Vega VEGAPULS 61 - 5 Connecting to power supply and bus system; 5.1 Preparing the connection

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5 Connecting to power supply and bus system
VEGAPULS 61 • Modbus and Levelmaster protocol
41717-EN-160224
5 Connecting to power supply and bus
system
5.1 Preparing the connection
Always keep in mind the following safety instructions:
Warning:
Connect only in the complete absence of line voltage.
•
The electrical connection must only be carried out by trained
personnel authorised by the plant operator.
•
If overvoltage surges are expected, overvoltage arresters should
be installed.
The instrument requires an operating voltage of 8 … 30 V DC. Operat-
ing voltage and digital bus signal are carried on separate two-wire
connection cables.
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, screened
cable should be used.
Use cable with round cross section for instruments with housing and
cablegland.Toensurethesealeectofthecablegland(IPprotection
rating),ndoutwhichcableouterdiameterthecableglandissuitable
for.
Useacableglandttingthecablediameter.
Make sure that the entire installation is carried out according to the
Fieldbusspecication.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.
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.
Prior to setup you have to replace these protective caps with ap-
proved cable glands or close the openings with suitable blind plugs.
With plastic housing, the NPT cable gland or the Conduit steel tube
must be screwed without grease into the threaded insert.
Max. torque for all housings, see chapter "Technical data".
In systems with potential equalisation, connect the cable screen
directly to ground potential at the power supply unit, in the connection
Safety instructions
Voltage supply
Connection cable
Cable glands
Cable screening and
grounding