Siemens S5-100U - Page 246

Integrated Blocks and Their Functions S5-100U
Figure 9-7. Block Diagram of the PID Controller
TI
R
TD
Z
k
-Z
k-1
Sum-
ming
unit
Limiter
OG
UG
a a a
a
a
a
a
a
a
a a a
-
a a a
a
a
a
a
a
a
a a a
+
a a a a
a
a a
a
a a a a
+
a a a
a
a
a
a a a
+
a a a a
a
a a
a
a a a a
+
a a a
a
a
a
a a a
+
a a a a
a
a a
a
a a a a
+
a a a
a
a
a
a a a
0
a a a
a
a
a
a a a
Y
a a a
a
a
a
a
a
a
a a a
0
a a
a a
a a
a a
1
a a a
a
a
a
a a a
1
a a a
a
a
a
a a a
0
a a a a
a
a a
a
a a a a
dY
a a a a a
a
a a a
a
a
a a a
a
a a a a a
XW
a a a
a
a
a
a a a
+
a a a
a
a
a
a
a
a
a a a
+
a a a a
a
a a
a
a
a a
a
a a a a
dY
YH, dYH
a a a a a a a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a a a a a a a
STEU
Bit 0
BGUG
BGOG
a a a
a
a
a
a
a
a
a a a
0
Z
W
X
XZ
a a a
a
a
a
a
a
a
a a a
1
K
a a a a a a a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a a a a a a a
STEU
Bit 1
a a a a a a a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a a a a a a a
STEU
Bit 5
a a a a a a a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a a a a a a a
STEU
Bit 2
Manual
function
a a a a a a a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a a a a a a a
STEU
Bit 3
a a a a a a a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a
a a a a a
a
a a a a a a a
STEU
Bit 4
0
YA,
dYA
a a a
a
a
a
a a a
0
a a a
a
a
a
a a a
1
0
a a
a a
a a
a a
1
Table 9-6. Legend for the Block Diagram of the PID Controller
K
R
TA
TN
TV
TI
TD
W
STEU
YH, dYH
Z
XW
X
XZ
Y, dY
BGOG
BGUG
YA, dYA
Designation
Proportional coefficient: K>0 direct acting
K<0 reverse acting
R parameter (usually 1000)
Scan time
Integral-action time
Derivative-action time
Constant TI TI=Scan time TA/Integral action time TN
Constant TD TD=Derivative action time TV/Scan time TA
Setpoint
Control word
Output value: YH Control Word Bit 3=0
dYH Control Word Bit 3=1
Disturbance variable
System deviation
Actual value
Substitute value for system deviation
Manipulated variable, manipulated increments
Upper limit of the manipulated variable
Lower limit of the manipulated variable
Output word : YA Control Word Bit 3=1
dYA Control Word Bit 3=0
Explanation
9-16 EWA 4NEB 812 6120-02