Thermo 42i - Calibration

Calibration
Calibration
4-2 Model 42i Low Source Instruction Manual Thermo Electron Corporation
3. Be sure the instrument is in the auto mode, that is, NO, NO
2
, and NO
x
measurements are being displayed on the front panel display. If the
instrument is not in auto mode:
a. Press to display the Main Menu, then choose Instrument
Controls > Auto/Manual Mode.
b. Select NO/NO
x
, and press .
c. Press to return to the Run screen.
4. Select the RANGE soft key if available or locate this function in the
menu to display the Range screen.
5. Select NO range, and push the AVG soft key to display the Averaging
Time screen. It is recommended that a higher averaging time be used for
best results. For more information about the ranges or averaging time,
see the “Operation” chapter.
Note The averaging time should be less than the zero duration and less than
the span duration. 
6. Set the calibration pressure to the current reactor pressure.
a. Push , choose > Calibration Factors > Cal Pressure.
b. Use to increment/decrement the value to match the
current reactor pressure, and press to save the new calibration
pressure value.
7. Verify that any filters used during normal monitoring are also used
during calibration.
8. Connect the analog/digital outputs to a strip chart recorder(s) or PC(s).
Calibration Note that with a Model 42i Low Source equipped with internal zero/span
and sample valves, the ZERO and SPAN ports should give identical
responses to the sample port when test gases are introduced. The user should
calibrate the Model 42i Low Source using the sample port to introduce the
zero and span gas sources. After calibration, the zero and span sources
should be plumbed to the appropriate ports on the rear panel of the Model