Enable Or Disable The Internal Resistors - Emerson AMS Trex User Manual

Field Communicator application
Figure 3-25:
A.
For 4-wire transmitters, the Trex unit must be connected in parallel. In the diagram below,
the Trex internal resistor is enabled in the HART terminals.
Figure 3-26:
A.
3.11.1

Enable or disable the internal resistors

If the Trex unit is powers the transmitter, there is no prompt/option to enable or disable
the internal 167 Ohm resistor. The Trex unit automatically applies the resistor when you
enable power to a transmitter from the device connection wizard.
76
Connection for using the Trex internal resistor for an externally-
powered 2-wire transmitter
Voltage source
Connection for using the internal resistor for a 4-wire transmitter
Voltage source
User Guide