Hach SIGMA 900, Инструкция по эксплуатации инструмента

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Page 30
Flow Proportional Operation
8544operations.fm
Section 4
Use the following examples to help you determine the value that you need to
enter when programming for sampling based on counts.
Example 1
You want to collect 24 samples over a 24-hour period on a 4–20 mA flow
proportional basis.
Average Flow Rate = 3.5 mgd (average flow rate over the 24-hour period)
Maximum Flow Rate = 10 mgd
a = 1440 minutes
1. Calculate Q .
2. Calculate t .
3. Multiply Q x t.
Therefore, the value entered for
INTV = _ _ _ _ CNTS
is 21.
Example 2
You want to collect 48 samples over a 24-hour period on a 4–20 mA flow
proportional basis.
Average Flow Rate = 1.75 mgd (average flow rate over the 24-hour period)
Maximum Flow Rate = 3 mgd
a = 1440 minutes
1. Calculate Q .
2. Calculate t .
3. Multiply Q x t .
Therefore, the value entered for
INTV = _ _ _ _ CNTS
is 18.
Example 3
You want to collect 96 samples over a 24-hour period on a 4–20 mA flow
proportional basis.
Average Flow Rate = 0.52 mgd (average flow rate over the 24-hour period)
Maximum Flow Rate = 2 mgd
a = 1440 minutes
1. Calculate Q .
Q
Average Flow Rate
Maximum Flow Rate
------------------------------------------------------
3.5 mgd
10 mgd
---------------------
0.35 mgd
= = =
t
a
n
---
1440 min
24 samples
------------------------------ 60 min/sample = = =
0.35 mgd 60 min/sample
×
21
=
Q
Average Flow Rate
Maximum Flow Rate
------------------------------------------------------
1.75 mgd
3 mgd
-------------------------
0.583 mgd
= = =
t
a
n
---
1440 min
48 samples
------------------------------
30 min/sample
= = =
0.583 mgd 30 min/sample
×
17.5
=
Q
Average Flow Rate
Maximum Flow Rate
------------------------------------------------------
0.52 mgd
2.0 mgd
------------------------- 0.26 mgd = = =