Determine the full scale value with the estimate of the maximum cumulative particle counts at the
sensitivity of the instrument, >2 μm. When the value is determined, calculate the estimated full scale
value for other channels with the applicable divisor. Refer to
Table 4
.
4
Table 3 Sample size reference table (flow = 100 mL/min)
Count Period (seconds)
Sample Size (mL)
Count Period (seconds)
Sample Size (mL)
6
10
24
40
12
20
30
50
15
25
48
80
18
30
60
100
Table 4 Divisors for full scale value determination (> 2µm)
Channel
Divisor
Channel
Divisor
Channel
Divisor
>3µ
3.4
>7µ
43
>11µ
166
>4µ
8
>8µ
64
>12µ
216
>5µ
15.6
>9µ
90
>14µ
343
>6µ
27
>10µ
125
>15µ
422
Complete a SCADA calculation
When the values are specified after each analog output for the lower limit, the upper limit and the full
scale, the SCADA programmer enters the values for: The channel range, the upper size limit and the
full scale value. The lower limit (4 mA) will always be 0 counts. In all cases, the lower limit signal
(4 mA) will be 0 (zero) particles, the upper limit signal (20 mA) will be equal to the full scale value.
The full scale value must then be divided by the sample volume (mL sample).
For example: If the sample flow rate is 100 mL/min, a count period of 30 seconds, the sample volume
result is 50 mL. The maximum expected particle count is 1000 particles/mL. Then, the FS value =
1000 particles/mL x 50 mL = 50,000 CH0 set to cumulative particle counts > 2 μm. Refer to
Table 5
.
Table 5 SCADA calculation
CH
Lower
Upper
Full scale
Label at SCADA
4 mA =
20 mA =
Divide by
5
0
2
0
5000
>2 μm
0
5000
50
1
5
0
3200
6
>5 μm
0
3200
50
2
7
0
1166
2
>7 μm
0
1166
50
3
10
0
400
2
>10 μm
0
400
50
Maintenance
W A R N I N G
Multiple hazards. Only qualified personnel must conduct the tasks described in this section of the
document.
4
To make an estimate for the divisors of the values that are not shown in the table, use the
formula that follows: Divisor = (Size/2)
3
. For example, the divisor for >18 μm is (18/2)
3
= 729
5
Divide by the value that value equals the mL sample used to calculate the full scale value.
6
Divisor applied from
Table 4
on page 20
20
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