INFICON IC6 Thin Film Deposition Controller - Manual (Page 112)

5 - 4
PN
07
4-
50
5-
P1
F
IC6 Operating Manual
CONTROL LOOP . . . . . . . . . . . . . . NonPID (0), PI (1), PID (2)
The bracketed value is used for changing the setting via the remote
communications commands. This parameter establishes the control loop
algorithms pertaining to either a slow responding source or a fast responding
source. The default value is NonPID (0).
NonPID is best for fast and medium speed responding systems with high
noise levels (for example, an electron beam gun with or without a liner, having
a large sweep amplitude of low frequency, 10 Hz or less).
PI is best for fast, medium, or slow systems with medium noise levels (for
example, an electron beam gun with medium sweep amplitude frequency, 20
to 100 Hz; also, sputtering and resistive sources).
PID is best for fast, medium or slow systems with low noise levels (for
example, an electron beam gun with sweep off or at a high frequency, 100+ Hz,
and sputtering and resistive sources).
PROCESS GAIN . . . . . . . . . . . . . . . 0.010 to 999.990 Å/s/% pwr
This parameter determines the change in % Power for a given rate deviation
(dRate/dPower). The larger the Process Gain value, the smaller the change in
power for a given rate error. Process Gain is calculated by dividing the change
in rate caused by the corresponding change in power. The default value is
10.00.
TIME CONSTANT . . . . . . . . . . . . . . 0.010 to 9999.99 s
This is the evaporation source’s time constant. This value is defined as the time
difference between the actual start of a change in rate and the time at which
63% of the rate step is achieved. This value may be measured according to the
above criterion or it may be determined empirically. The default value is 1. This
parameter is disabled if the CONTROL LOOP option parameter is set to 0
(NonPID).
Figure 5-4 Time constant
R A T E IN C R E A S E
6 3 % P O IN T
T IM E C O N S T A N T
T IM E
R
A
T
E
P
O
W
E
R
R A T E IN C R E A S E
6 3 % P O IN T
T IM E C O N S T A N T
T IM E
R
A
T
E
P
O
W
E
R
R a te
P o w e r