West Control Solutions Pro-16 - Manual (Page 16)

Operation
9499-040-93811 / 59537-1 Page 16 of 88 Pro-16
3.7.2 Optimization after start-up or at the set-point
There are two methods of optimization; either after start-up or at the set-point. As control
parameters are always optimal only for a limited process range, various methods can be
selected dependent of requirements. If the process behavior is very different after start-up
and directly at the set-point, parameter sets 1 and 2 can be optimized using different
methods. Switch-over between parameter sets dependent of process status is possible (see
page 23).

Optimization after start-up: (see page 17)
Optimization after start-up requires a certain separation between process value and set-
point. This separation enables the controller to determine the control parameters by
evaluation of the process whilst progressing to the set-point. This method optimizes the
control loop from the start conditions to the set-point, whereby a wide control range is
covered. We recommend selecting optimization method “Step attempt after start-up” with
tunE = 0 first. Unless this attempt is completed successfully, we then recommend a
“Pulse attempt after start-up”.

Optimization at the set-point: (see page 17)
For optimizing at the set-point, the controller outputs a disturbance variable to the process.
This is done by briefly changing the output variable. The process value changed by this
pulse is evaluated. The detected process parameters are converted into control parameters
and saved in the controller. This procedure optimizes the control loop directly at the set-
point. The advantage is in the small control deviation during optimization.
3.7.3 Selecting the method ( ConF/ Cntr/ tunE)
Selection criteria for the optimization method:
tunE Step attempt
after start-up
Pulse attempt
after start-up Optimization at
the set-point
= 0 sufficient set-point
reserve is provided sufficient set-point
reserve is not provided
= 1 sufficient set-point
reserve is provided
sufficient set-point
reserve is not provided
= 2 Only step attempt after
start-up required
Sufficient set-point reserve:
inverse controller: process value is (10% of
rnGH - rnGL) below the set-point
direct controller: process value is (10% of rnGH - rnGL) above the set-point