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pressure whatsoever, and during the second 10 seconds there was 50 Pa, then the gauge will average that
to 25 Pa. The rule of thumb here is to wait for at least double the time average period before a reading is
taken.
[Time Avg] exercise to practice reducing the effects of wind
1. Use a fan to create an air stream.
2. Set Time Averaging to “1 s”.
3. Place a tube, connected to the positive port, in the path of the air stream.
4. The gauge will display a pressure that fluctuates. Adjust the "wind" speed until the gauge is
reading between 2 and 5 Pa.
5. Adjust Time Averaging to 20 seconds.
6. Notice that after 20 seconds, the gauge reading fluctuates significantly less.
8.9.3. Let Time Averaging take effect before making readings
While the Time Averaging feature is useful to help minimize the effects of wind, it can also cause problems
if not used correctly. Whenever Time Averaging is on, it is important to wait at least twice the time
averaging period before taking a reading.
To learn how Time Averaging can cause error
1. Create a pressure on the positive port of Channel A (Input).
2. Set Time Averaging to one minute.
3. Wait until the pressure reading becomes stable. After one minute, Channel A should display
the created pressure.
4. Remove the tube from Channel A, eliminating the pressure.
5. Notice that the gauge continues to display a pressure on Channel A, which slowly decreases.
After one minute, the gauge should display no pressure difference.
If a reading is taken from the gauge before the full time averaging period has passed, then the displayed
pressure may not be accurate.
8.9.4. Use Baseline feature to reduce the effects of a constant wind
The [Baseline] feature can be used to minimize the effects of Bias Pressures, including that caused by wind
if the wind is relatively constant. This will reduce remove the bias caused by constant wind from the
measurements but will not help with the fluctuating nature of wind which is the biggest issue.
[Baseline] exercise to practice minimizing the effects of wind
1. Use a fan to create an air stream that causes between 2 and 5 Pa pressure.
2. Set Time Averaging to one second.
3. Place a tube, connected to the positive port, in the path of the air stream.
4. Establish a Baseline pressure.
5. Notice that once a Baseline pressure is taken, the measured pressure drops closer to zero,
negating the effects of the wind on the actual measured pressure.
6. Stop the fan.
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