Wiring diagrams for the Fieldbus Diagnostics application

Remove the USB cable from the Trex unit before connecting to a device.
The Trex unit draws approximately 12 mA from the fieldbus segment when it is online. (The Trex unit draws 0 mA when it is offline.) Ensure the power supply or barrier on the fieldbus segment has the capacity to provide this additional current when the Trex unit is online. If a heavily loaded fieldbus segment is drawing near the capacity of the segment’s power supply, connecting the Trex unit may result in loss of communication.

Power and connect to a FOUNDATION fieldbus device

To power a FOUNDATION fieldbus device, the Trex unit needs the FOUNDATION fieldbus Power Plug. When the Trex unit powers a device, it also provides two terminators and a power conditioner.

Warning: The Trex unit can power only one FOUNDATION fieldbus device in a bench setup.
  1. FOUNDATION fieldbus Power Plug

Connect to an externally-powered fieldbus segment

For small fieldbus segments, the power conditioner and terminators can be contained in a single wiring block.

Note: You can connect the Trex unit at any convenient place along the fieldbus segment (bus). In the field, this is typically done at the device or at the fieldbus junction box. The drawing below is one example.
  1. Terminators
  2. Power conditioner
  3. Fieldbus power supply
  4. Host system