Cambridge Sensotec Rapidox 1100E Oxygen Analyser Instruction Manual
Version 3.8
6
Last printed 29/08/2012 16:01:00
password is entered then the full menu will be accessible. You can make as many
changes as you want to the options and only press ESC once you have finished.
Pressing ESC takes you out of the password protected area and you will have to re-
enter the password to go back in again.
If the password has been forgotten please contact Cambridge Sensotec who will
advise you on how to recover it.
6.6
Rapidox Calibration
Once the unit is stable it may be necessary to calibrate the sensor. If a new sensor
is fitted this will also require recalibration. Full calibration is a simple procedure
requiring only two gases (one of which is normally air – 20.95%). For best
accuracy the second gas should ideally be 0% oxygen (e.g., pure N
2
). The two gas
values are user-selectable and can be changed by using the front keypad (2) or the
communications software described in section 7, 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 points. For example, if you are
working at 1% but have calibrated the analyser between 21% and 100% then the
analyser may be inaccurate at 1%. You should instead calibrate using pure
nitrogen (0%) and 21% to be sure of good accuracy. The procedure is as follows:
1)
Bearing in mind the points made above, decide which two 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. Using the UP and DOWN arrow buttons scroll to menu
option 1 “Calibrate” and press ENT again to enter the calibration menu.
The analyser will ask you if a new sensor has been fitted with the prompt
“NEW SENSOR?” The default answer is NO unless you have just replaced
the sensor and in this case use the UP or DOWN key to change to YES.
Selecting YES allows the machine to store the unique profile of the new
sensor so it can advise you when the sensor is ready to be replaced. Use the
UP and DOWN arrows to select “O
2
High” 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 20.95% should be
entered as 2.095E+05ppm. 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.
2)
The sensor needs to be exposed to the first calibration gas (e.g., air) or from
Содержание SENSOTEC Rapidox 1100E
Страница 46: ......
