Table of Contents
Advertisement
RUSKA 7750i
Users Manual
Optimizing Control
The performance of the controller may be optimized for certain environments or
performance criteria by adjusting the values available in the Control screen. The Control
screen is available from the Main Menu by pressing Menu [F6], Test [F5], Control [F6].
The Control screen is shown below.
Be sure the Control Band parameter is set to zero (Chapter 4, Menu; Menu | Setup;
Menu | Setup — Limits; Auto Vent).
If the controller does not control optimally, it would be recommended to first assure that
the system is free of leaks and is operating within the external volume specifications
(see Appendix A). You should verify that the instrument is fitted with the proper sized
pressure lines to minimize flow restrictions (see Chapter 3, Pneumatic Connections).
Verify that the control band is set as intended (see Chapter 4, Auto Vent). For active
control, when testing the controller the Control Band Off and Control Band On values
should be set to zero. Finally verify that the control is set to Normal to minimum
overshoot (see Chapter 4, Menu; Menu ⎢Setup; Control Band). If the system continues to
control improperly, you can perform the Auto-tune. You will need to press the MODE
key to select either the Ps or the Qc channel.
There are two options available to the operator.
Full — This fully characterizes the control function of the RUSKA 7750i. It
automatically adjust the control valve biases and aligns the inner loop high control
pressure sensor to the high accuracy quartz sensor. This should be performed any time
major components are replaced in the controller such as the control valves or the
high-speed inner loop control sensor. Additionally, if the controller is not functioning
properly, a full Auto-tune can be performed to optimize the control.
Calibrate — This automatically aligns the inner loop high control pressure sensor to the
high accuracy quartz sensor. If in the Normal control mode (as opposed to the fast control
mode), the controller overshoots the commanded pressure valve, this could be an
indication that the inner loop control sensor needs to be realigned with the high accuracy
quarts sensor. This is achieved by running the Calibrate Auto-Tune function.
6-12
Figure 6-9. Menu | Menu | Test | Control
Note
gme36.bmp
Advertisement
Table of Contents
