Ddc Fixed Setpoint Controller - Siemens SIPART DR22 Manual

1 Technical Description
1.5 Functional description of the structure switches
1.5.4 Controller types (S1, S49 to S53)
wi1
n
o
0/1
wi1
ES
S101
2/3/4/5
SES
FE1
FE2
FE3
see
Fig. 1-5,
page 24
Figure 1-27 Block diagram S1 = 1, fixed setpoint controller with 2 dependent setpoints
1.5.4.4 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 the DDC operation the process computer takes over the
control function, the controller is on standby, i.e. it is followed up to the computer manipulated
variable; the control difference is reset to zero for absolutely bumpless switching by x-tracking if
necessary.
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
during computer operation (S66 = 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 UI-converter of the K-controller is to be used during computer operation to feed the final
control element, the actuating current cutoff must be canceled (S66 = 0).
The DDC mode corresponds to follow-up mode of the other controller types with the difference
that the switching to follow-up mode takes place not via the control signal N but as a function of
52
Int∧CB
Int∧CB
wi1
Int∧CB
c4, c5
wi1 · c4+c5
wi2
factory setting
c4=1, c5=0
c1, c2, c3
x1
x2
x=x1+c1 · (x2 - c2 · x3+c3)
x3
factory setting
c1=c2=c3=0
tFI
Adaptation

DDC fixed setpoint controller

0
1
w - c5
c4
d I d I
* *
II I
A=H∨N∨Si
0000 0000
w
H = Hi ∨He
SA,SE
tS
A
A
S50
0 1
x
I
d
*
II
0000
x1
Manual
S5
2
wI
+
xdI
--
see
W Fig.
1-50,
pg. 90
xI
xI
d I
*
I
x
0000
SIPART DR22 6DR2210
C79000-G7476-C154-03