Pid - Pid Controller - Siemens 353 User Manual

Function Blocks

3.2.68 PID - PID Controller

PID is a proportional + integral controller and one of five
controller types that can be used on a one per loop basis. It
uses external feedback to provide integral action. The
block allows interaction with other function blocks or
external devices, such as pneumatic controllers and shutoff
switches, to eliminate the windup that can occur with other
controller types. Derivative action is provided when the
parameter TD is non-zero. The controller includes an
autotune feature that can be initiated from the operator
faceplate using the QUICK access feature.
When input A is high (1) the controller operates in the
normal auto mode and when low (0) causes reset R to track
(F-GE). This will force the controller output to track the
feedback within the controller limits and allow the
controller to switch back to auto without bumping the
output.
The process range pointer parameter points to another
function block that has range scaling, such as an analog
input that is the process variable. This enables the
controller to normalize the tuning parameters for the
process range. If this parameter is not configured, the
controller will use a range scaling of 0.00-100.00.
Input I, when changed from low (0) to high (1) or from
high to low, will cause the controller to initialize (i.e.
eliminate any proportional gain action during that cycle).
This can be used to prevent bumping the output when changes are made to the setpoint using a switch block.
POWER UP - During a warm or cold power up, the output will be initialized to MINSCALE and all dynamic
elements will be initialized at the current input on the first scan.
Process
Engineering
P
INput units
scaling
RanGe
PoinTeR
+
-
Engineering
S
INput units
scaling
.
Setpoint
3-72
PID Controller
t
+
D S
+
t
D
+ 1
S
D G
Lead
+
e
A
-
1
-
+/
Absolute Value
Absolute Error
BLOCK DIAGRAM
AE
PID CONTROLLER
R
Range
P
Process
Setpoint S
F
Feedback
A
Auto
I
Initialize
R G P T R RanGe PoinTeR
I R A C T
D DIRect ACTing
P G Proportional Gain
T I Time - Integral
T D
Time - Derivative
D G Derivative Gain
M I N S C A L E MINimum SCALE
M A X S C A L E
MAXimum SCALE
D
D P P
E N G U N I T S ENGineering UNITS
A U T O T U N E
AUTOTUNE
% D E V % DEViation
% H Y S % HYSteresis
% S T E P
%
A T D Y N A M AT DYNAMic settings
A T R E S E T AT RESET
P O S T A T
POST Autotune Transfer
I N P U T P INPUT P
I N P U T S INPUT S
I N P T F INPUT F
U
I N P U A INPUT A
T
I N P U T I INPUT I
E S N
Exec. Seq. No.
+
Limit
PG
-3.3 < O < 103.3%
+
Lag
R
1
t
+ 1
I S
Auto
Initialize
UM353-1B
ESN = 000
PID
OR
Output Range
PID
O1 Output
CONTROLLER
AE Absolute Error
AT Warning
AW
....................
loop tag.block tag
(S)
................................ NO/YES
(H)
................... 0.001 to 100.0
(S)
................... 0.001 to 4000 m/r
(S)
............. 0.00 to 100.00 min
(S)
........................ 1.00 to 30.00
(S)
.................................. Real
(H)
................................ Real
(H)
P P
ecimal oint osition (preferred) ........... 0.0.0.0.0.0
(S)
.................6 ASCII Char
(S)
................................... NO/YES
(S)
during Autotune .... AUTO, 2.5 to 25.0 (AUTO)
(S)
during Autotune (S) .. AUTO, 0.5 to 10.0 (AUTO)
output STEP on first Autotune ............ 5% to 40%
(S)
.... Fast, Medium, Slow
(S)
.................................... NO/YES
(S)
................ NO/YES
(S)
.......................
(H) loop tag.block tag.output
.......................
(H) loop tag.block tag.output
.......................
loop tag.block tag.output
(H)
.......................
loop tag.block tag.output
(H)
........................ loop tag.block tag.output
(H)
............................. 001 to 250
(H)
ENG UNITS
scaling
O1
Output 1
inverse scaling
F
Feedback
A
.
I
r3
April 2012
(null)
(NO)
(1.000)
(100.0)
(0.00)
(10.00)
(0.0)
(100.0)
(0.0)
(PRCT)
(YES)
(10)
(M)
(YES)
(NO)
(null)
(null)
(null)
(null)
(null)