INFICON IQM-233 Thin Film Deposition Controller PCI-Express Card Operating Manual - Manual (Page 96)

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IQM-233 Operating Manual
10 Adjust PID Values according to control response
 Set Source Control to Auto to activate PID control and observe the power.
 The power should rise from 0% and stabilize near PWR
DR.
 If there is more than 10% overshoot in power or if the curve
appears under damped, lower the P value. If the time to reach
PWR
DR
is very slow (over damped), increase the P value. See
Figure 6-3 .
 A lower I value will increase response for over damped sources. A
higher value may reduce ringing and rate deviations seen with
under damped sources. See
Figure 6-3
 The D value should not need much adjustment, but if under
damped behavior is observed, increase the D value. If it appears
over damped, decrease the D value. See
Figure 6-4 .
 Continue to adjust P and I values, alternating between 0% power in Manual
mode and Auto mode until the steady-state response is smooth and the
step response is controlled.
 If finished, slowly decrease power to 0%, and then press Stop.
NOTE: Preconditioning will minimize step changes.
NOTE: E-beam systems may require additional steps to limit the control loop
response during arcing. First, be sure the Max Power parameter in the
Source Setup window is set to limit the output to a reasonable value for
the material and rate. The Slew setting can further limit aggressive
power changes, see
section 3.3.3.1.4 on page 3-14 . At rates below 10
Å/s, a Slew of 1 - 2% is common. Increasing the Filter Readings
parameter will limit the PID response to occasional large noise spikes,
such as those from arcing.