Select The Sample Distribution-Multiple Bottles - Hach AS950 Operation Manual

CTVV sampling
Constant Time Variable Volume (CTVV) sampling collects samples at a fixed time interval. But, the
actual volume of each sample is based on the:
• Entered flow range for the site
• Entered sample volume range
• Actual measured flow at the time of sampling
The sample volume collected is based on the measured flow of the stream when the sample is
collected. The sample volume increases linearly as the flow rate increases (or decreases) between
the low flow rate and high flow rate entered.
When CTVV is used for sampling:
• The liquid detector is always enabled.
• The first sample is collected after the first time interval set in the Pacing setting.
• The flow source can be any flow source with the exception of AUX-Pulse.
• Samples are only collected when the flow is between the entered low flow value and high flow
value.
The sampler calculates the sample volume to collect based on the user settings and the actual
measured flow. For example, the actual measured flow is 200 gph and the entered values are:
• Low Flow: 150 gph
• High Flow: 300 gph
• Low Flow Sample: 1500 mL (sample volume for low flow)
• High Flow Sample: 3000 mL (sample volume for high flow)
Calculation 1: Sample volume per unit of flow
(High Flow Sample – Low Flow Sample) ÷ (High Flow – Low Flow) = 1500 mL ÷ 150 gph =
10 mL/gph
Calculation 2: Sample volume
Measured flow at time of sampling × Sample volume per unit of flow = 200 gph x 10 mL/gph =
2000 mL of sample collected
Select the sample distribution—multiple bottles
Select the sample distribution among the bottles.
1. Push MENU.
2. Go to Programming>Sample Programming>Distribution.
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