User's Guide

Chapter 3. Using Your APS3
3.19
Changing the Horizontal Scale
You can set the horizontal scale for the particle measurement graph. The scale will list time in
seconds, or can list Absolute Time Labels.
The horizontal scale setting affects only the display of the particle measurements. The APS
device always sends measurements once per second to ParticleSpectrum, and log files always
record measurements at increments of one second.
To change the horizontal scale to list Absolute Time Labels:
• In the Graph Options, under Absolute Time Labels, select the button to read ON.
The new setting takes effect immediately.
• The graph window will adjust to the units that have been selected. The horizontal
scale bar can be adjusted to accommodate the larger values, and the Zoom out to
extents button in the upper right of the graph window will also adjust to the new
values if you’ve already recorded data.
Figure 3.19: Horizontal Scale
Changing the Averaging Interval
The values displayed in the numerical readouts are moving averages of the particle
measurements. ParticleSpectrum averages the raw data over an interval that you specify.
ParticleSpectrum displays both the raw data and the averaged data in the graph.
The averaging interval you specify affects only the display of the particle measurements. The
APS wafer provides the following:
• Measurements are always sent once per second to ParticleSpectrum and log files
always record the raw measurements at increments of one second.
• The APS airflow is always 0.1 cubic feet per minute.
Horizontal scale bar
Absolute Time
Labels
Absolute Time Labels
Time Labels