VEGA WELL71 User Manual

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