Emerson USB Fieldbus Interface, User Manual

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2.3 Power modes
The USB Fieldbus Interface is capable of working in two power modes:
• Mode 1 - The interface does not supply power to the connected fieldbus
device or segment. The fieldbus device or segment is powered by an
external source.
Mode 1 is the default.
• Mode 2 - The interface powers the connected fieldbus device or segment
and no external power is needed.
The interface is capable of powering multiple devices on a fieldbus
segment through an external USB hub. It can provide current of up to 85
mA (typically sufficient for three or four fieldbus devices on the same
segment).
You can configure Mode 2 using the Fieldbus Interface Configuration
utility. For more information, see
Section 4.2 .
WARNING!
Choose only one power mode. Never attempt to use two power sources at the same time. Doing so
can disrupt communications and may compromise automation safety.
May 2014 User's Manual
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