Plasma Gas Analyzer
29 02001001A_9
On power up the flow control valve (ref. figure 3) is cold and it may take up to two minutes for the
gas to flow through. Once the valve is warm the flow will stabilize.
If the flow is set to 0 cc for a while the valve will cool down again and require further time to
stabilize when flow is re-initiated.
CAUTION
Never leave the flow set point higher than zero cc if gas is not available, as there is a
risk of damaging the valve, and flow module replacement will be necessary. For this
reason make sure that gas is available before powering up the analyzer.
Purge the analyzer for a minimum of 10 hours with good quality argon.
When the system is powered up, the flow set point has a default value of 75 cc; it normally does
not require further setting, except for faster purging. In this case, increase the flow to 190 cc to
purge the analyzer for a minimum of 2 hours.
After the purge time is elapsed, you may adjust down the by-pass rotameter to an acceptable
flow, depending on the speed of response required and the distance between the analyzer and
the source of gas to be analyzed. The analyzer flow set point may be returned to 75 cc/m.
You are now ready to calibrate the analyzer, refer to section 0.
Once the calibration is done, the analyzer is now functional; it will take a few days for the
analyzer to stabilize itself. For this reason, it may be necessary to recalibrate.
5.2 Routine and operational verification
From time to time, it is a good idea to go in to the "DIAGNOSTIC MENU", check cell counts with
a reference gas and record this value for comparison with a later value. This gives an indication
of the degree of cell offset.
Also, check the flow count stability. Too much variation is an indication of line clogging.
The frequency of calibration is normally once a week.
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