Vega VEGAFLEX 81 User manual

Operating Instructions
TDR sensor for continuous level and
interface measurement of liquids
VEGAFLEX 81
Modbus and Levelmaster protocol
Document ID: 41828

2
Contents
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
Contents
1 About this document
1.1 Function ............................................................................. 4
1.2 Target group ....................................................................... 4
1.3 Symbolism used................................................................. 4
2 For your safety
2.1 Authorised personnel ......................................................... 5
2.2 Appropriate use.................................................................. 5
2.3 Warning about incorrect use............................................... 5
2.4 General safety instructions................................................. 5
2.5 CE conformity..................................................................... 5
2.6 NAMUR recommendations ................................................ 6
2.7 Environmental instructions ................................................. 6
3 Product description
3.1 Conguration...................................................................... 7
3.2 Principle of operation.......................................................... 8
3.3 Packaging, transport and storage..................................... 10
3.4 Accessories and replacement parts ................................. 10
4 Mounting
4.1 General instructions ......................................................... 13
4.2 Instructions for installation................................................ 13
5 Connecting to power supply and bus system
5.1 Preparing the connection ................................................. 19
5.2 Connecting....................................................................... 19
5.3 Wiring plan ....................................................................... 21
5.4 Switch-on phase............................................................... 22
6 Set up with the indicating and adjustment module
6.1 Adjustment volume........................................................... 23
6.2 Insert indicating and adjustment module .......................... 23
6.3 Adjustment system........................................................... 24
6.4 Parameter adjustment ...................................................... 24
6.5 Saving the parameter adjustment data............................. 41
7 Setting up sensor and Modbus interface with PACTware
7.1 Connect the PC ................................................................ 42
7.2 Parameter adjustment with PACTware.............................. 43
7.3 Set up with the quick setup............................................... 44
7.4 Saving the parameter adjustment data............................. 49
8 Set up with other systems
8.1 DD adjustment programs ................................................. 50
8.2 Communicator 375, 475................................................... 50
9 Diagnostics and service
9.1 Maintenance .................................................................... 51
9.2 Diagnosis memory ........................................................... 51
9.3 Status messages.............................................................. 52
9.4 Rectify faults..................................................................... 56
9.5 Exchanging the electronics module.................................. 59

3
Contents
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
9.6 Software update ............................................................... 59
9.7 How to proceed in case of repair...................................... 60
10 Dismounting
10.1 Dismounting steps............................................................ 61
10.2 Disposal ........................................................................... 61
11 Supplement
11.1 Technical data .................................................................. 62
11.2 Basics Modbus................................................................. 70
11.3 Modbus register ............................................................... 72
11.4 Modbus RTU commands ................................................. 74
11.5 Levelmaster commands ................................................... 77
11.6 Conguration of typical Modbus hosts.............................. 81
11.7 Dimensions ...................................................................... 85
Safety instructions for Ex areas
Please note the Ex-specic safety information for installation and op-
eration in Ex areas. These safety instructions are part of the operating
instructions manual and come with the Ex-approved instruments.
Editing status: 2012-11-06

4
1 About this document
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
1 About this document
1.1 Function
This operating instructions manual provides all the information you
need for mounting, connection and setup as well as important instruc-
tions for maintenance and fault rectication. Please read this informa-
tion before putting the instrument into operation and keep this manual
accessible in the immediate vicinity of the device.
1.2 Target group
This operating instructions manual is directed to trained qualied
personnel. The contents of this manual should be made available to
these personnel and put into practice by them.
1.3 Symbolism used
Information, tip, note
This symbol indicates helpful additional information.
Caution: If this warning is ignored, faults or malfunctions can result.
Warning: If this warning is ignored, injury to persons and/or serious
damage to the instrument can result.
Danger: If this warning is ignored, serious injury to persons and/or
destruction of the instrument can result.
Ex applications
This symbol indicates special instructions for Ex applications.
• List
The dot set in front indicates a list with no implied sequence.
→ Action
This arrow indicates a single action.
1 Sequence
Numbers set in front indicate successive steps in a procedure.
Battery disposal
This symbol indicates special information about the disposal of bat-
teries and accumulators.

5
2 For your safety
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
2 For your safety
2.1 Authorised personnel
All operations described in this operating instructions manual must
be carried out only by trained specialist personnel authorised by the
plant operator.
During work on and with the device the required personal protective
equipment must always be worn.
2.2 Appropriate use
VEGAFLEX 81 is a sensor for continuous level measurement.
You can nd detailed information on the application range in chapter
"Product description".
Operational reliability is ensured only if the instrument is properly
used according to the specications in the operating instructions
manual as well as possible supplementary instructions.
2.3 Warning about incorrect use
Inappropriate or incorrect use of the instrument can give rise to
application-specic hazards, e.g. vessel overll or damage to system
components through incorrect mounting or adjustment.
2.4 General safety instructions
This is a state-of-the-art instrument complying with all prevailing
regulations and guidelines. The instrument must only be operated in a
technically awless and reliable condition. The operator is responsible
for the trouble-free operation of the instrument.
During the entire duration of use, the user is obliged to determine the
compliance of the necessary occupational safety measures with the
current valid rules and regulations and also take note of new regula-
tions.
The safety instructions in this operating instructions manual, the na-
tional installation standards as well as the valid safety regulations and
accident prevention rules must be observed by the user.
For safety and warranty reasons, any invasive work on the device
beyond that described in the operating instructions manual may be
carried out only by personnel authorised by the manufacturer. Arbi-
trary conversions or modications are explicitly forbidden.
The safety approval markings and safety tips on the device must also
be observed.
2.5 CE conformity
The device fullls the legal requirements of the applicable EC guide-
lines. By axing the CE marking, we conrm successful testing of the
product.
You can nd the conformity certicate in the download section of our
homepage.

6
2 For your safety
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
The instrument is designed for use in an industrial environment.
Nevertheless, electromagnetic interference from electrical conductors
and radiated emissions must be taken into account, as is usual with a
class A instrument according to EN 61326-1. If the instrument is used
in a dierent environment, its electromagnetic compatibility with other
devices must be ensured by suitable measures.
2.6 NAMUR recommendations
NAMUR is the automation technology user association in the process
industry in Germany. The published NAMUR recommendations are
accepted as the standard in eld instrumentation.
The device fullls the requirements of the following NAMUR recom-
mendations:
• NE 21 – Electromagnetic compatibility of equipment
• NE 43 – Signal level for malfunction information from measuring
transducers
• NE 53 – Compatibility of eld devices and indicating/adjustment
components
• NE 107 - Self-monitoring and diagnosis of eld devices
For further information see www.namur.de.
2.7 Environmental instructions
Protection of the environment is one of our most important duties.
That is why we have introduced an environment management system
with the goal of continuously improving company environmental pro-
tection. The environment management system is certied according
to DIN EN ISO 14001.
Please help us full this obligation by observing the environmental
instructions in this manual:
• Chapter "Packaging, transport and storage"
• Chapter "Disposal"

7
3 Product description
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
3 Product description
3.1 Conguration
The type label contains the most important data for identication and
use of the instrument:
2
1
13
14
15
16
12
11
5
3
6
4
7
8
9
10
Fig. 1: Layout of the type label (example)
1 Instrument type
2 Product code
3 Approvals
4 Power supply and signal output, electronics
5 Protection rating
6 Probe length
7 Process and ambient temperature, process pressure
8 Material, wetted parts
9 Hardware and software version
10 Order number
11 Serial number of the instrument
12 Symbol of the device protection class
13 ID numbers, instrument documentation
14 Note to observe the instrument documentation
15 NotiedauthorityforCEmarking
16 Approval directive
With the serial number of the instrument on the type label you have
access to the following data on our homepage:
• Article number of the instrument (HTML)
• Delivery date (HTML)
• Order-specic instrument features (HTML)
• Operating instructions at the time of shipment (PDF)
• Order-specic sensor data for an electronics exchange (XML)
• Test certicate "Measuring Accuracy" (PDF)
For this purpose, move to www.vega.com and "VEGATools".
The instrument contains two dierent electronics in its housing cham-
bers:
• The Modbus electronics for power supply and communication with
the Modbus-RTU
• The sensor electronics for the actual measuring tasks
Type label
Serial number
Electronics design

8
3 Product description
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
2
1
Fig. 2: Position of Modbus and sensor electronics
1 Modbus electronics
2 Sensor electronics
This operating instructions manual applies to the following instrument
versions:
• Hardware from 1.0.0
• Software from 1.0.0
The instrument can be supplied in two dierent electronics versions.
Each electronics version can be identied via the product code on the
type label as well as on the electronics.
• Standard electronics with supply voltage 90 … 253 V AC;
50/60 Hz: Type FX80B.-
• Standard electronics with supply voltage 9.6 … 48 V DC;
20 … 42 V AC: Type FX80I.-
The scope of delivery encompasses:
• Sensor
• Documentation
– this operating instructions manual
– Test certicate measuring accuracy (optional)
– Operating instructions manual "Indicating and adjustment
module" (optional)
– Supplementary instructions "GSM/GPRSradiomodule"
(optional)
– Supplementary instructions manual "Heating for indicating and
adjustment module" (optional)
– Supplementary instructions manual "Plug connector for con-
tinuously measuring sensors" (optional)
– Ex-specic "Safety instructions" (with Ex versions)
– CE declarations of conformity
– if necessary, further certicates
3.2 Principle of operation
The VEGAFLEX 81 is a level sensor with cable or rod probe for
continuous level or interface measurement, suitable for applications
in liquids.
High frequency microwave pulses are guided along a steel rope or
a rod. Upon reaching the product surface, the microwave pulses are
Scope of this operating
instructions manual
Versions
Scope of delivery
Application area
Functional principle -
level measurement

9
3 Product description
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
reected. The running time is evaluated by the instrument and output-
ted as level.
High frequency microwave impulses are guided along a steel cable
or rod. When reaching the product surface, a part of the microwave
impulses is reected. The other part passes the upper product and is
reected a second time by the interface. The running times to the two
product layers are processed by the instrument.
TS
d1
h1
h2
d2
1
L2
L1
Fig. 3: Interface measurement
1 Sensorreferenceplane(sealsurfaceoftheprocesstting)
d1 Distancetotheinterface(HARTvalue1)
d2 Distancetothelevel(HARTvalue3)
TS Thicknessoftheuppermedium(d1-d2)
h1 Height - Interface
h2 Height - Level
L1 Lower medium
L2 Upper medium
Upper medium (L2)
• The upper medium must not be conductive
• The dielectric constant of the upper medium must be known (input
required). Min. dielectric constant: rod version 1.6. You can nd a
list with the dielectric constants on our home page: www.vega.com
• The composition of the upper medium must be stable, no varying
products or mixtures
• The upper medium must be homogeneous, no stratications
within the medium
• Min. thickness of the upper medium 50 mm (1.97 in)
• Clear separation from the lower medium, no emulsion phase, no
mull layer
• If possible, no foam on the surface
Lower medium (L1)
• The dielectric gure must be 10 higher than the dielectric constant
of the upper medium, preferably electrically conductive. Example:
upper medium dielectric constant 2, lower medium at least dielec-
tric constant 12.
Functional principle - in-
terface measurement
Prerequisites for inter-
face measurement

10
3 Product description
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
The instrument is always preset to the application "Level measure-
ment".
For the interface measurement, you can select the requested output
signal with the setup.
3.3 Packaging, transport and storage
Your instrument was protected by packaging during transport. Its
capacity to handle normal loads during transport is assured by a test
according to DIN EN 24180.
The packaging of standard instruments consists of environment-
friendly, recyclable cardboard. For special versions, PE foam or PE
foil is also used. Dispose of the packaging material via specialised
recycling companies.
Transport must be carried out under consideration of the notes on the
transport packaging. Nonobservance of these instructions can cause
damage to the device.
The delivery must be checked for completeness and possible transit
damage immediately at receipt. Ascertained transit damage or con-
cealed defects must be appropriately dealt with.
Up to the time of installation, the packages must be left closed and
stored according to the orientation and storage markings on the
outside.
Unless otherwise indicated, the packages must be stored only under
the following conditions:
• Not in the open
• Dry and dust free
• Not exposed to corrosive media
• Protected against solar radiation
• Avoiding mechanical shock and vibration
• Storage and transport temperature see chapter "Supplement -
Technicaldata-Ambientconditions"
• Relative humidity 20 … 85 %
3.4 Accessories and replacement parts
The indicating and adjustment module PLICSCOM is used for meas-
ured value indication, adjustment and diagnosis. It can be inserted
into the sensor and removed at any time.
You can nd further information in the operating instructions "Indicat-
ingandadjustmentmodulePLICSCOM" (Document-ID 27835).
The interface adapter VEGACONNECT enables the connection of
communication-capable instruments to the USB interface of a PC. For
parameter adjustment of these instruments, an adjustment software
such as PACTware with VEGA-DTM is required.
You can nd further information in the operating instructions "Interface
adapterVEGACONNECT" (Document-ID 32628).
Output signal
Packaging
Transport
Transport inspection
Storage
Storage and transport
temperature
Indicating and adjust-
ment module
Interface adapter

11
3 Product description
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
VEGADIS 61 is an external indicating and adjustment unit for sensors
with single chamber housing and Ex-d double chamber housing.
It is suitable for measured value indication and adjustment of plics®
sensors and is connected to the sensor with a four-wire standard
cable up to 50 m long.
You can nd further information in the operating instructions "VE-
GADIS61" (Document-ID 27720).
VEGADIS 62 is suitable for measured value indication and adjustment
of sensors with HART protocol. It is looped into the 4 … 20 mA/HART
signal cable.
You can nd further information in the operating instructions "VE-
GADIS62" (Document-ID 36469).
The PLICSMOBILE T61 is an external GSM/GPRS radio unit for
transmission of measured values and for remote parameter adjust-
ment of plics® sensors. The adjustment is carried out via PACTware/
DTM by using the integrated USB connection.
You can nd further information in the supplementary instructions
"PLICSMOBILET61" (Document-ID 36849).
The protective cover protects the sensor housing against soiling and
intense heat from solar radiation.
You will nd additional information in the supplementary instructions
manual "Protective cover" (Document-ID 34296).
Screwed anges are available in dierent versions according to the
following standards: DIN 2501, EN 1092-1, ANSI B 16.5, JIS B 2210-
1984, GOST 12821-80.
You can nd additional information in the supplementary instructions
manual "FlangesaccordingtoDIN-EN-ASME-JIS" (Document-ID
31088).
The electronics module VEGAFLEX series 80 is a replacement part
for TDR sensors of VEGAFLEX series 80. There is a dierent version
available for each type of signal output.
You can nd further information in the operating instructions manual
"ElectronicsmoduleVEGAFLEXseries80".
The electronics module Modbus is a replacement part for TDR sen-
sors of VEGAFLEX series 80.
You can nd further information in the operating instructions manual
"ElectronicsmoduleModbusVEGAFLEXseries80".
The indicating and adjustment module can be optionally replaced by
an indicating and adjustment module with heating function.
You can hence use the indicating and adjustment module in a tem-
perature range of -40 … 70 °C.
You can nd further information in the operating instructions "Indicat-
ing and adjustment module with heating" (Document-ID 31708).
External indicating and
adjustment unit
External indicating and
adjustment unit with
HART protocol
External radio unit
Protective cover
Flanges
Electronics module
Electronics module,
Modbus
Indicating and adjust-
ment module with heating

12
3 Product description
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
If you are using an instrument with rod version, you can extend the
rod probe individually with rod extensions of dierent lengths.
The following lengths are available:
• 100 mm
• 200 mm
• 500 mm
• 1000 mm
You can nd further information in the operating instructions manual
"RodextensionVEGAFLEXseries80".
The combination of a bypass tube and a VEGAFLEX 81 enables con-
tinuous level measurement outside the vessel. The bypass consists
of a standpipe which is mounted as a communicating container on
the side of the vessel via two process ttings. This kind of mounting
ensures that the level in the standpipe and the level in the vessel are
the same.
The length and the process ttings can be congured individually. No
dierent connection versions available.
You can nd further information in the operating instructions manual
"BypasstubeVEGAPASS81".
If you mount the VEGAFLEX 81 in a bypass tube or standpipe, you
have to avoid contact to the bypass tube by using a spacer at the
probe end.
You can nd further information in the operating instructions manual
"BypasstubeVEGAPASS81".
Rod extension
Bypass tube
Spacer

13
4 Mounting
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
4 Mounting
4.1 General instructions
With instruments with threaded process tting, suitable tools must be
applied for tightening the hexagon.
Warning:
The housing must not be used to screw the instrument in! Applying
tightening force can damage internal parts of the housing.
Use the recommended cables (see chapter "Connectingtopower
supply") and tighten the cable gland.
You can give your instrument additional protection against moisture
penetration by leading the connection cable downward in front of the
cable entry. Rain and condensation water can thus drain o. This ap-
plies mainly to outdoor mounting as well as installation in areas where
high humidity is expected (e.g. through cleaning processes) or on
cooled or heated vessels.
In the case of instrument housings with self-sealing NPT threads, it is
not possible to have the cable entries screwed in at the factory. The
openings for the cable glands are therefore covered with red protec-
tive caps as transport protection.
Prior to setup you have to replace these protective caps with ap-
proved cable glands or close the openings with suitable blind plugs.
The suitable cable glands and blind plugs come with the instrument.
Make sure that all parts of the instrument exposed to the process, in
particular the active measuring component, process seal and process
tting, are suitable for the existing process conditions. These include
above all the process pressure, process temperature as well as the
chemical properties of the medium.
You can nd the specications in chapter "Technicaldata" and on the
type label.
4.2 Instructions for installation
Mount VEGAFLEX 81 in such a way that the distance to vessel instal-
lations or to the vessel wall is at least 300 mm (12 in). In non-metallic
vessels, the distance to the vessel wall should be at least 500 mm
(19.7 in).
During operation, the probe must not touch any installations or the
vessel wall. If necessary, fasten the probe end.
In vessels with conical bottom it can be advantageous to mount the
sensor in the center of the vessel, as measurement is then nearly
possible down to the lowest point of the bottom. Keep in mind that
measurement down to the tip of the probe is probably not possible.
The exact value of the min. distance (lower blocking distance) is
stated in chapter "Technicaldata".
Screwing in
Moisture
Protective caps
Suitability for the process
conditions
Installation position

14
4 Mounting
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
Fig. 4: Vessel with conical bottom
Plastic vessel/Glass vessel
The guided microwave principle requires a metal surface on the pro-
cess tting. Therefore use in plastic vessels etc. an instrument version
with ange (from DN 50) or place a metal sheet (ø > 200 mm/8 in)
beneath the process tting when screwing it in.
Make sure that the plate has direct contact with the process tting.
When installing rod or cable probes in vessels without metal walls,
e.g. in plastic vessels, the measured value can be inuenced by
strong electromagnetic elds (emitted interference according to
EN 61326: class A). In this case, use a probe with coaxial version.
1 2
Fig. 5: Installation in plastic silo
1 Flange
2 Metal sheet
If possible, avoid sockets. Mount the sensor ush with the vessel top.
If this is not possible, use short sockets with small diameter.
Higher sockets or sockets with a bigger diameter can generally be
used. They simply increase the upper blocking distance. Check if this
is relevant for your measurement.
Type of vessel
Socket

15
4 Mounting
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
In such cases, always carry out a false signal suppression after instal-
lation. You can nd further information under "Setup procedure".
h
d
dh
DN40...DN150
>DN150... DN200 150
100
_
<
_
<
Fig. 6: Mounting socket
When welding the socket, make sure that the socket is ush to the
vessel top.
1 2
Fig.7:Socketmustbeinstalledush
1 Unfavourable installation
2 Socketush-optimuminstallation
Before beginning the welding work, remove the electronics module
from the sensor. By doing this, you avoid damage to the electronics
through inductive coupling.
Do not mount the instruments in or above the lling stream. Make sure
that you detect the product surface, not the inowing product.
Welding work
Inowingmedium

16
4 Mounting
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
Fig.8:Mountingofthesensorwithinowingmedium
The reference plane for the measuring range of the sensors is the
sealing surface of the thread or ange.
Keep in mind that a min. distance must be maintained below the refer-
ence plane and possibly also at the end of the probe - measurement
in these areas is not possible (dead band). The length of the cable
can be used all the way to the end only when measuring conductive
products. These blocking distances for dierent mediums are listed
in chapter "Technicaldata". Keep in mind for the adjustment that the
default setting for the measuring range refers to water.
The process tting must be sealed if there is gauge or low pressure in
the vessel. Before use, check if the seal material is resistant against
the measured product and the process temperature.
The max. permissible pressure is specied in chapter "Technical
data" or on the type label of the sensor.
Standpipes or bypass tubes are normally metal tubes with a diameter
of 30 … 200 mm (1.18 … 7.87 in). In measurement technology such a
tube corresponds to a coax probe. It does not matter if the standpipe
is perforated or slotted for better mixing. Lateral inlets with bypass
tubes also do not inuence the measurement.
Microwaves can penetrate many plastics. For process technical rea-
sons, plastic standpipes are problematic. If durability is no problem,
then we recommend the use of metal standpipes.
When the VEGAFLEX 81 is used in standpipes or bypass tubes,
contact with the tube wall must be avoided. We recommend for this
purpose a cable probe with centering weight.
Generally a spacer at the probe end is sucient for rod probes to
avoid contact to the tube wall. Depending on the tube diameter or
tube length, spacers can be also mounted in the centre of the tube.
With cable probes it is also possible to strain the cable.
Measuring range
Pressure
Standpipes or bypass
tubes

17
4 Mounting
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
Keep in mind that buildup can form on the spacers. Strong buildup
can inuence the measurement.
1
2 3
Fig. 9: Position of the spacer or centering weight
1 Rodprobewithspacer(PEEK)
2 Cableprobewithcenteringweight
3 Spacer(PEEK)onthegravityweightofacableprobe
Note:
Measurement in a standpipe is not recommended for extremely
adhesive products.
Instructions for the measurement:
• The 100 % point should not be above the upper tube connection
to the vessel
• The 0 % point should not be below the lower tube connection to
the vessel
• A false signal suppression with integrated sensor is generally
recommended to reach the maximum possible accuracy
If there is a danger of the cable probe touching the vessel wall during
operation due to product movements or agitators etc., the measuring
probe should be securely xed.
In the gravity weight there is an internal thread (M8), e.g. for an eye-
bolt (optional) - (article no. 2.1512).
Make sure that the probe cable is not completely taut. Avoid tensile
loads on the cable.
Avoid undened vessel connections, i.e. the connection must be
either grounded reliably or isolated reliably. Any undened change of
this requirement can lead to measurement errors.
In case of dicult installation conditions, the probe can be also
mounted laterally. For this purpose, adapt the rod with rod extensions
or bow-shaped segments.
Fixing
Rod extensions

18
4 Mounting
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
Let the probe length determine automatically by the instrument to
compensate the resulting running time changes.
The determine probe length can deviate from the actual probe length
when using bow-shaped segments.
Make sure that the rod of the probe is at least 300 mm (11.811 in)
away from the vessel wall
You can nd further information in the supplementary instructions of
the rod extension.

19
5 Connecting to power supply and bus system
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
5 Connecting to power supply and bus
system
5.1 Preparing the connection
Always keep in mind the following safety instructions:
• Connect only in the complete absence of line voltage
• If overvoltage surges are expected, overvoltage arresters should
be installed
The instrument requires an operating voltage of 8 … 30 V DC. Operat-
ing voltage and digital bus signal are carried on separate two-wire
connection cables.
The instrument is connected with standard two-wire, twisted cable
suitable for RS 485. If electromagnetic interference is expected which
is above the test values of EN 61326 for industrial areas, screened
cable should be used.
Use cable with round cross-section. A cable outer diameter of
5 … 9 mm (0.2 … 0.35 in) ensures the seal eect of the cable gland.
If you are using cable with a dierent diameter or cross-section,
exchange the seal or use a suitable cable gland.
Make sure that the entire installation is carried out according to the
Fieldbus specication. In particular, make sure that the bus is termi-
nated with suitable terminating resistors.
With plastic housing, the NPT cable gland or the Conduit steel tube
must be screwed without grease into the threaded insert.
Max. torque for all housings see chapter "Technicaldata".
With systems with potential equalisation, connect the cable screen
directly to ground potential at the power supply unit, in the connection
box and at the sensor. The screen in the sensor must be connected
directly to the internal ground terminal. The ground terminal outside
on the housing must be connected to the potential equalisation (low
impedance).
In systems without potential equalisation, connect the cable screen
directly to ground potential at the power supply unit and at the sensor.
In the connection box or T-distributor, the screen of the short stub to
the sensor must not be connected to ground potential or to another
cable screen. The cable screens to the power supply unit and to the
next distributor must be connected to each other and also connected
to ground potential via a ceramic capacitor (e.g. 1 nF, 1500 V). The
low frequency potential equalisation currents are thus suppressed,
but the protective eect against high frequency interference signals
remains.
5.2 Connecting
The voltage supply and signal output are connected via the spring-
loaded terminals in the housing.
Safety instructions
Voltage supply
Connection cable
Cable gland ½ NPT
Cable screening and
grounding
Connection technology

20
5 Connecting to power supply and bus system
VEGAFLEX 81 • Modbus and Levelmaster protocol
41828-EN-121112
The connection to the indicating and adjustment module or to the
interface adapter is carried out via contact pins in the housing.
Information:
The terminal block is pluggable and can be removed from the elec-
tronics. To do this, lift the terminal block with a small screwdriver and
pull it out. When inserting the terminal block again, you should hear it
snap in.
Proceed as follows:
1. Unscrew the housing cover
2. If an indicating and adjustment module is installed, remove it by
turning it slightly to the left.
3. Loosen compression nut of the cable entry
4. Remove approx. 10 cm (4 in) of the cable mantle, strip approx.
1 cm (0.4 in) of insulation from the ends of the individual wires
5. Insert the cable into the sensor through the cable entry
Fig.10:Connectionsteps5and6
6. Insert the wire ends into the terminals according to the wiring plan
Information:
Solid cores as well as exible cores with cable end sleeves are
inserted directly into the terminal openings. In case of exible cores
without end sleeves, press the terminal head with a small screwdriver;
the terminal opening is freed. When the screwdriver is released, the
terminal closes again.
You can nd further information to the max. wire cross-section under
"Technicaldata/Electromechanicaldata"
7. Check the hold of the wires in the terminals by lightly pulling on
them
8. Connect the screen to the internal ground terminal, connect the
outer ground terminal to potential equalisation
9. Tighten the compression nut of the cable entry. The seal ring must
completely encircle the cable
Connection procedure