MKS 649A - Figure 11: Controller Response with Increased P Term; Figure 12: Controller Response with Increased I Term

Tuning the 649 Pressure Controller Cha
p
ter Three: Overview
28
Controller Response with Increased P Term
Increasing the P term to 1 while holding the I term at 0 yields:
P = 1
I = 0
Settlin
g
Time
Settlin
g
Time
Set Point
Si
g
nal
4
2
6
8
Pressure, (Torr)
Time
Figure 11: Controller Response with Increased P Term
The controller responds much faster, however some overshoot occurs.
Controller Response with Increased I Term
Reducing the P term to 0 and increasing the I term to 5 yields:
P = 0
I = 5
Settlin
g
Time Settlin
g
Time
Set Point
Si
g
nal
4
2
6
8
Pressure, (Torr)
Time
Figure 12: Controller Response with Increased I Term
The response of the controller is quick, yet no overshoot occurs. This combination of P term and
I term yields the best control for our example system.