Siemens SIPART DR22 Manual page 81

Manual
As a result the main controller controls down its manipulated variable and with it the heating
performance and imposes the manipulated variable limit on the main controller. The case
temperature drops below the limiting setpoint and the limiting controller drives to the
manipulated variable limit via the now positive control difference. It is controlled to a constant
core temperature.
The disconnection therefore always takes place when the controlled variable of the
non-intervening controller becomes more positive than the set setpoint (xd negative), then
the manipulated variable limited to maximum is dropped below, i.e. a maximum value limiting
of the controlled variables takes place. The manipulated variable maximum value limiting
corresponds in this example to a minimum value selection of the manipulated variables.
Depending on the structure switch position (S1 = 7 or 8) and the set controller direction of
effect (normal: +Kp or reversed: -Kp) the limiting direction of the controlled variables is
reversed (Minimum- or Maximum value limits):
Manipu- corres-
lated ponds
variable variable to y- to y-
S1 S1
limiting selec-
direction tion
7 yA Max
7 yA Max
8 yE Min
8 yE Min
7 yA Max
7 yA Max
8 yE Min
8 yE Min
Table 1-15 Limiting direction of the controlled variables depending on S1 = 7/8 and controller direction
of effect
The direction of effect of the transmitter, actuator and controlled system are included in the
determining of the controller direction of effect (see chapter 4.1, page 215). As a rule,
limiting controllers and main controllers have the same direction of effect so that the second
part of the table is irrelevant.
SIPART DR22 6DR2210
C79000-G7476-C154-03
Controller direction
of effect
Main Limit ing
Main controller
control- control-
ler I ler II
norm +Kp norm +Kp xdI > 0,
rev -Kp rev -Kp xdI < 0,
norm +Kp norm +Kp xdI < 0,
rev -Kp rev -Kp xdI > 0,
norm +Kp rev -Kp xdI > 0,
rev -Kp norm +Kp xdI < 0,
norm +Kp rev -Kp xdI < 0,
rev -Kp norm +Kp xdI > 0,
1.5 Functional description of the structure switches
1.5.4 Controller types (S1, S49 to S53)
Disconnection at
Limiting
I controller II
x I< wI xdII > 0, xII < Sb
xI > wI xdII < 0, xII > Sb
xI > wI xdII < 0, xII > Sb
xI < wI xdII > 0, xII < Sb
xI < wI xdII < 0, xII > Sb
xI > wI xdII > 0, xII < Sb
xI > wI xdII > 0, xII < Sb
xI < wI xdII > 0, xII > Sb
1 Technical Description
Limiting of the
controlled
variables to
xI xII
Min Min
Max Max
Max Max
Min Min
Min Max
Max Min
Max Min
Min Max
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