VEGA VEGAMET 625 - Manual (Page 13)

13
5 Connecting to power supply
VEGAMET 625 • Double channel HART
28970-EN-130701
2. Connect sensor cable to terminal 1/2 (active input) or 3/4 (passive
input), provide a screening
3. When using several sockets, loop the power supply by means of
bridges
4. Connect power supply (switched off) to terminal 17 and 18
5. If necessary, connect relays or other outputs
6. Insert VEGAMET 625 into the plug-in socket and screw it down
tightly
Note:
If the addressing of the sensors has not yet been carried out, only one
sensor must be connected. Addressing (see chapter "Setup") of the
first sensor can then be carried out. Afterwards, the first sensor must
be disconnected again and the next sensor connected and provided
with an address. Then all sensors can be connected and setup can
be started.
Before setting up Ex versions, make sure the Ex separating chamber
is plugged on the left housing side (above the sensor terminals). The
pins for type and Ex coding must also be inserted correctly.
Information:
•
On the active input (terminal 1/2), VEGAMET 625 provides power
for the connected sensors. Power supply and measurement data
are transmitted over the same two-wire cable. This mode is pro-
vided for connection of measuring transducers without separate
operating voltage (sensors in two-wire version).
•
On the passive input (terminals 3/4), the sensors are not supplied
with energy - only the measured value is transmitted. This input is
for instruments with their own separate operating voltage (sensors
in four-wire version or separators such as VEGATRENN 149). On
a VEGAMET 625 in Ex version, the passive input is not available
due to approval/technical reasons.
Note:
VEGAMET 625 is designed for connection of two HART sensors.
Because they are accessed via different addresses in the HART
multidrop mode, both sensors are connected to the same sensor
input. These are either terminals 1/2 (active input) or terminals 3/4
(passive input). Simultaneous mixed operation on active and passive
input is not possible. The measured value transmission is carried out
via the digital HART signal. An analogue 4 … 20 mA transmission is
not possible. Because this is a digital bus system, only one two-wire
cable should lead to the two sensors. A distributor can be connected
directly in front of the sensors. As an alternative, the connection to
the next sensor can be continued via the second cable entry in the
sensor housing. The addressing of the sensors should be carried out
before connection, see chapter "Set up".