INFICON Cygnus Thin Film Deposition Controller - Manual (Page 61)

2 - 25
IP
N 07
4-
37
9-
P1
K
Cygnus Operating Manual
A crystal switch will NOT automatically occur:
 During a state of STOP or READY.
 During deposition, if the secondary crystal of a CrystalTwo sensor fails, or the
last good crystal of a Rotary, CrystalSix, or Crystal12 fails. (In either case a
TIME-POWER, IDLE-RAMP or STOP will occur, depending on the crystal fail
option chosen.)
A crystal switch can be manually executed via the front panel, hand-held controller,
remote communications, or logic statements when the system is configured for
CrystalTwo, CrystalSix, Crystal12 or Rotary sensors.
NOTE: When crystal switching with the hand-held controller, Cygnus must be on
a screen with a channel selected.
2.7.2 Rotary Sensor Crystal Switching
Selecting type 7, Rotary, as the sensor type enables sequential crystal switching
only. Upon a crystal switch the Crystal Switch Output will first close for one second
and then open (i.e., one pulse to move one position). Cygnus will not keep track of
which position the Rotary Sensor is on nor will it keep track of which crystals are
good and which are failed. After the one second pulse, Cygnus measurement
system software will attempt to find the resonant frequency for the crystal in this
position. If the Cygnus does not find a good resonant frequency for this crystal it
will again pulse the Crystal Switch Output for one second and attempt to find a
resonant frequency at this position. There will be a maximum of five attempts to find
a good resonant frequency (i.e., a maximum of five pulses of the Crystal Switch
Output). If a good resonant frequency is not found after five attempts, the Cygnus
will then enter the Time Power, Idle-Ramp or STOP state depending on the Crystal
Fail Option value chosen in the Channel Process Display.
There is to be a maximum of five attempts to find a good resonant frequency.
However, if the Cygnus detects a crystal fail and automatically initiates a crystal
switch it will recognize there has been an automatic crystal switch. The Cygnus will
keep track of the number of times an automatic crystal switch has been done.
Therefore if there have been five automatic crystal switches and then the sixth
crystal fails, Cygnus will go directly to either Time Power, Idle-Ramp, or STOP as
appropriate without any additional pulses.
After a ’Start’ command, all crystals are assumed to be good.