Siemens SIPART DR22 Manual page 77

Manual
In this controller type a master controller (Controller II) and a follow-up controller as a com-
manded ratio controller (Controller I) are interconnected in a ratio cascade.
(Applications see S1 = 4)
-- Master controller
The master controller has the same structure with respect to the setpoint switching as the
follow-up controller S1 = 3. It is therefore a fixed setpoint controller with the possibility of ex-
ternal setpoint preset via the analog signal, the serial interface or as an incremental setpoint
via the control signals
is also possible here, in the case of a computer failure (CB from 1 ! 0) to continue working
with the last computer setpoint (followed-up wi) or with the safety setpoint SH (selection by
S51). The master controller cannot be switched to manual operation but the follow-up con-
troller can be switched to the internal setpoint. x-tracking in A-operation is possible by selec-
tion with S50 = 1. The follow-up of the inactive setpoint to the active setpoint can be
switched off by S52 = 1.
-- Follow-up controller
The follow-up controller is a ratio controller as described under S1 = 4. To disconnect the
cascade the Internal/External key (2) (Int I) can be used to switch between the internal ratio
factor wvi and the external ratio factor wv
master controller (yaII). The internal operation of the follow-up controller corresponds to
manual operation of the master controller.
xv-tracking is possible in A-operation by selection with S50 = 1. Setpoint limitings can be
performed via limiting of the manipulated variable of the master controller and possibly by
limiting the commanding process variable x2 I in the freely connectable input range (S4 = 1).
The follow-up of the master controller and xv-tracking in A-operation and the follow-up of the
internal ratio factor wvi in external operation and in x-tracking (A) always takes place so that
switching is bumpless.
Table 1-14, page 72 and the statements on x-tracking of the cascade controls apply accord-
ingly when wi is replaced by wvi and w
SIPART DR22 6DR2210
C79000-G7476-C154-03
Δw. Selection is made with w

, which is equal to the manipulated variable of the
E
by wv
E
1.5 Functional description of the structure switches
1.5.4 Controller types (S1, S49 to S53)
II and S101. In computer coupling it
SL
.
E
1 Technical Description
75