User's Guide

Chapter 3. Using Your APS3
3.29
Low Pressure Environment
In low pressure environments below 300 Torr (0.4 atmosphere), the APS device responds in
order to prevent damage, resulting in the following event:
• Pressure below 300 Tor r. The APS device’s fan turns off. The laser remains on and
ParticleSpectrum continues to record and display data. ParticleSpectrum inserts a data
mark into the log file noting that the fan was turned off due to low pressure.
When the pressure returns above 300 Torr, the fan turns on and ParticleSpectrum inserts a data
mark into the log file noting that the fan is functioning.
For operation of the fan to continue running below 300 Torr, select the Device Settings icon.
Under Device Options click Allow fan to run in vacuum button to read ON. This will allow
continued operation of the fan in a vacuum. The Device Status Bar icon for the fan will turn
green.
Note: The Allow fan to run in vacuum is specific to your device hardware. If you power down
the device with the setting still ON, the fan will turn on the next time you power up the device.
If you connect a new APS device that did not have the feature turned on previously, you will
need to go into the Device Options to turn the Allow fan to run in vacuum feature back
ON.
Figure 3.29: Fan Operation in Vacuum
Figure 3.28: Below Pressure Warning and Fan Off
Allow fan to
run in vacuum
Device Status Bar
when fan is running
in a low pressure
environment