Response Electronics CL6011B Especificaciones descargar pdf (Pagina 33)

3Ć13 Theory of Operation: Point Processing

Original Ć June 1990 CE4.2:CL6211

There are two proportional gains associated with the adaptive gain PCA.

The controller base gain is the gain that is tuned into the controller and

modified by the adaptive gain control calculations. The active gain is the

actual gain used by the controller. Each adaptive gain variable changes

its adaptive gain factor for the loop. The total active gain is the product

of all of the adaptive gain factors multiplied by the nominal base gain.

The total active gain is limited by the Gain Limit configuration item. The

gain limit is a high limit when it is set above the base gain value and a

low limit when it is set below the base gain value. The gain limit provides

a hard" limit that the active gain cannot exceed.

Process Variable Adaptive Gain Ċ When the active gain is being

modified by the process variable, it will change based upon the process

variable value, the value of the upper and lower break points, and the

upper and lower gain factors.

The upper and lower break points are adjustable values that divide the

process variable span into three regions as shown in Figure 3Ć5 on page

3Ć14. The lower gain factor determines the gain when the process

variable is below the lower break point. The farther below the break

point the process variable is, the more the process variable adaptive gain

factor changes. The upper gain factor determines the gain when the

process variable is above the upper break point. The farther above the

break point the process variable is, the greater the change in the

adaptive gain factor. The process variable active gain factor is 1.0 when

the process variable is between the upper and lower break points.

The resulting active gain changes linearly based on the difference

between the break point and the adapting variable. The rate of change

of the active gain is established by the respective gain factor. The gain

factor is defined as the ratio of the base gain to the active gain when the

adaptive variable is 10% of span from the break point. The gain factor is

used to calculate the adaptive gain factor, which is computed as follows:

AGF = 1 - [(1 - GF)(DEV)/10]

The adaptive gain factor is then used to calculate the loop's active gain.

A gain factor greater than one causes the active gain to increase as the

adaptive variable moves away from the break point. A gain factor less

than one causes the active gain to decrease as the adaptive variable

moves away from the break point. The effect of gain factor changes is

illustrated in Figure 3Ć5 on page 3Ć14.

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Response Electronics CL6011B Especificaciones Pagina 33