Emerson 475 User Manual page 42

3-8
Figure 3-5 shows how to connect the optional 250 ohm resistor. Attaching a resistor is
necessary if less than 250 ohms resistance is present in the HART loop.
Figure 3-5. Connecting with a 250 Ohm Resistor
HART Device
–
+
To temporarily install the optional 250 ohm load resistor:
1. Insert the load resistor into the lead set jacks.
2. Open the loop to allow connection of the resistor in series in the loop.
3. Close the loop using the lead set connectors.
Figure 3-6 shows how to connect the 475 Field Communicator directly to the
communication terminals on a wireless device.
Figure 3-6. Connecting to a wireless device
Wireless Device
+
Power
Supply
–
Optional 250-Ohm
Load Resistor
Battery
Communication Terminals
HART Functionality