Emerson AMS Trex Device Communicator User Manual page 133

User Guide
4.5
User Guide
1.800.561.8187
Wiring diagrams for the Loop Diagnostics
application
CAUTION
Remove the USB cable from the Trex unit before connecting to a device.
WARNING
• Do not connect lead sets to the HART and HART + pwr terminals at the same time. If
the lead sets are connected to devices, this increases the chance of wiring mistakes and
could create a short in the HART loop.
• Do not add any external power to the device when the Trex unit is powering the device.
This can blow a fuse inside the Trex unit. The repair/replacement will need to be
completed at an authorized service center. Ensure the device is disconnected from the
loop/segment and no other wires are connected to the device before providing power
from the Trex unit.
• The Trex unit cannot power a 4-wire device. Do not connect Trex unit to the power
terminals of a 4-wire device. This can blow a fuse inside the Trex unit. The repair/
replacement will need to be completed at an authorized service center.
• Do not connect the mA terminals (ammeter) in parallel with a powered 4-20 mA
current loop. Ammeters have low resistance. This can disrupt the loop and cause
devices to report incorrect values or positioners to move unexpectedly.
• Do not connect the mA terminals on the Trex unit to a power supply that is not current
limited to 250 mA. This can blow a fuse inside the Trex unit. The repair/replacement
will need to be completed at an authorized service center.
www.
Loop Diagnostics application
information@itm.com
.com
September 2021
133