Hach Sigma 900 User Manual page 51

8837prg.fm
2. Multiply the flow increment between samples, f, by the pulse frequency
output of the flow meter (i.e. 1 pulse per 100 gallons, 1 pulse per 1,000
gallons, etc.). If the pulse frequency output of the flow meter is not known,
consult the flow meter manufacturer.
Note: The final result is not necessarily a whole number. You must round off the result
to the nearest whole number.
Example 1
You want to collect 35 samples over a 24-hour period. The total expected flow
over this period is 235,000 gallons. The flow meter pulse frequency is
one pulse for every 100 gallons.
1. Determine the flow increment between samples:
Q 235,000 gallons
f
= --- - = ----------------------------------------- -
n 35 samples
2. Multiply the flow increment, f, by the pulse frequency output of the flow
meter.
×
6,714 gallons/sample ----------------------------- -
100 gallons
Therefore, the value for
(67.14 is rounded off to 67.)
Example 2
You want to collect 24 samples over an 8-hour period. The total expected flow
over this 8-hour period is 85,000 gallons. The flow meter pulse frequency
output is one pulse for every 50 gallons.
1. Determine the flow increment between samples:
Q 85,000 gallons
f
= --- - = -------------------------------------- -
n 24 samples
2. Multiply the flow increment, f, by the pulse frequency output of the flow
meter.
×
3,542 gallons/sample
Therefore, the value for
Example 3
You want to collect 48 samples over a 16-hour period. The total expected flow
over this period is 1,750,000 gallons. The flow meter pulse frequency output
is one pulse for every 1,000 gallons.
1. Determine the flow increment between samples:
Q 1,750,000 gallons
f = --- - = ---------------------------------------------- -
n 48 samples
2. Multiply the flow increment, f, by the pulse frequency output of the flow
meter.
×
36,458 gallons/sample
Therefore, the value for
6,714 gallons/sample
=
1 pulse
67.14 pulse/sample
=
is 67.
INTV = _ _ _ _ CNTS
3,542 gallons/sample
=
1 pulse
-------------------------- - 70.84 pulse/sample
=
50 gallons
is 71.
INTV = _ _ _ _ CNTS
= 36,458 gallons/sample
1 pulse
---------------------------------- -
= 36.458 pulses/sample
1,000 gallons
is 36.
INTV = _ _ _ _ CNTS
Flow Proportional Operation
Section 5
Page 51