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Cygnus 2 Operating Manual
Matl indicates the Z-Ratio being used for thickness calculation is the value
found in the Material parameter Z-Ratio.
Auto indicates Cygnus 2 Auto-Z feature is used for thickness calculations.
Auto-Z continually calculates the Z-Ratio for the "as deposited" film. If Cygnus
2 suddenly lost the ability to calculate Auto-Z, Auto would change to either Matl
or Sens. Matl has the same meaning as described above, Sens indicates the
last calculated Auto-Z value (prior to failure) is used for thickness calculations
for this Sensor.
Cygnus 2 determines to use Matl or Sens depending on the frequency of the
fundamental resonance. If the fundamental frequency closely matches the last
valid fundamental frequency prior to Auto-Z failure, Cygnus 2 will use the Sens
value. Otherwise Cygnus 2 will use the Matl value.
Act(ivity)
Activity is a measure of the Sensor circuit health or ability to conduct current.
The values range from a maximum of 800 (healthiest) to a minimum of 0 (least
healthy).
The Activity value is useful for predicting when a crystal needs to be replaced.
If a crystal is about to fail, its series resistance will increase, allowing less
current to flow through the crystal and hence the Activity value will decrease.
The closer the Activity value is to zero, the more imminent a crystal failure.
Activity also can be used to gauge the health of the sensor head electrical
contacts. For example, if a new monitor crystal is placed into the sensor head
and has a crystal life of near 0%, but the Activity value for this crystal is lower
than 550, this indicates the sensor head or in-vacuum cable is in need of repair.
Frequency
This field is subdivided into two categories: Fundamental and
Anharmonic.The Fundamental frequency will be shown for all working
Sensors. If Auto-Z is in effect for the Sensor, the Anharmonic frequency will
also be shown. Frequency value will be displayed.
3.3.3.4.1 TEST XIU
To test any XIU (Crystal Interface Unit), move the cursor onto the respective
Sensor number. Pressing F1 then initiates the XIU self test. The XIU self test
determines whether the crystal interface unit (XIU) and measurement card pair
is operating properly. "XIU Test Passed" message will appear to indicate this.
"XIU Test Failed" message will appear when there is a defect in the XIU itself,
the XIU interface cable or the measurement card.
For the XIU self test to work properly, the XIU must have the six inch BNC cable
(IPN 755-257-G6) attached and must be disconnected from the sensor
feedthrough.
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