Siemens SIPART DR22 Manual page 61

Manual
-- Cascade control
A command controller, e.g. a fixed setpoint controller (with the main controlled variable)
feeds the external setpoint of a slave controller with its manipulated variable (with the
auxiliary controlled variable, disturbance variable) and this the actuator. This gives faster
control of the main controlled variable in the event of changes in the auxiliary controlled
variable, e.g. furnace temperature control (furnace temperature, main controlled variable)
with different flow of the medium to be heated (auxiliary controlled variable).
-- Synchronized controls
A master controller feeds several synchronized controllers simultaneously whose individual
setpoints can be set in a ratio to each other by the constants c4 and c5 and then drag the
controlled variables accordingly (controlled variable synchronization).
-- Internal/External switching
The setpoint switching takes place via a logic link RC = Int∧CB and its negation
(see table 1--11, page 61 and table 1--12, page 62). Both control signals can be set statically
to 1 or 0 (int via S49, CB via S24) in addition to their normal functions as Shift key or control
signal with the states 1 and 0, see chapter 1.5.3 fig. 1-16, page 37 and fig. 1-17, page 38.
The factory setting is Int = 1 (S49 = 0) and CB=1 (S24 = -1), so that in the factory setting
the internal setpoint wi is always active and cannot be switched!
With this setting facility it is possible to perform the switching only dependent on Int (S49=2,
S24= -1) or only dependent on CB (S49=1, S24=1 to 14) as a slave controller with Internal/
External-switching. If the switching facility is blocked in External position (S49=1, S24=-1),
the controller operates as a follow-up controller without Internal/External-switching (see table
1-2, page 43).
-- Display of the external setpoint w
With the Shift key (12) the digital w-display can be switched to the external setpoint w
the digital x-display to the main controlled variable x1 in the display level II (display range I
must be set, display range II is automatically set the same). The active setpoint and the
active actual value are still indicated on the analog displays.
The LEDs Controller I/Controller II signal the display level.
Flashing signals that the displayed external setpoint is not identical with the active setpoint.
Steady light signals that the displayed and active setpoints are identical.
SIPART DR22 6DR2210
C79000-G7476-C154-03
1.5 Functional description of the structure switches
E
1 Technical Description
1.5.4 Controller types (S1, S49 to S53)
and
E
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