VEGA VEGABAR 44 HART - Manual (Page 12)

12 VEGABAR 44 (HART ® )
3 Electrical connection
3.1 Connection instructions
The electronics in VEGABAR 44 requires a
supply voltage of 12 … 36 V DC. It is pro-
vided in two-wire technology, i.e. supply
voltage and current signal are led to the
terminals via the same two-wire connection
cable.
This external energy is provided via a sepa-
rate power supply unit:
- power supply unit, e.g. VEGASTAB 690
- processing unit with integrated DC current
source (e.g. active PLC input)
- VEGAMET 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 instruments meet this re-
quirement, and protection class II is therefore
ensured.
The external energy source must supply a
terminal voltage of at least 12 V to the trans-
mitter. The actual terminal voltage on the
transmitter depends on the following factors:
- output voltage of the external energy
source under nominal load.
- electrical resistances of the connected
instruments in the circuit (see Connected
instruments, load resistor).
Mounting, Electrical connection
2 Mounting
2.1 Mounting instructions
VEGABAR can be mounted in any position.
Cable entries must point downwards to avoid
moisture ingress. For this purpose, the hous-
ing can be rotated by 330° in relation to the
mounting part.
A seal, appropriate for connection, must be
used for mounting. This seal is either sup-
plied with VEGABAR or must be provided by
the customer.
2.2 Compensation of the atmos-
pheric pressure
On instruments for gauge pressure meas-
urement, the atmospheric pressure is com-
pensated via a breather facility integrated in
the housing.