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ADU71 User Manual
3.
The ADU71 STATUS LED
The ADU71 STATUS LED is a bi-colour ( Red/Green) led indicator used to identify the current status of the ADU71
USB connection.
The LED modes are;
RED
-ADU71 powered but not enumerated.
GREEN -ADU71 powered and enumerated by host computer.
OFF
-ADU71 disconnected from USB bus OR host computer has entered SLEEP mode.
The ADU71 can be connected to the USB bus via the enclosed 10' A-B USB cable. The cable provides both power
and communications connections to the ADU71. When first connected, the STATUS led will turn RED indicating
power is applied. For Windows operating systems, a message may flash on the screen indicating;
New hardware Found
ADU71 USB to Current Output Interface
Depending on the version of Windows, the host may prompt to search for a driver. Select,
Let Windows Search for a Driver
and click next.
After a few seconds, the STATUS led will turn green indicating enumeration is complete. The enumeration
process is completely transparent to the application program as the ADU71 is a USB HID class device. Enumeration
is completed by the Windows ( or other ) operating system standard USB HID drivers.
The ADU71 can be connected directly to the host hub or externally powered hubs.
Caution: ( Use of System Sleep ):
If the Windows ( or other ) operating system allows the host computer to enter
sleep mode, attached USB devices will be set to suspend mode. In this mode the power draw of the ADU71 drops
to less than 2.5mA ( USB2.0 Specification ) and the current loop output is put into high impedance mode. In
suspend mode the ADU71 Status LED is turned off. Once the host computer is revived from sleep mode, the
ADU71 status LED will turn to green and the output will have to be re-enabled by the host application. Ensure
system power settings are set such that the host computer does not enter sleep mode during normal operation.