Dwyer UFC - Manual (Page 37)

3: Operating Procedures
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3.5 How to Measure Totalized Flows (manually)
The basic measurement indicated on the FLOW READING screen is the instantaneous flow rate, which in some
applications may vary over a period of time. Average flow rates are therefore often required in order to get a
better understanding of an application’s true performance. This is simply achieved by noting the total flow over a
specific period (for example 30-60 minutes) and then calculating the average flow rate over that period of time.
1. Press the Options key to access the FLOW
READING OPTION screen shown.
2. If the Totalizer is indicating Run, select it
and change it to Stall. Press ENTER.
3. Select Reset +Total and press ENTER.
4. Press ENTER on the subsequent screen to
accept the reset.
5. Press ENTER again to return to the FLOW
READING OPTIONS menu.
6. Select Reset –Total and press ENTER.
7. Press ENTER on the subsequent screen to
accept the reset.
8. Press ENTER again to return to the FLOW
READING OPTIONS menu.
9. Note and record the current time.
10. Select Totalizer and change it to Run. Press
ENTER.
Note: the totalizers begin to count up as soon as Totalizer is set to Run.
11. Scroll down and select Exit to return to the
FLOW READING screen which will now indicate
the instantaneous flow together with the
totalized flow.
Note that in some installations the measured
flow can be in either direction. When this is the
case, the upstream flow is shown separately in
the
–Total field.
Calculating the average flow
To calculate the average flow, wait for the allotted monitoring period to expire then divide the indicated total flow
by the time taken. This will give you the average flow in m/s, galls/hour or whatever units you select.
Note that in a bi-directional flow situation you must calculate the difference between the indicated positive and
negative flow totals before carrying out the average flow rate calculation.
How to stop the totalizer temporarily
If you want to stop the totalizer temporarily for operational reasons, set the Totalizer option to Stall in the
FLOW READING OPTIONS screen as described above. This will stop the totalizer operation without affecting its
current values.
FLOW READING OPTION DD-MM-YY HH:MM:SS
Data review
Zero Cutoff (m/s) : 0.010
Set zero flow (m/s) : 0.000
Damping (secs) : 10
Totalizer : Stall
Reset +Total
FLOW READING OPTION DD-MM-YY HH:MM:SS
Zero Cutoff (m/s) : 0.00
Set zero flow (m/s) : 0.00
Damping (secs) : 10
Totalizer : Run
Reset +Total
Reset –Total
FLOW READING DD-MM-YY HH:MM:SS
Qxx.xx%
Signal
gal/min
+Total: 300.0 gallons
–Total: 0.00 gallons
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