FB3000 RTU Instruction Manual
D301851X012
November 2023
64 I/O Configuration and Wiring
3.2.3 Analog Input Mode (HART Communications Disabled)
If you have an unused HART channel, you can use it as a 4-20mA analog input (AI current
mode).
In FBxConnect, you must Enable the 250-Ohm Termination Resistor and set the HART
Comm Mode to Disabled.
Figure 3-14 shows two examples for wiring a HART channel as a 4-20mA analog input. In
the figure, an externally powered current loop transmitter connects to Channel 1 and a
loop powered current loop transmitter connects to Channel 4.
Figure 3-14. Connecting 4mA to 20mA Analog Inputs to 3HART04 Channel (No HART
Communications)
4-20mA Analog Signal Loop
3HRT04 Module internal ground connections (for information only; not visible to
user)