User's Guide

Chapter 3. Using Your APS3
3.27
Monitoring the Pressure, Laser, Fan
In addition to connection, battery, and temperature, ParticleSpectrum includes indicators for the
status of the atmospheric pressure, the laser, and the fan:
• Fan. The APS device uses a fan to flow gases in the local atmosphere through the
particle detector. When the fan is operating, this indicator is green; otherwise the
indicator is grey. If the fan
• Pressure. For the fan to work, local atmosphere must be at a minimum pressure of
0.4 atmosphere. When the pressure is high enough for good readings, the Pressure
indicator is green; otherwise the indicator is red. If the APS device detects pressure
dropping below 0.4 atmosphere, the fan and laser will automatically turn off to
prevent damage.
• Laser. The APS particle detector works by scattering laser light off of the particles.
The Laser indicator is green when the laser is operating; otherwise the indicator is grey.
Figure 3.27: Pressure, Laser, and Fan Status
Device Status bar when not
measuring
Device Status bar when
measuring