6-26
Model 3090/3090AK Engine Exhaust Particle Sizer
TM
Spectrometer
Figure 6-26
Electrometer Offset Values
Noisy Channels
The most common problem with the EEPS spectrometer is that one or more
electrometer channels become dirty or contaminated with material. This
causes the channels to indicate a signal even when filtered air is sampled
by the instrument. In this case, the recommended procedure is to clean the
instrument (see sections above). However, it is also useful to know exactly
how noisy each channel is and which channels are causing a problem. This
can be done using the advanced features of the EEPS software.
Note
: The top two electrometers rings are not actively measured. When
referring to electrometer channel numbers, channel 1 is the third
electrometer ring from the top.
