User Manual

HOBO U12 Temp/RH/2 External Data Logger
2
2. Plug the small end of the USB interface cable into the
bottom of the logger as shown in the following diagram.
If the logger has never been connected to the computer before,
it may take a few seconds for the new hardware to be detected.
Use the logger software to launch and read out the logger.
Important: If you configure the logger to start with a
button start, be sure to press and hold down the button on
the front of the logger for at least three seconds when you
want to begin logging data.
Be sure to plug any external sensors (if applicable) into the
side of the logger before logging begins. Also select the
correct sensors and activate the external channels in the logger
software when configuring the launch. Important: If you
select an external channel, but do not plug the probe in,
false data will be recorded for that channel.
You can read out the logger while it continues to log, stop it
manually with the software, or let it record data until the
memory is full.
Refer to the software user’s guide for complete details on
launching, reading out, and viewing data from the logger.
Sample and Event Logging
The logger can record two types of data: samples and events.
Samples are the sensor measurements recorded at each
logging interval (for example, the temperature every minute).
Events are independent occurrences triggered by a logger
activity. Examples of events recorded asynchronously during
deployment include when the logger is connected to the host,
when the battery is low, the end of a data file once the logger
is stopped, and button pushes.
Press the button on the front of the logger for one second to
record an event. Both a button up and down event will be
recorded. This is useful if you want to mark the datafile at a
particular point. For example, if the logger is located in an
incubator, you might press the button each time the door is
opened.
The logger stores 64K of data, and can record up to 43,000
samples and events combined.
Operation
A light (LED) on the side of the logger confirms logger
operation.
The following table explains when the logger blinks during
logger operation:
When: The light:
The logger is logging
Blinks once every one to four
seconds (the shorter the logging
interval, the faster the light
blinks); blinks when logging a
sample
The logger is awaiting a
start because it was
launched in Start At
Interval, Delayed Start,
or Button Start mode
Blinks once every eight seconds
until launch begins
The button on the logger
is being pushed for a
Button Start launch
Blinks once every second while
pressing the button and then
flashes rapidly once you release
the button. The light then reverts
to a blinking pattern based on the
logging interval
Protecting the Logger
The logger can be permanently damaged by corrosion if it gets
wet. Protect it from condensation. If it gets wet, remove the
battery immediately and dry the circuit board with a hair dryer
before reinstalling the battery. Do not let the board get too hot.
You should be able to comfortably hold the board in your
hand while drying.
Note! Static electricity may cause the logger to stop
logging. To avoid electrostatic discharge, transport the logger
in an anti-static bag, and ground yourself by touching an
unpainted metal surface before handling the logger. For more
information about electrostatic discharge, visit our website at
http://www.onsetcomp.com/Support/support.html.
Using External Sensors
The external input channels have a switched 2.5 V output.
This signal can be used to power a sensor directly or it can
also be used to trigger an external circuit. External sensors
should draw no more than 4 mA total when powered. The
switched 2.5 V output turns on about 15 ms before the
external channels are measured and stays powered for 48 ms
after the external channels are measured, as shown in the
Channel 3
external input
Channel 4
external input
Light
Important: Press this
button for 3 seconds
when logger is
launched with Button
Start or press for 1
second to record an
event while logging
USB interface
cable plugged
into logger