INFICON Cygnus Thin Film Deposition Controller User Manual
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Cygnus Operating Manual
CRYSTAL STABILITY . . . . . . . . . . . 0 to 9 (default = 0)
The Crystal Stability parameter can also be used to effect a crystal fail. In
normal operation, when mass is added to a crystal its frequency of oscillation
will decrease. There are, however, a number of reasons, such as thermal
shock, high stresses in the film, electrical arcing from an electron beam gun, or
frequency instabilities, that may cause a positive frequency shift between
successive measurements. The Crystal Stability function is used to monitor
these positive frequency excursions while the Channel is active. Values range
from 0 to 9. The default value of 0 disables the function. Values 1 through 9
correspond to the maximum positive frequency accumulation permitted. See
Table 3-2
.
Each time there is a positive shift in frequency, the magnitude of the positive
frequency excursion is accumulated. If the cumulative total, or the maximum
single shift, exceeds the limit set by the Crystal Stability value a crystal fail
function is triggered.
CRYSTAL FAIL OPTION . . . . . . . . . 0, 1, 2 (default = 1)
This parameter value determines what action will be taken if there is a crystal
failure for this Channel during control.
0 = Time Power. Entering a value of 0 will cause the Channel to enter the Time
Power state upon a crystal failure.
1 = Idle Ramp. A value of 1 will cause the Channel to enter the Idle Ramp state
upon a crystal failure.
2 = Stop. A value of 2 will cause the Channel to Stop upon a crystal failure.
Table 3-2 Crystal Stability Number and Positive Frequency Accumulation
Crystal Stability
Number
Positive Frequency
Accumulation (Hz)
9
25
8
100 (max single shift of 50)
7
100
6
200 (max single shift of 100)
5
200
4
400
3
500
2
1000
1
5000 (max single shift of 1250)
0
Disabled