E8500 Instruction & Operations Manual
version 1.010
Page 35 of 45
Calibration procedure
The following page illustrates the sequence of key strokes to carry out a span
calibration of the analyzer. It is assumed that the instrument has been autozeroed and
there have been no error messages.
IMPORTANT: For the NDIR channels, the span calibration must be carried out
within 3 minutes of autozeroing the analyzer.
1. Connect the calibration apparatus and cylinder to the analyzer probe.
2. Press the MEASURE key and observe the target gas reading on the display, as you
open the calibration cylinder valve. (If you are using the bypass flow meter, adjust
the cylinder valve for a bypass flow rate of approximately 400 - 500 cc/min).
Observe the readings of the other gas parameters for evidence of cross
sensitivity and also the oxygen reading for confirmation that there is no
instrument leak, if the balance gas in the cylinder is nitrogen.
3. When the display reading for the desired gas has stabilized, press the CALIB key to
enter the CALIBRATION MENU.
4. Scroll to the sensor that your are calibrating.
5. Enter the span value, printed on the span cylinder. Use the UP, DOWN & OK keys
to change the span value. First set the hundreds digit, then press OK to advance the
cursor to the tens digit, and repeat for the units digit.
6. Pressing OK again will bring up the DATA screen with the confirmation line:
PRESS OK TO SPAN
Press the OK key to begin the calibration. The unit will wait for the amount of time
set as the span time. The display will show the span gas, the span gas value, and
the time remaining.
7. When the calibration is finished, check the sensor accuracy with the calibration span
gas.
You can minimize the span time if you wait for the reading to stabilize before executing
the span calibration. If, instead, you execute the span countdown when you begin to
feed span gas to the analyzer, then the recommended span time is set to 2 minutes for
NDIR calibrations, 4 minutes or more for NO and CO calibrations, and a minimum of 10
minutes for NO
2
and SO
2
calibrations.
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