West Control Solutions KS98-1 - Manual (Page 268)

Second correcting value
Similar to processing, switch-over to a second preset correcting value Y2 is possible. Switching over is done via digi-
tal input y/y2. Whether Y2 has safety functions, or whether it is only a pre-defined start position in defined process
conditions is determined only by the use and integration into an automation concept.
a
Second correcting value Y2 is evaluated with priority. When switching over to Y2 is done at one point
(interface or digital control input ‘ y/y2‘), switching over at the other point is not possible.
Correcting variable limits
Parameters Ymin and Ymax determine the limits
of the correcting variable range within 0...100 %.
With three-point and continuous controller „split
range“, the correcting variable limits are within -100
... +100 %. Parameters
Ymin and Ymax are used
to specify fixed correcting variable limits.
External correcting variable limiting
(override control)
Dependent of ‘ COVC‘ setting, the lowest
( OVC-), the highest (OVC+) or lowest and hig-
hest correcting value ( OVC+/OVC-) can be li-
mited by analog input signals.
Override control is used where bumpless
switch-over to another controller when reaching de-
fined process conditions and mainly according to ot-
her criteria is required. The basic principle is that
two controllers act on the same motor actuator.
9499-040-82711
III-268 Process value calculation
y
t
Ymax
Ymin
100%
0%
Fig. 91 Fixed correcting variable limits
y
Ymin
100%
0%
OVC+
t
>1%
Fig.:92 Maximum value limiting
y
t
Ymax
100%
0%
OVC-
>1%
Fig.:93 Minimum value limiting
y
100%
0%
OVC
+
t
>1%
OVC
-
Fig.:94 Mini- and Maximum value limiting