Scheduling Dependent On The Actual Value Signal Or Output Variable Signal - Samson Trovis 6400 Mounting And Operating Instructions

Operation

6.13.2. Scheduling dependent on the actual value signal or output variable signal

Scheduling dependent on the actual value signal has to be selected with configuration block
C51-3, whereas scheduling dependent on the output variable signal has to be configured with
C51-4. In the cascade control mode, C52-3 or C52-4 can be set to implement adaptation for
the master controller loop. Note that scheduling is only supported in systems with self-regula-
tion.
The following parameters must be set before starting the adaptation algorithm:
All parameters as for single adaptation (see section 6.13.1.) and additionally:
GW K Min. limit for the adaptation range in %
2
GW K Max. limit for the adaptation range in %
2
K Number of sections (maximum 7)
4
For scheduling dependent on the actual value signal, the control station must be put to the
AUTOMATIC mode.
Scheduling has the objective to compensate for measurable, static non-linearities occurring in
a process. This scheduling procedure is used to determine the optimum controller settings for
definable sections of a selected adaptation range. The operator can choose among two
scheduling procedures: 1) scheduling dependent on the controlled variable (CO 51-3) or 2)
scheduling dependent on the output variable (CO 51-4). As already described above, limits
for the adaptation range have to be entered, meaning, for example a range for the controlled
variable. In addition, the number of sections into which this adaptation range shall be divided
have to be defined. In the scheduling procedure, the controller calculates a factor for each of
these sections, which modifies the proportional-action coefficient K
stored as parameters K
located in the middle of each section. The control parameters are linearly interpolated between
these reference points. The values calculated before the first and after the last reference point
are maintained constant.
First, the scheduling algorithm runs through the steps described in section 6.13.1.. Then, the
process control station goes to the lower limit of the defined adaptation range and waits for the
controlled system to become stationary. As soon as the system is stationary, the control station
accesses the first operating point. This is done abruptly (step change) with scheduling dependent
on the output variable and regularly (controlled) with scheduling dependent on the controlled
variable. The operating points are located exactly on the limits of the individual sections. After
having gone to the operating point, the process control station waits again for the controlled
system to become stationary. Subsequently, the adaptation algorithm calculates the factor for
the respective section. The procedure described above is repeated for each section.
The last part of the scheduling procedure can be followed on the display of the process control
station as described in Fig. 36 .
As for single adaptation, the scheduling steps either run automatically (AdP Aut) one after the
other or each step can be accessed individually (nb-idF-Scd), see. p. 46.
Also, it is possible to set all parameters to be calculated in the ADAPTATION PARAMETER level.
to K . The reference points for the scheduling procedure are
1 7
AdP level (adaptation of the control parameters)
These section factors are
p.
51