5 connecting to the bus system, 1 preparing the connection, 5connecting to the bus system – VEGA VEGAPULS 62 (≥ 2.0.0 - ≥ 4.0.0) Foundation Fieldbus Approval according to LPR radio standard User Manual
Page 25
5
Connecting to the bus system
5
.1 Preparing the connection
Always keep in mind the following safety instructions:
l
Connect only in the complete absence of line voltage
l
If voltage surges are expected, install overvoltage arresters
The instrument requires a operating voltage of 9 … 32 V DC.
Operating voltage and the digital bus signal are carried on the same
two-wire connection cable. Power is supplied via the H1 power supply.
Connection is carried out with screened cable according to Fieldbus
specification.
Use cable with round cross-section. A cable outer diameter of 5 … 9 mm
(0.2 … 0.35 in) ensures the seal effect of the cable gland. If you are
using cable with a different diameter or cross-section, exchange the
seal or use a suitable cable gland.
Make sure that the entire installation is carried out according to the
Fieldbus specification. In particular, make sure that the bus is
terminated with suitable terminating resistors.
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"
Make sure that the cable screening and ground is executed according
to the Fielbus specification. If electromagnetic interference is expected
which is above the test values of EN 61326-1 for industrial areas, we
recommend to connect the cable screen on both ends to ground
potential.
In this case with systems with potential equalisation, connect the cable
screen directly to ground potential at the power supply unit, in the
connection box and at the sensor. The screen in the sensor must be
connected directly to the internal ground terminal. The ground terminal
outside on the housing must be connected to the potential equalisation
(low impedance).
In systems without potential equalisation with cable screening on both
sides, connect the cable screen directly to ground potential at the
power supply unit and at the sensor. In the connection box or T-
distributor, the screen of the short stub to the sensor must not be
connected to ground potential or to another cable screen. The cable
screens to the power supply unit and to the next distributor must be
connected to each other and also connected to ground potential via a
ceramic capacitor (e.g. 1 nF, 1500 V). Low-frequency potential
equalisation currents are thus suppressed, but the protective effect
against high frequency interference signals remains.
Safety instructions
Voltage supply
Connection cable
Cable gland ½ NPT
Cable screening and
grounding
VEGAPULS
62 • Approval according to LPR radio standard
25
5 Connecting to the bus system
41721
-EN
-120301