West Control Solutions Pro-16 - Manual (Page 17)

Operation
9499-040-93811 / 59537-1 Page 17 of 88 Pro-16
3.7.4 Step attempt after start-up
Condition: - tunE = 0 and sufficient set-point reserve provided
or - tunE = 2
The controller outputs 0% correcting variable or Y.Lo and waits, until the process is at
rest (see start-conditions on page 15).
Subsequently, a correcting variable step change to 100% or
Y.Hi is output.
The controller attempts to calculate the optimum control parameters from the process
response. If this is done successfully, the optimized parameters are taken over and used for
line-out to the set-point.
With a 3-point controller, this is followed by “cooling”.
After completing the 1st step as described, a correcting variable of -100% or
Y.Lo
(100% cooling energy) is output from the set-point. After successful determination of the
“cooling parameters”, the controller will proceed to the setpoint using the optimized
parameters.
3.7.5 Pulse attempt after start-up
Condition: - tunE = 1 and sufficient set-point reserve provided.
The controller outputs 0% correcting variable or Y.Lo and waits, until the process is at
rest (see start conditions page 15)
Subsequently, a short pulse of 100% or
Y.Hi is output (Y=100%) and reset.
The controller attempts to determine the optimum control parameters from the process
response. If this is completed successfully, these optimized parameters are taken over and
used for stabilized to the set-point.
With a 3-point controller, this is followed by “cooling”.
After completing the 1st step as described and stabilized to the set-point, correcting
variable "heating" remains unchanged and a cooling pulse (100% cooling energy) is output
additionally. After successful determination of the “cooling parameters”, the optimized
parameters are used for stabilized to the set-point.
3.7.6 Optimization at the set-point
Conditions:

A sufficient set-point reserve is not provided at self-tuning start (see page 16).

tunE is 0 or 1

With Strt = 1 configured and detection of a process value oscillation by more
than ± 0,5% of ( rnG.H - rnG.L) by the controller, the control parameters
are preset for process stabilization and the controller realizes an optimization at the
set-point (see figure “Optimization at the set-point”).

when the step attempt after power-on has failed