Sabio 2010D, Руководство по эксплуатации

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Internal UV Ozone Photometer Page 9-21
Ozone Servo Control Adjustments
When Ozone Servo Control is selected in the Photometer
Parameters screen, the Model
2010D
utilizes PID control in order
to control the ozone generator based on the Photometer's
measurements.
The ozone servo control loop is adjusted or
"tuned" at the factory for optimum performance when the
Photometer's inlet is connected to the 2010
D
's output
manifold and when both the photometer and ozone generator are
calibrated. If the photometer is connected elsewhere, for
example to an external sample manifold, it will be necessary
to re-tune the loop by adjusting these constants.
Many books have been written about control theory and PID control
and about setting the three main constants of the PID equation:
the Proportional, Integral and Derivative constants. The process
of setting these constants is called "tuning" and is considered
by many to be an art rather than a science.
Although a thorough discussion of control theory and the tuning
of PID loops is outside the scope of this manual, a few pointers
and tips may give a user unfamiliar with PID control a chance of
successfully tuning the 2010
D
's servo loop using a trial-and-
error approach. In general, adjusting the PID constants is a
lengthy and painstaking process that should be avoided if
possible, however for those brave hearts that want to attempt it,
here are a few general tips, pointers and suggestions:

If at all possible, use the standard configuration with the
Photometer's inlet attached via a short length of Teflon
tubing to the 2010
D
's inlet manifold. In this configuration,
it should not be necessary to alter the factory tuning
constants.

Be sure the ozone generator is calibrated such that its output
matches the 2010
D
's photometer. The factory tuning assumes
that when the ozone generator is commanded to produce an ozone
concentration when servo control is disabled, the photometer
will measure that concentration within a few percent.
Before attempting any changes, write down (or print using the
report button) the factory settings in all three pages of the
Photometer Parameters screen.