INFICON IC/5 Thin Film Deposition Controller - Manual (Page 224)

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Statement 10 is also tied to Statement 7 by its dependency on Timer 3. This is done
to ensure that Statement 10 cannot be true unless Statement 7 is true. Since the
status of the Crossover pressure in Statement 10 is the same as in Statement 8 this
is needed to differentiate between the two conditions (i.e. how we arrive at the
cross overpressure, via Statement 7 or Statement 8). Timer 9 is used as a delay
between closing the roughing valve and opening the foreline valve in Statement 11.
Figure 10-16 Statement 11
A branch in the logic processing occurs at Statements 7 and 8. Which progression
the logic processing takes is dependent on the condition of the Crossover
pressure. If the chamber pressure is at or below the Crossover pressure the logic
progression will go from Statement 6 to Statement 8 to Statement 12. If the
chamber pressure is above the cross over pressure the logic progression will go
from Statement 6 to Statement 7 to Statements 9 though 11. Statement 11
completes the branch, opening the foreline valve and setting a 20 second timer
which acts as a delay prior to opening the high vacuum valve. Timers 5 and 6 serve
the same purpose. Which timer is set is dependent on the logic branch taken.
Timers 3 and 9 are canceled so that Statement I I can be true only once each time
Statements 7 and 10 are true.
Figure 10-17 Statement 12
Statement 12 monitors the delay timers 5 or 6 and opens the High Vacuum Valve
when the delay time is expired. Timer 7 is set in order to delay turning on the Ion
Gauge after opening the High Vacuum Valve. Timers 5 and 6 are immediately
canceled so that Statement 12 can be true only once during each process cycle.
Figure 10-18 Statement 13
Statement 13 turns on the Ion Gauge when the 20 second time delay defined by
Timer 7 expires.