Connecting To Power Supply And Bus System; Preparing The Connection - Vega VEGADIF 85 Operating Instructions Manual

Safety instructions
Voltage supply
Connection cable
Cable glands
VEGADIF 85 • Modbus and Levelmaster protocol
5 Connecting to power supply and bus
system
5.1

Preparing the connection

Always keep in mind the following safety instructions:
•
Carry out electrical connection by trained, qualified personnel
authorised by the plant operator
•
If overvoltage surges are expected, overvoltage arresters should
be installed
Warning:
Only connect or disconnect in de-energized state.
The operating voltage and the digital bus signal are routed via sepa-
rate two-wire connection cables.
The data for power supply are specified in chapter " Technical data".
Note:
Power the instrument via an energy-limited circuit (power max. 100 W)
acc. to IEC 61010-1, e.g.
•
Class 2 power supply unit (acc. to UL1310)
•
SELV power supply unit (safety extra-low voltage) with suitable
internal or external limitation of the output current
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, shielded
cable should be used.
Use cable with round cross section for instruments with housing and
cable gland. Use a cable gland suitable for the cable diameter to
ensure the seal effect of the cable gland (IP protection rating).
Make sure that the entire installation is carried out according to the
Fieldbus specification. In particular, make sure that the bus is termi-
nated with suitable terminating resistors.
Metric threads:
In the case of instrument housings with metric thread, the cable
glands are screwed in at the factory. They are sealed with plastic
plugs as transport protection.
Note:
You have to remove these plugs before electrical connection.
NPT thread:
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
free openings for the cable glands are therefore covered with red dust
protection caps as transport protection.

5 Connecting to power supply and bus system

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