Expert’s answer: Fieldbus diagnostics with AMS Trex Communicator

The AMS Trex communicator brings a lot of new tricks and tools to the table. Most noteworthy, is Emerson Automation’s decision to have Fieldbus Diagnostics already integrated with the AMS Trex. The idea is the FF diagnostic is given the chance to run a diagnostic on the Fieldbus segments as well as the device. You can isolate the devices and parts with problems by troubleshooting with the AMS Trex.

With any network there is always a chance for certain problems like grounding issues, water getting into cables and loose wires to arise. Therefore, the diagnostic tool in the Foundation Fieldbus network is a good way to discover these problems. Furthermore, the AMS Trex will alert you with a message if these sort of issues occur.

The Foundation Fieldbus Diagnostic allows you to measure particular ranges of information:

DC voltage:
  • -34 to 34 volts
  • Low-frequency (870 Hz – 9 KHz)
  • in-band frequency (9 KHz – 39 KHz)
  • high-frequency noise (39 kHz – 100 kHz)
Fieldbus signal level:
  • 100 – 1200 mV (peak-to-peak)

The Fieldbus Diagnostic home screen has a good visualization of the DC Voltage, Noise, and signal information. You can see more detailed information by clicking on each option individually. There is a complete breakdown in the AMS Trex manual explaining the status readings: good, bad, check and inactive. Therefore, I recommend you know exactly what each status means. Since you’re going to see the same descriptions to the Fieldbus signal status note, also be sure to know the meaning behind the descriptions “in the range for all nodes”, “signal low on all devices”, “signal high on most devices” and so on.

Furthermore, you can see the noise spectrum following the spectrum ranges. Since the readings are visual, like green meaning good, they are easy to analyze and understand.

Lastly, lets answer the question. The AMS Trex provides you with a lot of relevant information about the Fieldbus network and can be used as your primary check tool.

Finally, for more information, click on the video below for general information about the AMS Trex Communicator.

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