More Information

About the problem

Some computers, primarily laptops, employ power conservation features that shut
off the communications port (serial port) within seconds after launching or
offloading a logger. The computer does this automatically without waiting for
the logger to be disconnected from the serial cable.

After launching a logger, the port may shut down which will cause the logger to
stop logging.  After offloading a logger, the port may shut down which will stop
the logger from switching to low power mode and will eventually result in a dead
battery.

Onset has fixed this problem by holding the serial port open (preventing the
port from powering down) until you verify that the cable has been disconnected.

Testing your computer for this problem.

Note: If you use a laptop to launch your loggers, run this test with and without
battery power.

1. Launch an Onset logger with your computer with an interval of ten seconds.
2. Click OK when prompted to remove the serial cable, but leave the cable
connected to the logger.
3. Wait at least one minute.
4. Disconnect the cable and check that the logger's LED is blinking every
two seconds.

If the logger's LED is not blinking, it means that the logger has stopped
logging.  Offload the logger and look at the data file.  Incomplete data files
typically contain only one data point if the serial port has shut down.  If your
data file is incomplete, then your computer (most likely) has the serial port
power problem.  To avoid serial port power problems, unplug the logger from the
serial cable each time you launch or offload a logger.

If the logger's LED is blinking, you do not have the serial port power problem.
 In this case, you can safely disable the Disconnect Logger dialog so that you
are not prompted to remove the serial cable every time you launch or offload a
logger.  To disable the warning: go to Edit/Preferences/Confirmation and clear
the "Show logger serial port UNPLUG Confirmations" item. (You can always change
it back later.)

We suggest that you always verify logger operation by checking that the LED is
blinking when launching any logger on any computer.