Onset Computer Corporation
HOBO U14
9
User’s Guide
Low Battery Alarm
Select the
Battery Alarm
checkbox to enable the Battery Alarm, which will trigger if the battery drops to 0%.
Alarm Reset
You can select when the alarm will be deactivated:
•
Host has re-launched logger
•
Sensor reading has returned within limits
Set Relay Contact
If you are using an external device that will be triggered by an alarm (such as a Remote Alarm or Automatic Dialer), set the desired
default relay contact state.
•
Normally Closed (default) - Relay opens during an alarm condition
•
Normally Open - Relay closes during an alarm condition
The ARA Remote Alarm can be set to Normally Closed or Normally Open (see remote device User’s Manuals for more details).
NOTE
: The AVD-45 Automatic Dialer requires the logger’s contacts to be set to Normally Closed.
Avoiding Unintended Relay Activation
In some applications, the environment in which the logger is launched is in immediate violation of the desired alarm limit and will cause
an unintended opening or closing of the contact relay. For example, setting an upper alarm limit of +32°F for a freezer application and
then launching the logger in a room at room temperature will cause an immediate alarm trigger.
In this situation, enable a Delayed Launch or select a number of samples that will result in a long enough delay to allow time to
transport, mount, and stabilize the logger in the desired location.
Other causes of invalid alarms would be freezer doors being opened frequently or defrost cycles. To avoid these, set the number of
samples to allow for small periods of time where the value is outside the range, but where the alarm will not be tripped unless the value
is outside the range for a significant number of samples.
Testing the Relay Alarm
Use the
Test
Set Alarm
button to test the relay alarm function. When you click the
Test
Set Alarm
button, the logger will activate the
alarm and change the condition of the contact closure.
When you click the
Test
Set Alarm
button, it changes to the
Test
Clear Alarm
button. Click the
Test
Clear Alarm
button to
deactivate the alarm.
NOTE
: When testing the alarm with the AVD-45 Automatic Dialer, Onset recommends that you maintain the alarm for up to 7 minutes
to ensure that the AVD-45 Automatic Dialer completes its dial-out sequence (see AVD-45 Automatic Dialer User’s Manual for details).
Summary of Contents for HOBO U14
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