Ametek Land 4200, Руководство пользователя

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User Guide Model 4200 Dust & Opacity Monitor
10.1.2 Span Check
Remove the reflector holder and turn it into the reverse plane so that when
placed in the same filter holder position (1) as before. The blank, non reflective
surface is now facing towards the display end of the instrument. After a short
period of time the display value should read 100. This represents 100% opacity
any deviation from this value signifies the span drift.
If either drift is unacceptable, outside the instrument specification (< 2%), or
local authority requirements, then a re-calibration is required. See the following
re-calibration procedure.
10.2 Linearity Filters
Two (optional) filters are available that can be obtained from Land Instruments
International. They represent a nominal 8% and 20% opacity. These filters can
be introduced into a calibration audit procedure to confirm the linearity of the
system.
1) On completion of the calibration audit check for zero and 100% span
continue with the following steps:
2) Place the zero reflector holder with the reflecting surface facing the display
end of the transmissometer in the position nearest the stack.
3) Place the 20% filter in the other vacant filter holder position.
4) Allow the display reading to settle and the display should indicate 20%
(opacity).
5) Follow steps 3 and 4 this time using the 8% filter. The display should read
8% opacity.
Note
On older instruments, the display shows the double-pass opacity value
Instruments with Software V1.10 and later, the display shows the single
pass opacity, which matches the calibrated opacity value for the filter.
10.3 Method 1 - Clear Path Calibration (Opacity)
If the calibration audit has shown that the calibration of the Model 4200 is
outside the acceptable range first of all ensure that all optical surfaces are clean
and the optical path is not obstructed. If re- calibration is needed it must be
carried out by a Land Service Engineer or other competent person.
Re-calibration must only be carried out under clear stack conditions with the
process off or in laboratory conditions with the transmissometer set to the
correct flange-to-flange path length. If clear stack conditions are not possible
then use Method 2 (This method does not calibrate out any changes with the
retro-reflector - i.e. dirty reflector).