Chapter 3
Calibration
Performing Calibration
►
Procedure
Follow the instructions below to calibrate a spectrometer using the HL-2000-CAL:
1. Click on the
Spectrometer
menu and select
Calibrate
, then select the channel to calibrate. A
dialog box opens with the message “Verify lamp was ON for at least 15 minutes for a
REFERENCE scan.”
2. Ensure that nothing is blocking the light path going to your spectrometer. Your setup
(spectrometer, fiber, and sampling optics) used to obtain a reference should be identical to your
setup for measuring your sample. Taking a reference spectrum is required before the software can
calculate absolute irradiance measurements.
3. Click
the
OK
button. Another dialog box opens with the message “Block light path to
spectrometer for a DARK scan.”
4. Completely block the light path to your spectrometer by inserting an opaque object into the
lamp’s filter slot (if possible, do not turn off the light source). Taking a dark spectrum is required
before the software can calculate absolute irradiance measurements.
5. Click
the
OK
button. The spectral response of your system is now calibrated. If you selected
Display calibration info when calculating
in the
Configure Spectrometer
dialog box, you will
now see the results of the calibration procedure. The top left graph represents the linear 15
th
order
polynomial regression. The top right graph represents the dark scan. The bottom graph is the
calibration curve representing the spectral response of the process.
The calibration procedure is saved in a file named
CHO.CAL
for calibrating the master spectrometer
channel,
CH1.CAL
for calibrating the first slave spectrometer channel, and so on.
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