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3.4.2 Connection to USB-powered Hub
In this example, two OM-DAQ-USB-2401s are connected by cable to individual
ports of a single USB-powered hub. Since the hub receives all its power from
the computer's USB, the hub cannot supply adequate power to the DAQ units.
Because of this aspect of insufficient power, each unit is connected to its own
power adaptor.
POWER
ADAPTER
POWER
ADAPTER
3.4.3 Connections to Self-Powered and USB-powered Hubs
This example illustrates a system that makes use of four DAQ units and two
different style USB hubs. Two DAQs are connected by cable to individual ports
of a self-powered USB hub. In addition, the self-powered hub is connected to a
downstream USB-powered hub, which is also connected to two DAQ units.
Notice that the DAQ units connected to the self-powered hub have no adaptors
connected to them. This is because the hub receives external power (in addition
to the PC supplied USB power), which is capable of supporting the downstream
devices connected directly to it. In comparison, the three OM-DAQ-USB-2401s
connected to the USB-powered hub each require their own power adaptor. As
in example 3.4.2, the power adaptors used must be capable of supplying at least
500 mA and have a voltage rating of +7.5 to +12 Vdc.
USB
HUB
Figure 3-4. Connection to USB-Powered Hub
The power adaptors used must be capable of supplying at
least 500 mA and have a voltage rating of +7.5 to +12 Vdc.
USB
NOTE:
3
Hardware Setup
3-5
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