Vega D81 Hydrostatic pressure transmitter Bedienungsanleitung PDF herunterladen (Seite 19)

Pressure transmitter D81 19

Electrical connection

3 Electrical connection

3.1 Connection instructions

The electronics in the pressure transmitter

requires a supply voltage of 12 … 32 V DC. It

is designed in two-wire technology, i.e. the

supply voltage and the digital output signal

are led via the same two-wire cable to the

terminals.

This external energy is provided via a sepa-

rate power supply unit, e.g.:

- power supply unit VEGASTAB 690

- processing unit with integrated DC voltage

source (e.g. active PLC input)

- VEGAMET, VEGALOG or VEGADIS 371

Make sure that the external energy source is

reliably separated from the mains circuits

acc. to DIN VDE 0106, part 101. The above-

mentioned VEGA devices meet this require-

ment and protection class III is therefore

guaranteed.

The external energy source must provide a

terminal voltage of at least 12 V on the trans-

mitter. The actual terminal voltage on the

transmitter depends on the following factors:

- output voltage U

H

of the external energy

source under nominal load.

- electrical resistance of the connected in-

struments in the circuit (see connected

instruments, load resistance).

Note the following instructions for electrical

connection:

- Connection must be made according to the

country-specific installation standards (e.g.

in Germany acc. to the VDE regulations).

- The terminal voltage must not exceed 36 V,

to avoid damage to the electronics.

- The electrical connection must have a pro-

tective measure against polarity reversal.

- Connection of Ex sensors only by qualified

personnel.

- The wiring between pressure transmitter

and power supply can be made with

standard two-wire cable.

- If strong electromagnetic interference is

expected, screened cable is recom-

mended. The screening must be done on

both ends. Note the installation regulations

for use in Ex areas.

- In case of overvoltages, we recommend

the use of pressure transmitters with inte-

grated overvoltage protection or the instal-

lation of VEGA overvoltage arresters.

- In the cable entry, a seal correctly fitting the

cable should be used.

Safety information for Ex applications

As a rule, do all connecting work in the com-

plete absence of line voltage. Always switch

off the power supply before you carry out

connecting work on the sensors. Protect

yourself and the instruments.

Qualified personnel

Instruments used in Ex areas must be in-

stalled only by qualified personnel. The quali-

fied personnel must observe and understand

the mounting regulations and the supplied

type approval certificates and conformity

certificates.

If an instrument is used in hazardous areas,

the respective regulations, conformity certifi-

cates and type approvals of the sensors,

separators or safety barriers must be noted

(e.g. DIN VDE 0165).

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