MNL000423.doc
Revision 01
09/18/2018
© Versum Materials, Inc. as of the revision and date shown. All rights reserved.
Confidential and Proprietary Data
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The processor monitors all 8 levels once a second and updates the display. To prevent
undesirable switching at any level while bubbling, the processor will not update the
display or change relay outputs until the transition remains constant for more than 5
seconds. This is known as a software discriminator function block.
The Low Chem Level alarm will be activated when the liquid level is lower than or
equal to the assigned alarm level set for the “Low Chem Level”. See Parameters &
Limits menu for illustration of setting.
In this design, there are four additional level setpoints that can be assigned to
dedicated relay outputs. Even though the relays can be configured to activate at the
same level as the Low Chem Level alarm, these are independent of the Low Chem
Level alarm output. The Low Chem Level alarm output is determined by the % level
set in the configuration screen “Low Chem Level”. There is a separate configuration
screen for the four other levels.
Once a Low Chem Level alarm is activated the he bubbler should be replaced as
soon as possible to prevent the bubbler from going empty.
NOTE:
Attaching labels on the bubbler in the level sense line of sight will render this
feature useless. Figure 5.4C illustrates clearance locations for line-of-sight
level sense PCA’s.
Due to manufacturing tolerances of quartz bubbler, each bubbler will have variations in
diameter and curvature especially near the top and bottom. The quartz bubbler has an
approximate diameter of 6 inches. The bubbler can move approximately 0.125” within
the Source Cup’s diameter due to diameter tolerances of the bubblers.
This will have an effect on the actual percent of full that each discrete level sense
position will represent. The percent of full values displayed on the front panel were
derived from the mean average of a sample of bubblers measured at the factory.
The displayed values are height percentages. That is, the values are the percentage of
the height of a full (1200cc) bubbler. Due to the lack of repeatability, the values are
approximations and should be used for reference only. The percent (%) readout based
on bubbler chemical levels are shown on Table 5.1 and illustrated in figure 5.4B.
