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Reference Manual
00809-0100-4738, Rev DA
May 2006
Rosemount 3095FB
2-18
Figure 2-13. Field Wiring Connections
Inductive-based transient protectors, including the Rosemount 470, can
adversely affect the output of the 3095FB transmitter. Do not use the
Rosemount 470 for transient protection with the 3095FB. If your application
requires transient protection, install the Transient Protection Terminal Block
(Section 5: Troubleshooting).
Signal Wiring Grounding
Do not run signal wiring in conduit or open trays with power wiring, or near
heavy electrical equipment. You may ground the signal wiring at any one point
on the signal loop, or leave it ungrounded. The negative terminal of the power
supply is a recommended grounding point. Device must be properly grounded
or earthed according to local electric codes.
Power Supply
The transmitter requires between 7.5 and 30 V dc to operate and provide
complete functionality. The dc power supply should provide power with less
than 2% ripple.
RS-485 Bus
•
The 3095FB does not provide electrical isolation between the RS-485
bus and the transmitter power supply.
•
Maintain a bus topology and minimize stub length.
•
Figure 2-14 identifies multidrop wiring topology. Up to 32 devices may
be wired on one RS-485 bus.
•
The RS-485 bus needs to be terminated once at both ends, and should
not be terminated elsewhere on the bus. Setting the 3095FB AC
termination (AC) switch to ON (see page 2-11) is one method to
provide AC bus termination.
NOTE
The RTU may already provide one RS-485 bus termination.
User-Provided
Power Supply
RS-485 Bus
-
+
A
B