Linearity Test; Figure 141 Pwd Maintenance Interface - Vaisala LT31 User Manual

Chapter 6 ______________________________________________________________ Maintenance

Linearity Test

VAISALA ______________________________________________________________________ 245
maintenance cable (which is delivered together with the LT31). PWD
maintenance interface is shown in Figure 141 below.
Apart from getting access to the full PWD command set this interface
provides a convenient means for updating the PWD software.
Figure 141 PWD Maintenance Interface
For test purposes, it might be necessary or helpful to 'create' visibility
situations in order to evaluate or verify the measurement performance of
the LT31 system. 'Creation' of visibility, namely reduced transmittance,
can be done by applying optical filters to the optical path of the
transmissometer.
The LT31 system provides the Linearity Test menu, thus there is no
need for manual calculations.
In combination with the LT31 Optical Filter Set (LTOF111), the linearity
test is an easy to handle procedure. LTOF111 consists of a filter holder
and several calibrated optical filters. Before applying any optical filter to
the optical path, the filter holder has to be mounted to the Support Unit
Receiver (LTS211). Figure 142 on page 246 shows the filter holder
mounted.
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