34 ER3000 User Manual
6.2 Tune the Typical Application
This tuning procedure utilizes the Windows Tuning program ER3000 (CVI) and is taken
from the ER3000 (CVI) On Line Help. It applies to the above typical application using
external feedback.
To begin, it should be realized that the tuning of PID controllers is learned with
experience. However, the following basic concepts should allow the inexperienced user
to tune their loops sufficiently for use on a majority of applications.
There are some features of the ER3000 that are unique when compared to other PID
controllers that allow the system to be optimized. In particular, the use of four different
modes of operation, the setting of minimum values for inlet and exhaust valves
(deadband adjust) and the setting of maximum and minimum values for the integral sum
allow for greater flexibility in the ER3000 system.
To begin, three windows should be opened:
• Tuning (Advanced!) --- Select ‘Gains’ in Format Menu
• Signal Generator
• Plot
Each system has unique requirements. Since tuning will always be a compromise
between various tradeoffs, it is necessary to decide what are the most important
parameters for the given application. Typical goals include the following:
• Maximize speed of response.
• Minimize peak overshoot.
• Minimize offset.
• Minimize settling time.
In addition, the region of operation will affect how the unit is tuned. This application
will be operating primarily in the 0 to 2500 psi region. Thus tuning should be performed
over this entire range. However, the final setup should be tested in intermediate pressure
ranges as well, to verify maximum performance throughout the system’s range.
In the Tuning Window, make sure the Control Mode is set to External Feedback and the
Sensor Range Minimum and Maximum are 0 and 2500 respectively. The ER3000 is
shipped with outer loop PID parameters that have been established at the factory to work
well with the regulator in that system, however, in this example we will begin tuning by
setting the parameters as follows:
• Proportional: 200.
• Integral: 0.
• Derivative: 0.
• Integral Minimum: 0.
• Integral Maximum: 0.
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