2150EX AV Flow Module - Isco
2150EX AV Flow Module - Isco
2150EX AV Flow Module - Isco
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
<strong>2150EX</strong> Area Velocity <strong>Flow</strong> System<br />
Section 3 Programming<br />
a<br />
h<br />
Level (h) = D a<br />
D<br />
In round pipes it is possible to measure the level without disturbing<br />
the stream surface. This method is preferred. Refer to the diagram<br />
in the margin. First measure the inside diameter of the<br />
pipe (D). Then measure the airspace (a) from the liquid surface to<br />
the peak of the inside diameter. Average this measurement if the<br />
surface is not calm. The level measurement that you enter (h) is<br />
calculated by subtracting the distance above the liquid (d) from<br />
the diameter (D). If difficult channel conditions keep you from<br />
making the measurements as described above, another site<br />
should be considered.<br />
3.3.2 Zero Level Offset <strong>AV</strong> Sensors are sometimes offset in the channel to avoid heavy<br />
concentrations of silt, or to maximize the level resolution over a<br />
specific range. When the <strong>AV</strong> Sensor is offset, an offset distance<br />
must be entered on the Velocity measurement tab in <strong>Flow</strong>link.<br />
Refer to Figure 3-3. Enter a value for the vertical distance the<br />
sensor is installed above the true zero level of the stream. For<br />
example, if the sensor is mounted on the side of the pipe two<br />
inches higher than the true zero level (the bottom center of the<br />
pipe), the Zero Level Offset is two inches. If the sensor is<br />
mounted at the bottom of the channel, enter zero.<br />
Note<br />
Do not confuse the circumferential distance between true zero<br />
and the location of the <strong>AV</strong> Sensor with the vertical distance<br />
(height). If you install the <strong>AV</strong> Sensor at the true zero level of the<br />
pipe or channel, you would enter “0” for the offset (ignoring the<br />
thickness of the mounting ring).<br />
<strong>AV</strong> Sensor<br />
Offset<br />
Distance<br />
Figure 3-3 Zero Level Offset Measurement<br />
True Zero Point<br />
of channel<br />
Circumferential<br />
Distance<br />
3-4