VEGAPULS 42 or 44 sen-
Type label
sor on a bypass tube (e.g. on a previous
floating or displacer unit), the radar sensor
should be placed approx. 300 mm or more
from the max. level.
16 VEGAPULS 42, 44 and 45 – 4 … 20 mA
100 %
0 %
Tube flange system as bypass tube
> 300 mm
300 ... 800 mm
Mounting and installation
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 tube
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°).
Welding beads too large
Tube connection protrudes
Additional connection in the bypass tube in one plane
Use of guide tubes
(VEGAPULS 44)
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
Optimum connection to the bypass tube
VEGAPULS 42, 44 and 45 – 4 … 20 mA 17
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.
Guide tube
Guide tube in existing surge or bypass tubes
To increase the min. distance, the guide tube
can protrude 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 guide tube. In both cases, a
breather hole must be provided.
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
In non-adhesive or slightly adhesive products, use a surge pipe with a nominal width of
e.g. 50 mm. VEGAPULS 42 and 44 radar
sensors with 26 GHz technology are for the
most part insensitive to buildup in the measuring tube. However, buildup should not
block the measuring tube.
For products with heavier buildup, the use of
a DN 80 to max. DN 100 standpipe or surge
pipe can make the measurement possible
despite buildup. With products that are ex-
Extended guide tube
18 VEGAPULS 42, 44 and 45 – 4 … 20 mA
tremely adhesive, measurement in a standpipe is not possible at all.
Mounting and installation
VEGAPULS 45 with integrated measuring tube
VEGAPULS 45 sensor version was especially developed for measuring tube applications and is supplied complete with a 27 mm
measuring tube. With a measuring tube
length up to 4 m, this sensor version can be
used, e.g. in existing standpipes.
max
min
VEGAPULS 45 with integrated measuring tube in the
vessel or in an existing bypass tube
VEGAPULS 45 with integrated measuring tube (surge
pipe) measures between heating spirals
Standpipe measurement of inhomogeneous products
Note:
ø 5...15
VEGAPULS 45 sensors with an integrated
measuring tube are provided with a screwed
process connection or a flange connection.
For sensors with screwed thread as process
connection, make sure that during screwing
in the entire sensor turns, i.e. also the sensor
housing. The sensor housing is fastened with
a clamping connection to the measuring tube.
This sensor housing must not be turned with
respect to measuring tube or even loosened.
Otherwise, the radar signal coupling would
homogeneous
liquids
slightly inhomogeneous
liquids
ø 5...15
be destroyed and the sensor would no
longer function.
inhomogeneous liquids
Openings in a surge pipe for mixing of inhomogeneous products
VEGAPULS 42, 44 and 45 – 4 … 20 mA 19
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.
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.
Type label
ø 5...15
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
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. The valve must not have rough
edges or narrow areas in its channel. The
distance to the sensor flange should be at
least 300 mm.
> 300 mm
Deflector
VEGAPULS 44: Row of holes in one axis with the type
label
20 VEGAPULS 42, 44 and 45 – 4 … 20 mA
Mounting and installation
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 form a functioning measuring system in conjunction with a measuring
tube.
On the left you see the constructional features of a measuring pipe (surge or bypass
tube) as exemplified by a radar sensor with a
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.
In the following illustration you see the constructional features of a measuring pipe as
exemplified by a radar sensor with a DN 100
flange.
If the vessel contains agitated products,
fasten the measuring pipe to the vessel bottom. Provide additional fastenings for longer
measuring pipes.
Flange DN
100
Deburr the
holes
150…500
Connecting
sleeve
Welding neck
flanges
Deflector
0 %
VEGAPULS 44
Welding of the smooth
welding neck flanges
100 %
ø 95
2
ø 100,8
~45˚
Welding of the connecting sleeves
5…10
0,0…0,4
3,6
Welding of the welding
neck flange
3,6
1,5…2
0,0…0,4
Meas. pipe fastening
Vessel
bottom
VEGAPULS 42, 44 and 45 – 4 … 20 mA 21
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.
Due to the deflector, the useful signal and
meas. value in the nearly empty vessel are
distinct and clear - the 0 % level can thus be
reliably measured.
Instead of a deflector, the standpipe or surge
pipe can be equipped with a quadrant pipe
at the end. This reflects the radar signals that
penetrate the medium diffusely to the side
and diminishes strong echoes from the tube
end or the vessel bottom.
3.4 False echoes
The radar sensor must 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
0 %
Vessel protrusions (ledge)
Intake pipes, i.e. for the mixing of materials with a flat surface directed towards the sen-
Quadrant pipe on the bypass tube end
sor - should be covered with an angled baffle
that scatters false echoes.
Correct Incorrect
0 %
Quadrant pipe on the standpipe end
Vessel protrusions (intake pipe)
22 VEGAPULS 42, 44 and 45 – 4 … 20 mA
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