Instruction manual

Output Wiring
continued
RFT9739 Field-Mount Transmitter Instruction Manual 49
Output Wiring Startup TroubleshootingBefore You Begin Getting Started Mounting
Power-Supply and
Sensor Wiring
To connect the transmitter to a Bell 202 network, use RFT9739 terminals
17 and 18. See
Figure 5-23
.
• SMART FAMILY devices require a minimum loop resistance of
250 ohms. Loop resistance must not exceed 1000 ohms.
• Connect the mA outputs from each transmitter together so they
terminate at a common load resistor, with at least 250 ohms
impedance, installed in series.
Figure 5-23. Typical HART
®
network wiring
PV+
17
PV–
18
PV+
CN2-
Z30
PV–
CN2-
D30
4-20mA
4-20mA
24
DC
For optimum HART communication, make sure the output loop is single-point
grounded to instrument grade ground.
HART
Communicator,
ProLink PCI,
or AMS modem
RFT9739
field-mount
RFT9739
rack-mount
SMART
FAMILY
trans-
mitter
SMART
FAMILY
trans-
mitter
DC source required for
other HART 4-20mA
passive transmitters
IFT9701
R-Series
250 ohm
load