Cambridge Sensotec Rapidox 1100ZR-H-PFC-E O
2
Analyser Instruction Manual
Version 1.2
7
Last printed 22/07/2015 18:08:00
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7.6
Rapidox Calibration
Full calibration is a simple procedure requiring only two or three gases (one of
which is normally air – 20.95%). The two gas values are user-selectable and can
be changed by using the front keypad (2) or the communications software
described in section 8, and the calibration values can be stored on file for later
use.
Care must be taken to calibrate the analyser so that, whenever possible, the range
of measurement lies between the two calibration point extremes. For example, if
you are working at 10ppm but have calibrated the analyser between 21% and
100% then the analyser will be inaccurate. You would need to calibrate at, say,
1ppm and 21% to be sure of good accuracy. The procedure is as follows:
1)
Bearing in mind the points made above, decide which two (or three) gases
you are going to use for calibration. If you are constantly working at a
particular range of compositions then it would be wise to obtain small
cylinders of calibration gas with analysis certificates. Cambridge Sensotec
can supply these. Press the ENT button on the front panel keypad (2) to
access the menu system. The calibration function is option 1 on the menu
list, which can be scrolled using the UP and DOWN arrows. Press ENT
again to enter the calibration menu. Use the UP and DOWN arrows to
select O
2
HIGH, O
2
MIDDLE or O
2
LOW and press ENT to proceed. The top
line of the display shows the current calibration gas stored and the bottom
line of the display shows the prompts. If the gas value is not what you
require you can edit the value (in ppm scientific notation) using the up and
down and right arrows on the keypad. The cursor flashes underneath the
digit to edit. For example air (20.95%) should be entered as 2.095E+05ppm
(209,500ppm). Note that you cannot go backwards to edit a digit to the left
of the cursor. Instead keep pressing the RIGHT button and the cursor will
wrap around back to the beginning. Alternatively press ESC to start again.
Press ENT when you are ready to proceed.
Scientific
Format
Meaning
Equivalent
ppm
Equivalent
Percent
1.000E+06ppm
1.000 x 1,000,000
1,000,000ppm
100.00%
2.095E+05ppm
2.095 x 100,000
209,500ppm
20.95%
1.000E+05ppm
1.000 x 100,000
100,000ppm
10.00%
1.000E+04ppm
1.000 x 10,000
10,000ppm
1.000%
1.000E+03ppm
1.000 x 1,000
1,000ppm
0.100%
1.000E+02ppm
1.000 x 100
100.0ppm
0.010%
1.000E+01ppm
1.000 x 10
10.00ppm
0.001%
1.000E+00ppm
1.000 x 1
1.000ppm
0.0001%
Table 3: Examples of common scientific format with their equivalent ppm and percent
values
2)
Note that for analysers fitted with an ejector instead of a pump care must be