Operating Instructions
VEGAWELL 71
Level and Pressure
p
Contents
Safety information ........................................................................ 2
Note Ex area ................................................................................ 2
1 Product description
1.1 Function and configuration .................................................. 3
1.2 Application features ............................................................. 3
1.3 Types and versions ............................................................. 3
2 Technical data
2.1 Data ....................................................................................... 4
2.2 Dimensions ........................................................................... 6
3 Mounting
3.1 Installation place ................................................................... 7
3.2 Mounting of the external connection housing .................... 7
3.3 Compensation of the atmospheric pressure ..................... 7
4 Electrical connection ................................................................ 8
Contents
5 Set-up .......................................................................................... 9
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.
2 VEGAWELL 71
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.
Product description
1 Product description
1.1 Function and configuration
The pressure transmitter is used for continuous level measurement of water or waste
water with low solid contents.
The hydrostatic pressure of the product
effects a capacitance change on the absolutely dry ceramic diaphragm of the measuring cell. The integral processing electronics
converts the capacitance changes on the
ceramic diaphragm into a pressure proportional current of 4 … 20 mA um.
Principle: Plate capacitor
The dry, ceramic-capacitive CERTEC®-measuring cell is manufactured of a new developed high resistance ceramic. A ceramic
diaphragm is fastened on to a ceramic basic
body by means of glass joint. Ceramic basic
body and diaphragm form the plates of a
capacitor.
The plate distance between the ceramic
body and the diaphragm is only 16 µm. The
diaphragm moves in this small range and
effects capacitance changes via the "variable
plate distance“ which are provided as measuring signal.
1.2 Application features
• Diameter of the transmitter 32 mm
• Absolutely dry
• Up to 150-times overload resistant
• Extreme long term stability
• High resistance, rugged up to 2,2 mm
thick ceramic
• Integral overvoltage protection
• Optionally Ex-approved Zone 1
(II 2G EEx ia IIC T4)
1.3 Types and versions
VEGAWELL 71 consists of:
- Fix mounted special cable with breather
capillaries
- Pressure transmitter with 4 … 20 mA-output signal and integral overvoltage protection
- Optional straining clamp or closing screw
A measuring system consists of:
- a pressure transmitter and a voltage supply (supply voltage 12 … 36 V DC) or
- a pressure transmitter and a VEGA-signal
conditioning instrument.
Up to 150-times overload resistant
In case of overload, the 16 µm wide gap
between ceramic basic body and the diaphragm is completely overcome. The diaphragm fits flush to the ceramic basic body
which absorbs the overpressure forces. The
overload therefore does not cause any further "bending“ of the diaphragm and the
overpressure forces are absorbed up to the
stated limits without problems.
VEGAWELL 71 3
2 Technical data
2.1 Data
Power supply
Supply voltage 12 … 36 V DC
Permissible load (dependent on the supply voltage)
Ω
900
600
300
12
18 24 30 36
Measuring ranges
Measuring range and overload in bar Measuring range Overload
0 … 0,1 15
0 … 0,2 20
0 … 0,4 30
0 … 1,0 35
0 … 2,5 50
0 … 5,0 65
0 … 10,0 90
0 … 20,0 130
Technical data
Supply voltage
in V
Output signal
4 … 20 mA-current signal; two-wire technology (supply and measuring signal via a twowire line)
Meas. accuracy (relating to the nominal measuring range)
Characteristics linear
Deviation in characteristics < 0,5 %
Long term stability of the zero signal 1)< 0,1 %/2 years
Hysteresis or repeatability < 0,02 %
Average temperature coefficient of the
zero signal
1)
Acc. to IEC 770
2)
In the compensated temperature range of 0°C … 80°C; reference temperature 20°C
4 VEGAWELL 71
2)
< 0,20 %/10 K
Technical data
Ambient conditions
Product temperature -40°C … +60°C
Storage and transport temperature -40°C … +60°C
Protection IP 68
Protection class III
Overvoltage category III
Materials
Diaphragm sapphire-ceramic
®
Closing screw stainless steel 1.4571
Straining clamp St galvanised
Suspension cable PE
Cable bushing CSM
Transmitter housing stainless steel 1.4571
Seal of the measuring cell Viton
Transmitter protection PE-plastic coating or
stainless steel 1.4571-protective cover
Weights
Basic weight approx. 0,7 kg
Suspension cable approx. 0,1 kg/m
Closing screw approx. 0,4 kg
Straining clamp approx. 0,2 kg
Connection line
Two-wire suspension cable, screened, with steel suspension cable and capillaries for pressure compensation
CE-conformity
VEGAWELL 71 pressure transmitter meets the protective regulations of EMVG (89/336/
EWG) and NSR (73/23/EWG). The conformity has been judged acc. to the following standards:
EMVG Emission EN 50 081 - 1: 1992
Susceptibility EN 50 082 - 2: 1995
NSR EN 61 010 - 1: 1993
VEGAWELL 71 5
2.2 Dimensions
without fastening Straining clamp Closing screw
Technical data
52
226
Ø 8
175
R 11
49
25
246
41
14
266
SW 30
G 1½ A
Ø 32
Ø 32
Ø 36
6 VEGAWELL 71
Mounting
3 Mounting
3.1 Installation place
Please note when installing the
pressure transmitter, that the
instrument is mounted in a
position without turbulences
and material inflow. Otherwise,
we recommend the use a
sounding or a conducting pipe
to avoid lateral movement of the
pressure transmitter (left pressure transmitter in the figure).
3.2 Mounting of the external connection housing
To avoid condensation, note that no humidity
can penetrate into the breather capillaries.
With the external VEGABOX 01 connection
housing with breather facility, this will be
ensured. In case of vertical wall mounting, the
cable entry must point downwards so that
humidity cannot penetrate through the cable
entry.
External connection
housing VEGABOX 01
4…20 mA
to processing
unit and
supply
voltage
Deep well measurement
3.3 Compensation of the atmospheric pressure
The compensation of the atmospheric pressure is made via the breather capillaries of
the special cable in the external connection
housing.
Please make sure that you cut the breather
capillaries carefully and do not bend them.
Breather capillaries
Steel suspension cable
Measuring lines
br +
bl –
Screen
VEGAWELL 71 7
4 Electrical connection
VEGAWELL 71 with straining clamp
External connection housing
VEGABOX 01
Electrical connection
4…20 mA
4…20 mA
to processing unit
and supply voltage
4…20 mA
standard two-wire
PE-cable with breather
capillaries
cable
Interferences and overvoltages must often
be expected in an industrial environment ,
especially in wells and sewage plants where
overvoltages due to lightning strikes are
possible. The pressure transmitters are
therefore equipped with an integral
overvoltage protection.
Terminal coor dination and connection to VEGABO X 01 external connection housing
VEGABOX 01
Zum Anschluß an
For connection to
Druckmeßumformer mit
pressure transmitters with
analogem Ausgangssignal
analog output
1
Pressure transmitter with direct
cable outlet
Breather capillaries
Suspension
cable
+
–
Screen
231011 12
TRANSMITTER
VEGABOX 01
–
+
–
+
+
For supply or to the processing
system (4 … 20 mA,
–
12 … 36 V DC)
+
Control instrument
–
(4 … 20 mA-measurement)
8 VEGAWELL 71
Set-up
5 Set-up
Connection possibilities
The electronics of the VEGAWELL pressure
transmitter requires a supply voltage of
12 … 36 V DC. Connect the pressure transmitter to the supply voltage. The pressure
transmitter then takes within its measuring
range, a pressure proportional current between 4 … 20 mA.
The max. permissible load depends on the
height of the supply voltage (see diagram in
chapter 2´ Technical data).
Power supply unit
(e.g. VEGASTAB)
~
VEGAWELL 71
br
1
bl
2
+
4 … 20 mA
–
+ –
12 … 36 V DC
Processing unit active
VEGAWELL 71
br
1
bl
2
VEGAWELL 71
1
br
bl
2
+
4 … 20 mA
–
Power supply unit
(e.g.VEGASTAB)
~
+ –
+
4 … 20 mA
–
(VEGAWELL is powered)
+
–
12 … 36 V DC
Processing unit passive
(VEGAWELL is powered by the
external power supply unit)
+
–
12 … 36 V DC
VEGAWELL 71 9
Set-up
Fault finding
If the level does not correspond to the indicated measured value, first of all the pressure compensation, and then the electronics
of the measuring system should be checked.
Checking of the pressure compensation
Open the external connection housing
(VEGABOX 01). The measured value must
not change at, a steady level. If the measured value changes, the required compensation of the atmospheric pressure is not
guaranteed (influence of the measured
value!).
In this case, the breather facility in the external connection housing and the breather
capillaries must be checked.
Checking of the measuring circuit
In measuring systems with overvoltage arresters, these should first be checked for
interruption or shortcircuit.
V
+
–
mA
to processing
unit and supply
voltage
Voltage
The supply voltage on the connection of the
pressure transmitter must be 12 … 36 V DC.
Current
Initial current with uncovered diaphragm of
the pressure transmitter: approx. 4 mA.
Meas. current during operation: 4 … 20 mA.
Meas. line interrupted: current = 0 mA.
Exceeding or decreasing of meas. range:
3 … 4 mA (decreasing of meas. range),
20 … 22 mA (exceeding of meas. range).
Pressure transmitter defect or shortcircuit:
current > 23 mA.
VEGAWELL 71
10 VEGAWELL 71
Notes
VEGAWELL 71 11
VEGA Grieshaber KG
Am Hohenstein 113
77761 Schiltach/Germany
Phone +49 (0) 7836 50-0
Fax +49 (0) 7836 50-201
E-Mail info@de.vega.com
www.vega.com
ISO 9001
All statements concerning scope of delivery, application, practical
use and operating conditions of the sensors and processing systems correspond to the latest information at the time of printing.
Technical data subject to alterations
2.17 013 / June 2001
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