E C O P H Y S I C S Calibration
CLD 780 TR / July 2000 86
6.2.3 Multi point calibration (checking)
For a complete calibration the linearity of the analyzer must be checked
(according to EPA at least five points equally spread over the range have
to be checked).
The multi-point calibration is best performed with a recorder connected to
the analyzer.
1. Selection of measurement mode:
– Press ”MENU“ key
– Select ”Mode“ and confirm the selection with ”YES“
– Select the NO measurement mode
– Confirm with ”YES“.
– Return with ”MEAS“.
2. Selection of the measurement range
–push ”RANGE“
– select the desired range and confirm with ”YES“
– return with ”MEAS“
3. Perform a single-point calibration according to 6.2.2. Return to measu-
ring mode with ”MEAS“.
4. Adjust the calibrator to give the required concentration (dilution ratio),
and note this value. It is recommended to use concentrations of 0, 25,
50, 75 and 100% of the instrument full scale.
5. Wait until signal is stable, then note the value displayed. Repeat for e-
very point.
6. Draw the calibration curve (measured values vs calibrator values) or
calculate the deviation.
7. If required, and if a PLC 762 is being used in combination with the a-
nalyzer, then the NO.c channel may also be checked for linearity. In
this case, in Step 1 above choose NO.c in the submenu ”Mode“
instead of NO. The repeat steps 2 to 6.
Caution: The deviation of the measured values from the calibration
gas values should not exceed the tolerances of the analyzer and cali-
bration instrument combined!
To Next Page
Loading...