Robur Direct Digital Controller, Инструкция по установке, использованию и программированию

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Direct Digital Controller
Direct Digital Controller fw 4.013 – Ed. 01/2013
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When the values of the number of stages in each category are set initially, or if they are subsequently varied,
it is also necessary to modify the setting of the other parameters; refer to paragraph
Default values of the
parameters and indications for correct choice of their values (categories 1 and 3)” on page 103 and in
particular Table 2.
Prevention time, enabling integral and prevention integral of a category, description of the regulation
algorithm
These three parameters are also defined for each category, which affect the regulation algorithm used by the
system to maintain the temperature of the water inside the differential period.
The regulator operates by switching the machine that constitutes the various stages of the various categories
on and off. When the regulator is operating on the stages of a given category, it uses the values of the three
parameters corresponding to this category. This allows to optimise the regulation on the basis of the features
of the specific category (number and power of the stages, type of heat generator).
Successively, the regulation algorithm is illustrated via an example of evolution of the water temperature
through time. It is assumed that the system is made up from two stages belonging to a unique category and
that the initial condition is within machines all off and temperature of the water within the differential band. In
the following description, refer to Figure 16.
A.
Zone 1 of the graph in Figure 16: while the temperature of the water remains within the differential band
centred around the set point, the regulator keeps all machines off.
B. Point 2 : when the falling water temperature, exits the differential band, the regulator switches the
machines, which constitute the first stage of the category at highest priority, on.
Note: subsequently, switch-on of the machines that constitute a stage data will be defined for brief
switch-on of the stage
C. Zone 3 : if the energy supplied by the first stage is such to make the temperature of the water rise quickly
inside the differential band and keep it there, the regulator does not perform other interventions and keeps
the first stage on.
D. Point 4 and Zone 5 : if the energy supplied by the first stage causes the water temperature to rise above
the differential band, the regulator switches the first stage off and keeps it off in zone 5.
E. Point 6 and Zone 7: in this case, the energy supplied by the first stage is not sufficient to cause quick rise
of the water temperature. When the first stage has been switched back on in point 6, the regulator, after a
delay equal to the value inserted for the “
prevention time ” parameter, starts to calculate the energy
deficit, represented by the dotted area in zone 7. If the dotted area should reach the value set for the
“
enabling integral ” parameter, the regulator “would release” the second stage and switch it on. In the
case represented in zone 7, instead, the temperature of the water rises within the differential band before
the dotted area reaches this value, therefore the regulator does not switch the second stage on, but keeps
the first stage on, as the temperature of the water remains within the differential band.
F. Point 8 and Zone 9 : in the same way as the case described in D, the regulator switches the first stage in
point 8 off and keeps it off in zone 9.
G. Points 10 and 11 and zone 12 : the situation is similar to that described in E, but in this case, after the
delay equal to “ prevention time ”, the dotted area that represents the energy deficit reaches the value set
for the “ enabling integral ” parameter, therefore the regulator “releases” the second stage and switches it
on (in point 11); it keeps it on in zone 12, i.e. up to when the temperature of the water is below or within
the differential band.
H. Point 13 and zone 14: in the same way as the case described in D, for the first stage, if he energy
supplied by the second stage causes the water temperature to rise over the differential band, the regulator
switches the second stage off in point 13 and starts to calculate the excess energy, represented by the
dotted area in zone 14. If the dotted area should reach the value set for the “
prevention integral ”
parameter, the regulator “would block” the second stage and would switch the first stage off. In the case
represented in zone 14, instead, the temperature of the water returns within the differential band before
NOTE