Measurement Computing Personal Daq rev.6.0 - Manual (Page 39)

Personal Daq User’s Manual 878695 Hardware Setup 3-3
USB Hubs and Power Adapters
With the use of USB hubs you can connect up to 100 Personal Daq units to one PC. USB hubs can be of
the self-powered type, or of the USB-powered type. Both types of hubs are available from a variety of
vendors; however, if you encounter any difficulty in obtaining a USB hub, please contact your service
representative.
Power Adapters
− Power adapters, also referred to as auxiliary power packs, are required for some self-
powered hubs, and for Personal Daq modules that are powered from USB-powered hubs. In addition,
Personal Daq units will require the use of a power adapter when used with certain laptops.
When using a power adapter with your Personal Daq system, be sure to supply power
(from the adapter to the Personal Daq) before connecting the USB cable. This allows
Personal Daq to inform the host computer (upon connection of the USB cable) that the
unit requires minimal power from the computer.
Power adapters for use with Personal Daq have a current limit of 500 mA (min.) and a voltage range of
+6 to +16 Volts DC. These specifications are provided on the end-face of the Personal Daq.
If the computer does not recognize the Personal Daq unit, make sure the computer’s USB port is properly
enabled and is in good working order. If the computer still fails to recognize the Personal Daq, the use of a
power pack may be required. In United States use a TR-2 power pack, or equivalent. In Europe use a
TR-2E power pack, or equivalent. Both the TR-2 and the TR-2E provide 500 mA min, +6 to +16 VDC.
The use of certain notebook computers may require the use of a power adapter with
your Personal Daq.
USB-powered Hubs
− These hubs draw all power from the host USB connector’s power pins. The power
is used for hub internal functions and for the hub’s ports. Each port of a USB-powered hub must be
capable of supplying at least 100 mA.
Self-powered Hubs
− These hubs draw power from a source other than the host USB connector, with
exception that they may draw up to 100 mA from their upstream connection for hub internal functions.
The external power is used for hub internal functions and for the hub’s ports. Each port of a self-powered
hub must be capable of supplying 500 mA.