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7-3
Rosemount Tank Radar REX
Chapter 7 Bus Modems
Installation Manual
308014EN, Edition 4
May 2013
7.1.2 Power Supply
Use adapter 90-264 V ac/9 V dc 1.5 A for RS232 communication.
DO NOT use external power supply when the modem is connected to
the USB port. The USB interface itself supports power to the FBM2180
modem.
Figure 7-3. Power supply for RS232
7.1.3 TRL/2 Bus
Use single twisted preferably shielded pair cable. Individual shielding is
mandatory if parallel buses run in the same cable. Polarity independent.
Recommended wiring length:
Figure 7-4. TRL/2 Bus terminal
Cable dimension Maximum Length
AWG 20 (0.50 mm
2
)
3000 m
AWG 18 (0.75 mm
2
)
4000 m
Power supply (polarity independent)
(RS 232 communication only)
FBM2180_Back.eps
TRL/2 Bus
FBM2180_Back.eps