Hach-Lange Sigma SD900 Portable - Manual (Page 57)

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Advanced sampling
the total length of the stormwater collection period. First flush
samples are usually collected within 30 minutes of a storm.
Note: The number of intervals is determined by the number of bottles
and the distribution mode.
9. Enter the volume of each first flush sample.
10. Select ENABLE to set a time limit for stormwater collection.
Enter the program time limit. The program will stop when this
time limit is reached.
Select DISABLE to allow the program to run until complete
without a time limit.
NPDES requirements typically request monitoring for the first
three hours of a storm. If the flow volume is lower than
expected, flow-weighted sampling could continue for some time
as flow rates drop and sample intervals become longer.
5.3.6 Set variable intervals
Variable time or flow intervals can be set for sample cycles.
Intervals will be in hours and minutes if the sample pacing mode is
time based. Intervals will be in counts if the sample pacing mode is
flow based.
Procedure:
1. Select PROGRAM SETUP > MODIFY SELECTED > ADV SAMPLING
from the main menu.
2. Select VARIABLE INTVL > ENABLE .
3. Enter the time (or count) interval between each sample cycle.
Up to 99 intervals can be entered.