Hach Ultra MET ONE 227, User Manual

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Operation
4.6 Concentration mode
The Concentration mode in the MET ONE 227 particle counter can be used to take a
quick snapshot of airborne particulate contamination levels, but cannot be used as a
substitute for full sampling. The Concentration mode is appropriate for areas where the
particulate levels are unknown and may exceed the operating limits of the MET ONE 227
particle counter. When the Concentration mode is used, no data records are stored in the
memory buffer.
In the Concentration mode, the MET ONE 227 particle counter begins sampling and
estimates the counts per cubic foot or per liter based on a programmable period of time.
The MET ONE 227 particle counter updates the calculation results on the display at
1-second intervals. The programmable period sets the size of a ‘calculation window’ in
seconds, which is moved each second to incorporate the sample data for the next
second. The sample data for the oldest second of the previous period is then discarded.
The MET ONE 227 particle counter calculates the concentration based on a 3-second
window that moves every one second (refer to
Figure 18 ). The MET ONE 227 particle
counter uses a 10-second period to calculate the concentration based on a 10-second
window that moves every one second.
Figure 17 Completed samples screen
Figure 18 Concentration mode (3-second period)
1 3-second period 3 Recalculation and display update
2 Seconds