4 auto tune — optimizing the control loop, 5 rate watcher – INFICON IC6 Thin Film Deposition Controller User Manual
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IC6 Operating Manual
If the IC6 loses the ability to measure the fundamental frequency and all
available crystals in a multi-position sensor head are flagged as failed, and a
backup sensor is not available, the Crystal Fail message is displayed and the
Xtal Fail logic state becomes true.
Unable to Auto-Z
An “unable to Auto-Z” condition occurs whenever:
The anharmonic frequency cannot be measured.
The fundamental and anharmonic frequencies of the monitor crystal have
not been continuously measured from the uncoated to the coated state.
3.6.4 Auto Tune — Optimizing the Control Loop
Control loop parameters can often be calculated automatically by the IC6. This is
done by using the AutoTune feature. See
section 12.5, AutoTuning, on page 12-5
3.6.5 Rate Watcher
The IC6 includes a sample and hold function which enables periodic sampling of
the deposition rate by opening and closing the sensor shutter. If you are controlling
inherently stable deposition sources, this function is useful in maximizing crystal
life. When RateWatcher is enabled, during deposit, rate control will be established.
The sensor shutter will close for a designated amount of time. The shutter will once
again be opened to validate and adjust the power level. This procedure is repeated
throughout the deposition. Two Material/Deposit parameters—RateWatch Time
and RateWatch Accuracy—control this function. See
.