VSN730 System Monitor Product Manual
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18 -
Adding an ABB weather station
The VSN800 Weather Station is wired to the Primary RS-485 port on the data logger through a
surge protection device. The weather station can be connected directly to the System Monitor or
can be connected in a daisy-chain with other Modbus RTU devices. Power for the weather station
can be tapped from the +24VDC and DC COM landing blocks. The VSN800 can use the 24VDC
power from the VSN730, but 24VDC power is not required. The VSN800 can operate using power
in the range 10-30VDC.
1.
Connect shielded twisted-pair wire to the RS-485 terminals on the VSN800 Weather Station.
Use RS-485 data wire with one twisted-pair of conductors, one signal ground conductor, and a
shield with drain wire (Belden 3106A or equivalent). DO NOT USE CAT5/6 CABLE FOR THE
RS-485 DATA WIRE.
2.
Connect the other end of the shielded twisted-pair wire to the Citel surge protection device.
Use the table and figure below to make the proper connections.
Connections
Example VSN800 Weather
Station RS-485 Pin Label
Citel Connectors,
RS-485 Wiring
DIN Rail Connectors,
Weather Station Power
RS-485 Negative (-) RS-485 A(-)
D-
------
RS-485 Positive (+) RS-485 B(+)
D+
------
Signal Ground
RS-485 GND
Signal Common
------
Shield
RS-485 Shield
Shield
------
VDC Power Ground GND
------
24- (VDC-)
VDC Power
24VDC
------
24+ (VDC+)