VEGA PULS56 User Manual

Operating Instructions
VEGAPULS 56 Profibus PA
Level and Pressure
Contents
Safety information ........................................................................ 3
Note Ex area ................................................................................ 3
1.1 Function................................................................................. 4
1.2 Application features ............................................................. 6
1.3 Profibus output signal .......................................................... 7
1.4 Adjustment ............................................................................ 8
1.5 Antennas............................................................................. 13
2 Types and versions
2.1 Type survey ........................................................................ 14
2.2 Type code........................................................................... 15
2.3 Bus configuration ............................................................... 16
3 Mounting and installation
3.1 General installation instructions ........................................ 22
3.2 Measurement of liquids ..................................................... 24
3.3 Measurement in standpipe (surge or bypass tube) ...... 25
3.4 False echoes ...................................................................... 32
3.5 Installation mistakes ........................................................... 34
Contents
2 VEGAPULS 56 Profibus PA
Contents
4 Electrical connection
4.1 Connection – Connection cable – Screening ................... 36
4.2 Sensor address ................................................................. 39
4.3 Connection of the sensor .................................................. 40
4.4 Connection of the external indicating
instrument VEGADIS 50 .................................................... 42
5 Setup
5.1 Adjustment media .............................................................. 43
5.2 Adjustment with VVO ......................................................... 44
5.3 Sensor adjustment with the adjustment
module MINICOM ............................................................... 66
6 PA function diagram ............................................................... 72
7 Diagnosis
7.1 Simulation ............................................................................ 76
7.2 Error codes ........................................................................ 76
8 Tec hnical data
8.1 Data ..................................................................................... 77
8.2 Approvals ........................................................................... 84
8.3 Data format of the output signal ........................................ 85
8.4 Dimensions ......................................................................... 86

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 work on the instruments, apart from that in­volved in normal installation and electrical con­nection, must be carried out only by qualified VEGA personnel.
VEGAPULS 56 Profibus PA 3

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 and come with the Ex ap­proved instruments.

1 Product description

Level measurement of high temperature processes or products with high tempera­tures was previously very difficult or even impossible. If such measurement also had to be done under high pressure, there was practically no measuring system available at all, let alone a non-contact measurement system with good measuring accuracy.
Up to now, levels in distillation and stripper columns (e.g. of sump, plate or head prod­ucts) could usually only be measured by pressure transmitters or differential pressure measurements. The installation required for such pressure measuring systems (pressure cables, pressure transmitters…) is consider­able and expensive, often amounting to sev­eral times the value of the sensor itself. Be­cause of the lack of suitable alternatives, instrumentation departments have not only had to accept this fact, but also the high maintenance costs (cleaning of measuring pipes, errors by condensation, buildup on the diaphragm…) and the often inadequate accuracy (temperature errors, density fluc­tuations, installation faults…).
In the petrochemical industry, the require­ments for a non-contact level sensor are therefore the following:
• independent of pressure and temperature
• process temperature up to 400°C
• process pressure up to 64 bar
• high resistance wetted parts for universal use
• accuracy 0.1 %
• rugged metal housing
• Ex approved (available in EEx d and EEx ia)
• loop-powered as well as usable in digital networks
This initial set of requirements defined the development goals for the VEGAPULS 56 series, a high-temperature radar level meas­uring system. The series represents a com­pletely new development of high-temperature radar sensors for temperatures up to 400°C and pressures up to 64 bar.
Product description
These sensors would not have been possible without the recent new results of materials research and production technology. A specially developed ceramic (with high­frequency properties similar to those of the plastics normally used) is used as coupling material. As opposed to plastic, this ceramic has a very high chemical and thermal resist­ance.
The sensor materials in contact with the proc­ess are all highly resistant. This refers not so much to the flange material of high-alloy stainless steel (1.4571 or superior), as to the specially developed ceramic (Al components connecting it. The ceramic rod receives the radar signals from the high­frequency module and acts with its cone­shaped end as emitter and receiver. The seal between stainless steel flange and ceramic rod is made with a Tantalum seal ring.
) and the
2O3

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.
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 impulses reflected by the sensor environment and the product are received by the antenna as radar ech­oes. The running period of the radar im­pulses from emission to reception is proportional to the distance and hence to the level.
4 VEGAPULS 56 Profibus PA
Product description
Meas. distance
emission - reflection - reception
The radar impulses are emitted by the an­tenna system as impulse 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 impulse inter­vals, the antenna system operates as 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.
Through this, it is possible for VEGAPULS series 56 radar sensors to process the slow­motion pictures of the sensor 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).
Virtually 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 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 ensure a sufficient re­flection for a reliable measurement.
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 in a slow­motion picture, then freezes and processes them.
All products with a dielectric constant ε more than 2.0 reflect radar impulses suffi­ciently (note: air has a dielectric constant ε
1).
%
50 40 30 20 10
5 %
5
0
2
4 6 8 12 14 16 18
0
25 %
10
40 %
20
of
r
r
ε
r
Reflected radar power dependent on the dielectric constant of the measured product
t
t
Time transformation
VEGAPULS 56 Profibus PA 5
of
Product description
The signal reflection grows stronger with increasing product conductivity or dielectric constant. Hence virtually all products can be measured.
With standard flanges of DN 50 to DN 250, ANSI 2“ to ANSI 10“ the sensor antenna sys­tems can be adapted to various products and measuring environments. The high­quality materials of the sensors 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 reliable
Unaffected by temperature, pressure and individual gas atmospheres, VEGAPULS radar sensors are ideal for non-contact, fast and accurate level measurement of various 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
10
0
0,8 %
20 30 40 60
50
Pressure influence: Error with pressure increase very low (e.g. at 50 bar 1.44 %)
0,023 %
3 %
70 80 90 110 120 130 140
100
bar

1.2 Application features

Applications
• level measurement of liquids, limited use in solids
• measurement also in vacuum
• all slightly conductive materials and all substances with a dielectric constant
ε
> 2.0 can be measured
r
• measuring ranges 0 … 20 m
Two-wire technology
• power supply and output signal on one two-wire cable
• digital output signal
Rugged and abrasionproof
• non-contact
• high resistance materials
Exact and reliable
• resolution 1 mm
• unaffected by noise, vapours, dusts, gas compositions and inert gas stratification
• unaffected by varying density and tem­perature of the medium
• measurement of pressures up to 64 bar and product temperatures up to 350°C
Communicative
• individual wiring, with 15 sensors on one two-wire cable (digital output signal)
• integrated measured value display
• optional display module up to 25 m sepa­rate from the sensor
• connection to all bus systems: Interbus S, Modbus, Siemens 3964R, Profibus DP, Profibus FMS, ASCII
• adjustment from PLC level
Ex approvals
• CENELEC, FM, ABS, LRS, GL, LR, ATEX, PTB, FCC
VEGAPULS series 56 sensors enable level measurement with radar in systems where it was previously not used due to high costs.
6 VEGAPULS 56 Profibus PA
Product description

1.3 Profibus output signal

PROPRO
PROcess
PROPRO sult of a joint project of thirteen companies and five universities. The companies Bosch, Klöckner-Möller and Siemens played a deci­sive role. The specifications of the bus are described in the protocol layers 1, 2 and 7 of the ISO/OSI reference model and are avail­able from the PNO (Profibus User Organisa­tion). Layers 3 … 5 have not yet been developed as a standard, leaving Profibus with far-reaching perspectives for the future.
Today approx. 600 companies make use of Profibus technology and belong to the PNO, Profibus Specification. Profibus Periphery and Profibus mation.
As a process automation bus, Profibus PA enables power supply over the bus. Up to 32 sensors with power supply and measuring signal can be operated on a shielded two­wire cable that carries both power supply and measuring signal. In Ex areas, up to ten sensors can be connected from the PA level to one two-wire cable (EEx ia).
Bus structure
A Profibus system with DP and PA segments consists of up to 126 Master and Slave par­ticipants. Data are always exchanged from point to point, with the data traffic being ex­clusively controlled and checked by master devices. Communication is carried out ac­cording to the Token-Passing procedure. This means that the master holding the Token can contact the slaves, give instructions, enquire data and cause the slaves to receive and transmit data. After the work is done or after a predetermined time interval, the Token is passed on by the master to the next mas­ter.
FIFI
BUSBUS
FIeld
BUS (PROFIBUS) is the re-
FIFI
BUSBUS
FMSFMS
FMS stands for Fieldbus Messaging
FMSFMS
DPDP
DP for Decentralised
DPDP
PP
AA
P
A for Process Auto-
PP
AA
Master-Class 1
is the actual automation system, i.e. the proc­ess control computer or the PLC that en­quires and processes all measured values.
Master-Class 2
One or several Master-Class 2 can operate in a Profibus network. As a rule, Master-Class 2 devices are engineering, adjustment or visu­alisation stations. The VEGA adjustment soft­ware VVO (VEGA Visual Operating) operates as Master-Class 2 participant on the DP bus and can work on an engineering PC, on an adjustment PC or on the process control computer and can access any VEGA sensor on the PA level.
Instrument master file
A so-called GSD (instrument master file) is provided with the VEGAPULS Profibus sen­sor. This file is necessary to integrate the sensor in the bus system. The GSD contains, beside the sensor name and manufacturer, the sensor-specific communication param­eters which are necessary for a stable inte­gration of the sensor in the bus.
Load the GSD belonging to the sensor into your bus configuration program. If the GSD is not available, it can be downloaded from the VEGA homepage: http://www.vega.com.
Do not mistake the GSD for the EDD (Elec­tronic Device Description), which is neces­sary for the PDM environment and can also be found on the VEGA homepage.
VEGAPULS 56 Profibus PA 7
Product description

1.4 Adjustment

Each measuring situation 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 output of echo curves or the calculation of vessel linearisation curves by means of vessel dimensions are only two examples.
Profibus adjustment structure
In the Profibus environment, there are differ­ent adjustment concepts and adjustment tools which often differ considerably from manufacturer to manufacturer. From the us­er’s point of view, a manufacturer-independ­ent adjustment program which could be operated directly on the Profibus DP, as well as at any system node (e.g. the engineering station or the process control), would be ideal.
In the past, only the program "SIMATIC PDM“, based on the HART ture, could fulfil this wish (though with the limitations common to HART
®
HART
, the availability of an instrument-spe­cific database for a comprehensive adjust­ment with PDM (Process Device Managing) is a requirement. Otherwise, only the basic instrument functions, such as adjustment, are available. In the PDM environment, this instru­ment-specific database is called EDD (Elec­tronic Device Description), in perfect analogy to the HART
®
environment which also re­quires, except for the VEGA HART ments, a DD (Device Description) for each sensor.
®
adjustment struc-
®
). As with
®
instru-
We are aware of the disadvantages of the
®
HART
environment: for each sensor/partici­pant, an individual DD must be loaded, which in addition, must always be the latest and most up-to-date DD. Special adjustment options such as e.g., the output of an echo curve, are available neither with HART
®
nor with PDM. User-friendly adjustment is out of the question. With VEGA’s adjustment pro­gram VVO, those restrictions belong to the past.
The legitimate wish of many Profibus users for a manufacturer-independent adjustment tool without EDD has been realised in the form of PACTware number of process technology companies developed PACTware
TM 1)
. An association of a
TM
: a Process Automa­tion Configuration Tool that can run different manufacturer software tools under a stand­ardized user interface and adjustment struc­ture. Specialists call this technology Field Device Transcription. Just as different Win­dows printer drivers enable operation of completely different printers under a single user interface, PACTware
TM
enables operation of all field instruments under a single user interface. Instrument-specific databases (EDD), like those required for SIMATIC PDM, are not necessary.
As a result of this development, three adjust­ment media are available for VEGA-Profibus sensors:
- adjustment with the PC and the adjustment
program VVO (VEGA Visual Operating) as stand-alone tool, on the segment coupler or directly on the sensor.
- adjustment with the detachable adjustment
module MINICOM in the sensor
- adjustment with the SIMATIC PDM adjust-
ment program (requires EDD instrument databases) from the control room.
- adjustment with the universal adjustment
interface PACTware
TM
on the sensor, from
the control room or on the segment coupler.
8 VEGAPULS 56 Profibus PA
Product description
Adjustment with the adjustment pro­gram VVO - VEGA Visual Operating
The setup and adjustment of the radar sen­sors is generally done on the PC with the adjustment program VEGA Visual Operating (VVO) or with PACTware The programs lead quickly through adjust­ment and parameter setting by means of pictures, graphics and process visualisations.
TM
under Windows®.
Note:
The adjustment program VVO must be avail­able in version 2.70 or higher.
The VEGA adjustment software VVO (VEGA Visual Operating) operates either as a subprogram of the host program PACTware
TM
acc. to the FDT concept (Field Device Tool) or as an independent adjustment program on any PC, engineering station or process con­trol computer.
The adjustment program recognises the sensor type
Visualised input of a vessel linearisation curve in the adjustment program VVO
VEGA’s adjustment program VVO can ac­cess the adjustment options of VEGA sen­sors in their entirety and, if necessary, can update the complete sensor software. To do this, the adjustment program must be in­stalled on a PC which is equipped with a Profibus Master Class 2 interface card or the interface adapter VEGACONNECT 3.
The PC with the Profibus interface card can be connected directly to any point on the DP bus with the standard RS 485 Profibus cable.
In conjunction with the adapter VEGACONNECT, the PC can be connected directly to the sensor. VEGACONNECT com­municates via a small jack directly with the respective sensor.
The adjustment and parameter data can be saved at any time on the PC with the adjust­ment software and can be protected by passwords. If necessary, the adjustments can be transferred quickly to other sensors.
VEGAPULS 56 Profibus PA 9
In practice, the adjustment program VVO is often installed as a tool on an engineering station or operating station. VVO then ac­cesses all VEGA sensors directly over the bus via the Profibus interface card (e.g. from Softing) as Master Class 2, from the DP level to the PA level (via segment coupler) right down to the individual sensor.
Beside the instrument master file (GSD), with which a sensor is logged into the Profibus system, the majority of all Profibus sensors requires for adjustment, beside the specific adjustment software, also a so-called EDD (Electronic Device Description) for each sensor, in order to access and adjust the sensor from the bus levels. This is not the case with VVO. The adjustment software VVO can communicate at any time with all VEGA sensors without the help of a special database. Of course, all other non-Profibus VEGA sensors can be adjusted with the adjustment software as well (4 … 20 mA sensors or VBUS sensors). With VEGA sen­sors, it is not necessary to go looking for the latest EDD. This is the basic prerequisite for a manufacturer-independent adjustment program, like PACTware
TM
, anticipated by
many users, see following pages.
Product description
10 VEGAPULS 56 Profibus PA
Product description
Adr. 21
SPS
Adr. 22
VVO
3
PA-
Adr. 23
Bus
Master-Class 1
Adr. 1
DP-Bus
Adr. 24
Profibus DP interface card as Master-Class 2 (e.g. Softing)
Adr. 10
Adr. 57
Segment coupler
Adr. 25 … 56
2
3
Adr. 58
Adr. 59
(max. 32 participants)
Adr. 60
Adr. 26
Adr. 25
Adr. 27
Adr. 28
Adr. 29
Adjustment of the VEGAPULS radar sensors from process control via a Profibus interface card in the process control computer or in an additional PC. The adjustment software VEGA Visual Operating (VVO) accesses via the interface (interface card) the sensors bidirectionally.
VEGAPULS 56 Profibus PA 11
Product description
Adjustment with adjustment module MINICOM
With the small (3.2 cm x 6.7 cm) 6-key ad­justment module with display, you carry out the adjustment 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
The adjustment module can be removed easily so that unauthorised people cannot modify the sensor setting.
ESC
+
-
Tank 1 m (d)
12.345
OK
2
PA-Bus
ESC
+
-
Tank 1 m (d)
12.345
OK
4
Adjustment with the SIMATIC PDM adjustment program
For adjustment of all essential functions of the VEGA sensor with the adjustment station SIMATIC PDM from Siemens, a so-called EDD is required. Without this EDD, only the basic functions such as min./max. wet adjust­ment or integration time can be adjusted with the PDM adjustment program. Further impor­tant adjustment functions, such as the input of the "
Meas. environment
storage are not available without EDD. After
ESC
integration of the EDD files in the Simatic PDM
OK
adjustment software, all important adjustment
“ or a false echo
functions are accessible. If it is not at hand, the obligatory GSD (instrument master file) as well as the EDD (Electronic Device De­scription) necessary for PDM can be downloaded from the VEGA-Homepage (http://www.vega.com).
Adjustment with PACTware
The above-mentioned program PACTware is a manufacturer-independent automation/ configuration tool, by which access to instru­ments of different manufacturers (Krohne, Pepperl + Fuchs, VEGA, VIKA- Bürkert…) is possible. The VEGA adjustment software VVO works as a subprogram/menu. PACTware options for the sensor/instrument being accessed.
PACTware constructed in tree structure. Operating instructions for PACTware the PACTwareTM documentation. They are not described in this operating instructions manual.
TM
activates the required menu
TM
looks different than VVO and is
TM
can be found in
TM
TM
max. 25 m
Adjustment with detachable adjustment module. The adjustment module can be plugged into the radar sensor or into the external indicating instrument VEGADIS 50.
12 VEGAPULS 56 Profibus PA
Product description

1.5 Antennas

The antenna is the eye of the radar sensor. An uninitiated observer would probably not realise how carefully the antenna geometry must be adapted to the physical properties of electromagnetic fields. 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 various antenna systems are available.
Horn antenna
Horn antennas focus the radar signals very well. Made of 1.4571 (stainless steel) or Hastelloy C22 they are very rugged, and physically as well as chemically resistant. Horn antennas are used for measurement in closed or open vessels.
Pipe antenna
Only in conjunction with a meas­uring tube, i.e. with a surge or bypass tube (which can also be angled), do horn antennas form a complete antenna system. Pipe antennas are mainly suit­able for very agitated products or for products with very small dielectric constant.
The antenna can be with or with­out horn. The antennas are char­acterised by a very high antenna gain. High reliability can be achieved even with products having poor reflective proper­ties.
For the radar signals, the meas­uring tube acts as a conductor.
DN 50
The running time of the radar signal 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 precise level signals ensured.
DN 150
DN 80
DN 250
VEGAPULS 56 Profibus PA 13

2 Types and versions

VEGAPULS 56 sensors are a newly devel­oped generation of very compact, high tem­perature radar sensors. They enable for the first time non-contact level measurements under high temperatures and pressures. They offer the advantages of radar level measurement for applications in which the special advantages of radar could not be previously applied due to extreme process conditions.
VEGAPULS 56 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. This operating instructions manual describes the sensors with digital output signal.
Types and versions

2.1 Type surve y

General features
• Level measurement of processes and products under high temperatures and high pressures
• Measuring range 0 … 20 m
• Ex approved in Zone 1 and Zone 10 (IEC) or Zone 0 and Zone 20 (ATEX) classifica­tion mark EEx ia IIC T6 or EEx d ia IIC T6
• Integrated measured value display
• External measured value display which can be mounted at a distance of up to 25 m in Ex area
Survey of features
Signal output
- digital transmission of measuring signals to a VEGAMET signal conditioning instrument or the VEGALOG processing system
VEGAPULS 56 DN 150
VEGAPULS 56 DN 50 pipe antenna
VEGAPULS 56 DN 80 pipe antenna
Power supply – two-wire technology (voltage supply and
digital signal via one two-wire cable)
Process fitting – DN 50; ANSI 2“ – DN 80; ANSI 3“ – DN 100; ANSI 4“ – DN 150; ANSI 6“ – DN 200; ANSI 8“ – DN 250; ANSI 10“
Adjustment –PC – adjustment module in the sensor – adjustment module in external indicating
instrument
Antennas – horn antenna with stainless steel horn and
ceramic tip
– standpipe antenna only with ceramic tip or
with small horn and ceramic tip
14 VEGAPULS 56 Profibus PA
Types and versions

2.2 Type code

56… High temperature radar sensor …K 4 … 20 mA output signal (not described in this operating instruction manual) …P Output signal Profibus PA
VEGAPULS 56 V EXXX X X X X X X X
J - Tube extension for horn antenna X - without
A - Aluminium housing D - Aluminium housing with Exd connection housing
T - Seal of the antenna system of Tantalum
KVX - Process fitting DN 50 PN 16 (for standpipe) LV6 - Process fitting DN 80 PN 16 (for standpipe) EV1 - Process fitting DN 100 PN 16 (for standpipe) FV2 - Process fitting DN 150 PN 16 SVX - Pr ocess fitting ANSI 2“ 150 psi (for standpipe) WV6 - Process fitting ANSI 3“ 150 psi (for standpipe) PV1 - Process fitting ANSI 4“ 150 psi (for standpipe) VV2 - Process fitting ANSI 6“ 150 psi 0V2 - Process fitting ANSI 6“ 300 psi 1V2 - Process fitting ANSI 6“ 600 psi (1.4571) 1M2 - Process fitting ANSI 6“ 600 psi (Hastelloy C22) YYY - Ot her pr ocess connections and materials
X - without display A - with integrated display
X - without adjustment module MINICOM
B - with adjustment module MINICOM (mounted)
B - 20 … 72 V DC; 20 … 250 V AC; 4 … 20 mA; HART D - Two-wire (loop-powered); 4 … 20 mA; HART E - Power supply via signal conditioning instrument G - Profibus PA (power supply from segment coupler) P - 90 … 250 V AC (only in USA) N - 20 … 36 V DC, 24 V AC (only in USA) Z - Power supply via signal conditioning instrument (only in USA)
®
®
.X - FTZ approval (Germany) EX.X - Approved Zone 1 and Zone 10 EX0.X - Ex approved Zone 0
K - Analogue 4 … 20 mA output signal
(two-wire technology)
P - Digital output signal (two-wire technology) Profibus
Instrument series for high temperature application
Measuring technology (PULS for radar)
VEGAPULS 56 Profibus PA 15
Types and versions

2.3 Bus configuration

The type of radar sensor you use depends on your process requirements and mounting conditions, as well as on the requirements of your control, regulative, or process control system.
VEGAPULS 56 Profibus radar sensors are sensors for use in Profibus PA environment. Profile 3 has been implemented in the sen­sors. A measuring system consists of one or several sensors, one or several segment couplers and one DP master computer, such as e.g. a S7 PLC with Profibus interface or a process control system with Profibus DP­Master-Slot. The processing unit, e.g. the PLC, evaluates the level-proportional, digital measuring signals in a number of evaluation routines and puts them to use process-spe­cifically.
On the following four pages you will see schematic illustrations of the bus configura­tion.
The automation system as Master-Class 1 takes over bus control completely. It reads out all signals cyclically and, if necessary, gives instructions to the participants (e.g. sensors). Besides this, additional master systems (e.g. visualisation systems or ad­justment tools) can be connected to the DP bus. These systems operate as so-called Master-Class 2 participants. Like the Master­Class 1 system, they can read out signals, give instructions and operate in the acyclical mode.
A DP bus does not allow power supply via signal cable, whereas the PA bus does. Both, DP and PA, require at a minimum a screened two-wire cable. The DP bus can additionally have up to 8 cores (screened), of which some can be supply cables (see also "Instal­lation Guides PA + DP“ of the Profibus User Organisation (PNO).
Each participant on the bus must have an unambiguous address. The addressing covers both bus levels. A Profibus DP net­work can have max. 126 participants, includ­ing all participants on the PA level. In practice, each Master-Class 1 computer gets address 1 and the Master-Class 2 comput­ers address 10 … 20. As a rule, the slaves or participants get the addresses 21 … 126. On the Profibus PA network segment, max. 32 sensors are possible on one PA segment coupler.
Ex environment
In Ex environment, intrinsically safe (EEx ia) PA sensors are used with Ex segment cou­plers. Generally, the number of PA sensors on a segment coupler (Ex or non Ex) de­pends on the current requirement of the sensors and on the current supplied by the segment coupler. Segment couplers for EEx ia environment provide 90 … 110 mA. The number of sensors results from the sum of:
- the basic current intake of all sensors
- plus 9 mA communication signal
- plus the leakage currents of all sensors
- plus a recommended current reserve (approx. 10 mA)
The min. basic current has been set at 10 mA according to the Profibus specification. VEGA Profibus sensors constantly consume a basic current of 10 mA and operate without leakage current requirement, so that in Ex environment, up to max. ten VEGA sensors can be operated on one segment coupler.
16 VEGAPULS 56 Profibus PA
Types and versions
VEGAPULS 56 Profibus PA 17
Types and versions
1
Master-Class 1
Bus terminator
3...9
Profibus PA (31,25 kBit/s)
Profibus DP
21
Profibus interface card
RS 232
22...54
3
RS 485
10
Master-Class 2
Segment coupler
Bus terminator
2
22
23
24
53
54
VEGACONNECT 3
PA segment on segment coupler: 1 … 32 sensors on one two-wire cable (Ex: 10 sensors)
18 VEGAPULS 56 Profibus PA
Types and versions
Profibus DP segment level 1 … 126 participants including all DP and PA participants. Through segment couplers and PA segments, the trans­mission rate, also on the DP level, is determined by the slowest coupler or participant on the Profibus DP and PA network.
Bus terminator
3...9
M
Segment coupler
3...9
3~M
89
90
55
56...88
Bus terminator
2
Profibus PA
2
Bus terminator
56
57
87
88
PA segment on segment coupler: 1 … 32 sensors on one two-wire cable (Ex: 10 sensors)
VEGAPULS 56 Profibus PA 19
Types and versions
1
Master-Class 1
Bus terminator
VEGALOG
Profibus PA (31,25 kBit)
3~M
3…9
Profibus DP
Profibus interface card
21
3
RS 485
22
10
Master-Class 2
VEGACONNECT 3
4
RS 232
1
2
3
5
11
12
4
1 … 15 PA sensors per two-wire cable
13
15
14
with independent address zone (Ex: 10 sensors)
20 VEGAPULS 56 Profibus PA
Types and versions
Profibus DP segment level 1 … 126 participants including all DP and PA participants. Up to 12 MBit/s transmission rate on DP level. In the PA segments 31.25 kBit/s transmission rate.
VEGACONNECT 3
4 … 20 mA (HART )
2
4
4
4
2
2
2
Profibus PA (31,25 kBit)
3…9
23
M
3…9
24
25
VEGALOG
VBUS
Outputs
2
2
2
2
®
2
2
2
2
2
0/4…20 mA
0…10 V
VBUS
2
Bus termi­nator
Profibus PA: 1 … 15 PA sensors per two-wire cable with independent address zone (Ex: 10 sensors)
VBUS: 1 … 15 sensors per two­wire cable Exd: also 15 Ex ia: 5 sensors
VEGAPULS 56 Profibus PA 21
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3 Mounting and installation

3.1 General installation instructions

Measuring range
The reference plane for the measuring range of the sensors is the lower edge of the flange. The measuring range is 0 … 20 m. For meas­urement in surge or bypass tubes (pipe antenna) the max. measuring distance is reduced (see "Technical data - Measuring range“).
Mounting and installation
Keep in mind that in measuring environments where the medium can reach the sensor flange, buildup can form on the antenna which can cause measurement errors. The min. distance of the antenna to the medium should be 5 cm.
Reference plane
min. meas. distance
full
min.
Meas. range
empty
max. meas. distance 20 m
Measuring range (operating range) and max. measuring distance Note: Use of the sensors for applications with solids is limited.
False reflections
Flat obstructions and struts cause large false reflections. They reflect the radar signal with high energy density.
Interfering surfaces with a round profile dif­fuse the reflected radar signals and cause
If flat obstructions in the range of the radar signals cannot be avoided, we recommend the installation of a deflector plate to scatter the reflected signals. Due to this scattering, the interfering signals will be low in amplitude and so diffuse that they can be filtered out by the sensor.
false reflections with lower energy density. Hence, they are less critical than reflections from a flat surface.
Round profiles diffuse radar signals
min. meas. distance
min. meas. distance
full
empty
Profile with smooth interfering surfaces cause large false signals
22 VEGAPULS 56 Profibus PA
A deflector causes signal scattering
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 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 100 % area of the emission cone.
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.
Meas. distance
0 m
30˚
10 m
40˚
20 m
6,8 m 6,8 m
0
Emission cone of a DN 100 horn antenna
Meas. distance
0 m
100 %
emitted power
50 %
5,3 m5,3 m
Optimum measuring conditions exist when the emission cone reaches the measured product perpendicularly and when the emis­sion cone is free from obstructions.
10 m
20 m
5,0 m
3,5 m
Emission cone of a DN 150 horn antenna
VEGAPULS 56 Profibus PA 23
20˚
30˚
0
100 %
emitted power
50 %
emitted power
5,0 m
3,5 m
Mounting and installation
Meas. distance
0 m
14˚
100 %
22˚
0
emitted power
50 %
3,8 m
2,4 m
emitted power
10 m
20 m
3,8 m
2,4 m
Emission cone of a DN 250 horn antenna
Heat insulation
In process temperatures of more than 200°C the rear of the flange must be insulated to protect the sensor electronics from radiated heat.
We recommend integrating the sensor insula­tion into the vessel insulation and extending it approx. up to the first tube segment.

3.2 Measurement of liquids

Sensor on DIN socket piece
Most commonly, the mounting of radar sen­sors is done 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.
Reference plane
Mounting on DIN socket piece
With a longer DIN socket piece, the horn antenna must protrude at least 10 mm out of the socket.
40°C
60°C
> 10 mm
350°C
100°C
240°C
Mounting on longer DIN socket piece
Vessel insulation
max. 350°C
When mounting on dished vessel tops, the antenna must also protrude at least 10 mm beyond the longer side of the socket).
Heat insulation
24 VEGAPULS 56 Profibus PA
Mounting and installation
> 10 mm
Sensor 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 economical solution. The top side of the vessel is the reference plane.
Mounting on a dished vessel top
On dished tank ends, please do not mount the instrument in the centre or close to the vessel wall, but approx.
1
/2 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.
Reference plane
1
/2 vessel radius
Mounting on dished tank ends
Reference plane
Mounting directly on the flat vessel top

3.3 Measurement in standpipe (surge or bypass tube)

General instructions
Pipe antennas are preferred in vessels which contain many installations, e.g. heating tubes, heat exchangers or fast-running stirrers. Measurement is then possible where the product surface is very turbulent, and vessel installations cannot cause false echoes.
Through focusing of the radar signal within the measuring tube, even products with small dielectric constants (ε reliably measured in surge or bypass tubes. Please note the following instructions.
Surge pipes which are open at the bottom must extend over the full measuring range (i.e. down to 0% level), as a measurement is only possible within the tube.
It is advantageous to install a deflector below the end of the tube. The product can then be reliably detected around the min. level. This is particularly important for products with a dielectric constant of less than 5.
= 1.6 up to 3) can be
r
VEGAPULS 56 Profibus PA 25
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Mounting and installation
Surge pipe welded to the tank
Surge pipe in the socket piece
Marking holes in the intermedi­ate flange
max.
Vent hole
Deflector
min.
Pipe antenna systems in the tank
Make sure that the required upper vent hole is on one axis with the marking hole in the intermediate flange (polarisation direction of the radar signals).
Marking hole
100 %
;
;
;
;
;
0 %
Tube flange system as bypass tube
As an alternative to a surge pipe in the ves­sel, a pipe antenna can be mounted outside the vessel as a bypass tube.
When measuring 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 DN 100 only 19 m instead of 20 m).
Align the sensor such that the marking hole in the intermediate flange is on one axis with the tube holes or tube openings. The polarisation of the radar signal enables a considerably stabler measurement with this alignment.
Extended bypass tube on a vessel with turbulent product movements
26 VEGAPULS 56 Profibus PA
100 %
75 %
0 %
Mounting and installation
Adhesive products
For adhesive products, a surge pipe with a larger inner diameter should be used. For nonadhesive 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 nomi­nal diameter of 100 mm to 150 mm to prevent buildup from causing measurement errors.
DN 50
ø 50
DN 80
ø 80
Standpipe measurement of inhomoge­neous products
If you want to measure inhomogeneous prod­ucts 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.
ø 100
DN 100
DN 150
ø 150
homogeneous liquids
inhomogeneous liquids
Openings in a surge pipe for mixing of inhomogene-
slightly inhomogeneous liquids
strongly inhomogeneous liquids
ous products
The more inhomogeneous the measured product, the closer together the openings
Pipe antenna with DN 50, DN 80, DN 100 and DN 150
VEGAPULS 56 Profibus PA 27
should be.
Mounting and installation
Polarisation direction
Due to radar polarisation, the holes or slots must be positioned in two rows offset by 180°. The radar sensor must be mounted so that the marking hole of the sensor (located in the intermediate flange) is on one axis with the row of holes in the standpipe.
Marking hole
Rows of holes in one axis with the marking hole
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).
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.
Make sure there is a ventilation hole in the standpipe.
DN 50
Ball valve
Standpipe ventilation
Correct
Marking hole
The sensor must be directed with the marking hole to the rows of holes or openings.
28 VEGAPULS 56 Profibus PA
Wrong
ø50
Deflector
Tube antenna system with ball valve cutoff in measur­ing tube
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