Measurement; Datalogging - Observator Instruments Diff-Automatic User Manual

3.2 Measurement

The DIFF starts to measure immediately once the option is selected from the menu. Make sure that the
following is prepared before measuring:
Closed doors and windows, the wind can create pressure waves that influence the measurement.

Put the square opening of the DIFF against the vent. When sure that the vent is fully covered the
measurement can be started. The measurements can be faulty when the measurement is started
before the DIFF is in place.

The DIFF will start with a pre-measurement. You can hear the motor starts running. The pre-
measurement will be followed by the final measurement.

Wait until the measurement is completed. The measurement can take tens of seconds. The
display will show the instantaneous flow and temperature value. This value is not reliable
because the DIFF is still compensating the measurement.

There will sound a beep when the measurement is finished. The value shown on the display is
the measured value. You can remove the DIFF from the vent.
Supply
Airtemp 24.5˚C
Airflow [M3/H]
+47.6
The plus sign indicates that an air inlet is being measured. It is also indicated as SUPPLY on the upper
left of the display.
A negative sign indicates that an air exhaust is being measured. It is also indicated as EXHAUST on the
upper left of the display.
The battery status is indicated by the blocks on the upper right of the display. It is recommended to
charge and/or replace the batteries when the battery status reaches the value of one block.
The air temperature of the air flowing through the DIFF is shown below the battery indication.
You can return to the menu by pressing the selection button. The measured value won't be available
anymore.
Comments:
The motor can reach a RPM of thousands of rounds per minute, and will create some sound. This can
create a high pitched tone caused by the motor control, which is normal.
Measurement duration:
The duration of the measurement depends on the amount of airflow going through the DIFF. The DIFF
will measure faster when the airflow is higher. The reason for this, is that the accuracy may be lower with
higher airflows.

3.3 Datalogging

We refer to chapter 7 for more information.
Version: 12.6 EN
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Date: 22-09-2020
User Manual Diff
AT-DIFF
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