3 Functional description of the structure switches
3.4 Controller types (S1, S42 to S45)
Manual
68
SIPART DR21
C73000-B7476-C143-08
3.4.4
DDC-Fixed setpoint controller (S1 = 2)
The DDC-controller has the job of taking over the control circuit as bumpless as possible in the
case of a computer failure. During DDC operation- the process computer takes over the control
function, the computer is in stand-by-mode and is tracked to the computer manipulated vari-
able. If necessary the control difference is set to zero by x-tracking for absolutely bumpless
switching.
In K-controller circuits, the actuating current can be output parallel by the computer periphery to
achieve full redundancy. In this case the actuating current of the K-controller is switched off dur-
ing computer operation (S52 = 1). If the actuating current of the computer is also to be switched
off during controller operation, the two currents simply need to be added by OR-diodes. This
OR-diode is integrated in the current outputs of the SIPART-controllers.
If the U/I-converter of the K-controller is to be used during computer operation to feed the final
control element, the actuating current cutoff must be cancelled (S52 = 0).
The DDC-mode corresponds to tracking mode of the other controller types with the difference
that the switching to tracking mode takes place not via the control signal N but as a function of
the control signal CB and the Internal/External key:
DDC-mode
≙
RC = Int
∧
CB = 1
Y
W
x3
x1
x2
P I D
W
+
-
X
wi
x=x1+c1 · (x2 - c2 · x3+c3)
X
0000
y
a
+c6 · z
z
y
H
y
a
y
N
00
x - TRACKING
y
N
y
ES
SES
Int
∧
CB
tS
Figure 3-9 Control principle S1 = 2
Содержание SIPART DR21
Страница 1: ...SIPART DR21 C73000 B7476 C143 08 1 SIPART DR21 6DR 210 Edition 08 2010 Manual ...
Страница 2: ...SIPART DR21 C73000 B7476 C143 08 2 ...
Страница 16: ...1 General Part Fundamental control technology terms Manual 16 SIPART DR21 C73000 B7476 C143 08 ...
Страница 148: ...4 Installation 4 2 Electrical Connection Manual 148 SIPART DR21 C73000 B7476 C143 08 ...
Страница 180: ...5 Operation 5 5 CPU self diagnostics Manual 180 SIPART DR21 C73000 B7476 C143 08 ...
Страница 192: ...6 Commissioning 6 7 Manual setting of the control parameters Manual 192 SIPART DR21 C73000 B7476 C143 08 ...
Страница 234: ...9 General explanation of abbreviations for SIPART DR Manual 234 SIPART DR21 C73000 B7476 C143 08 ...
Страница 242: ...Manual 242 SIPART DR21 C73000 B7476 C143 07 ...