Dwyer Series PUB - Manual (Page 27)

3: Operating Procedures
23
3.6 Performing Monitoring Functions
3.6.1 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 to 60 minutes) and then calculating the average flow rate over that period of time.
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 take the difference between the indicated positive and
negative flow totals before carrying out the average flow rate calculation.
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 then press the ENTER key.
3. Select Reset +Total and press the ENTER
key.
4. Press the ENTER key on the subsequent screen
to accept the reset.
5. Press the ENTER key again to return to the FLOW
READING OPTIONS menu.
FLOW READING OPTION DD-MM-YY HH:MM:SS
Data review
Zero Cutoff (m/s) : 0.00
Set zero flow (m/s) : 0.00
Damping (secs) : 10
Totalizer : Stall
Reset +Total
6. Select Reset –Total and press the ENTER
key.
7. Press the ENTER key on the subsequent screen
to accept the reset.
8. Press the ENTER key again to return to the FLOW
READING OPTIONS menu.
9. Note and record the current time.
10. Select Totalizer and change it to Run then
press the ENTER key.
Note: the totalizers begin to count up as soon as
Totalizer is put to Run.
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
11. Scroll down and select Exit then press the
ENTER key to return to the FLOW READING
screen which will now indicate the instantaneous
flow together with the totalized flow.
Note that in some installation the measured flow
can be in either direction. When this is the case,
the upstream flow is shown separately in the
–
Total field.
FLOW READING DD-MM-YY HH:MM:SS
Qxx.xx%
Signal
gal/min
+Total: 300.0 gal
–Total: 0.00 gal
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