Advertisement
a.
Enable Sensor Alarms. To enable a sensor alarm, select the desired sensor in the Channel box, and then select the
check box for the High Alarm and/or the Low Alarm. Enter a value to define the alarm threshold. You can enter a
value in the box or use the sliders. (If you enter values manually, the software may adjust them slightly to the
nearest values supported by the logger.) You can also set the number of samples (30 seconds per sample) that must
be displayed before the alarm will be triggered.
b. Set Number of Samples. To avoid unintended activation of the relay contact, set the number of samples to allow
for anticipated breaches of the alarm threshold. If the alarm is tripped and the number of samples is set to more
than 1, the LCD will indicate Alert Delayed. If the measurement is still out of range when the number of samples is
reached, the relay contact will be activated.
Note about 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.
c.
Low Battery Alarm. Select the Battery Alarm checkbox to enable the Battery Alarm, which will trigger if the battery
drops to 0%.
d. Alarm Reset. Select whether the alarm will be deactivated when the Host has relaunched the logger or when the
sensor reading has returned within limits.
e. 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 to either Normally Closed (relay opens during an alarm
condition, which is the default) or 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.
f.
Test 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).
8. Click the Launch button in HOBOware to launch the HOBO U14. NOTE: If you remove the external sensor on the U14‐
002 model after logging starts, you will need to relaunch the logger if you reconnect a sensor.
9. Disconnect the HOBO U14 from the computer by unplugging the USB cable.
10. Transport the logger to deployment site.
11. Mount the logger. The HOBO U14 is designed for a non‐condensing, non‐corrosive environment. Make sure the logger
is installed in a location where it will remain dry. Some of the external sensors can be placed in harsher environments
(see the sensor manual for specifications).
a.
Mark the wall for the placement of the two mounting screws 2.5 cm (1 inch) apart (vertically).
b. Screw in mounting screws, leaving a gap between the wall and the head of the screw of about 0.5 cm (3/16 in.).
c.
Attach logger by aligning it with the screws, and then push in and down to lock in place.
12. If you have an External Sensor model (U14‐002), mount the External Sensors (see the sensor user manual).
HOBO U14 Data Logger User Manual
6
Advertisement
