1 using composer monitor software / setup tool – INFICON Composer Gas Concentration Controller User Manual
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Composer Operating Manual
3.2.3.1 Using Composer Monitor Software / Setup Tool
1
From the Setup >> Process Parameters menu option (or its icon on the
Toolbar), set appropriate MFC parameters, gas parameters and total gas
flow.
2
If total flow is to be conserved, the DIP SW#5 on CFGR2 must be set.
3
Connect MFC control cables to the back of the instrument.
4
Evacuate the cell and gas line.
5
Press the BYPASS button in Amp Track mode to start dilution gas flow.
6
Once the flow starts, press the MANUAL button. This will bring up a window
for manually setting gas flows. It should display 0 in the bubbler flow box
and previously chosen total flow in the dilution flow box.
7
Press menu item Actions >> Start Collection (or the play button on the
ribbon bar) to display the graph of measured concentrations. When line
pressure stabilizes, the steady light (or concentration steady sign on the unit
with LCD display) will be illuminated.
8
Press menu item Calibration >> Set User Zero to establish pure carrier
gas frequency.
9
Press the Clear Graph button.
10
Now enter a small value (i.e., 10) in the bubbler flow box. Subtract equal
amount from the dilution flow if total flow is to be conserved.
11
Press the SET FLOW button. This will initiate bubbler flow. Watch the
displayed concentration graph and wait until it levels off. In this manner,
keep adjusting the bubbler flow and the dilution flow until the concentration
reaches a steady value in the neighborhood of your desired operating point.
12
When the steady light (or the concentration steady sign) illuminates, note
the bubbler flow and the displayed mole-%. Compute:
bubbler control output as (5.0 volt)*(bubbler flow)/(bubbler full scale)
Process Gain as (displayed mole-%)/ (bubbler control output).
13
Compute 1/e of the steady state concentration value as
(displayed mole-%)* 0.37.
14
For this step, use the monitor timer on the panel (one on the left). Reset the
timer by double clicking on it. Immediately press the BYPASS button.
Observe the displayed concentration graph. Note the time at which the
concentration starts to fall. This is approximately the dead time. Note the
time at which the displayed mole-% reaches 37% of its original value. This
time is the sum of the dead time and the process time constant. Thus, all
three process parameters are known.