Omron CP - PROGRAMMING MANUAL 05-2007 Programming Manual page 653

Data Control Instructions
Execution
condition
Performance Specifications
Item
PID control method
Number of PID control loops
Sampling period
PID constant Proportional band
Integral constant
Derivative constant
Set value
Measured value
Manipulated variable
Calculation Method
Set value
(target value)
Measured
value (PV)
Block Diagram for Target
Value PID with Two
Degrees of Freedom
620
From Analog Input Unit
APR
D1000
Analog input value
D2000
PID
D2000
D2500
D3000
APR
D1500
D3000
Analog output value
To Analog Output Unit
--- Target value filter-type two-degrees-of-freedom PID method (forward/
reverse)
--- Unlimited (1 loop per instruction)
0.01 to 99.99 s
P 0.1 to 999.9%
Tik 1 to 8191, 9999 (No integral action for sampling period multiple, 9999.)
Tdk 0 to 8191 (No derivative action for sampling period multiple, 0.)
SV 0 to 65535 (Valid up to maximum value of input range.)
PV 0 to 65535 (Valid up to maximum value of input range.)
MV 0 to 65535 (Valid up to maximum value of output range.)
Calculations in PID control are performed by the target value filtered control
with two degrees of freedom.
Target value filter
1 + (1 – ) Ti/ +
1 + Ti/
–
When overshooting is prevented with simple PID control, stabilization of dis-
turbances is slowed (1). If stabilization of disturbances is speeded up, on the
other hand, overshooting occurs and response toward the target value is
slowed (2).
When target-value PID control with two degrees of freedom is used, on the
other hand, there is no overshooting, and response toward the target value
and stabilization of disturbances can both be speeded up (3).
Control Data
C (D1000):
C+1 (D1001):
C+2 (D1002):
C+3 (D1003):
C+4 (D1004):
Control Data
C+6 (D2506):
@8@8
Valid number of bits: 16 (0000 to FFFF Hex)
Valid number of bits: 16 (0000 to FFFF Hex)
Control Data
C (D1500):
C+1 (D1501):
C+2 (D1502):
C+3 (D1503):
C+4 (D1504):
Specifications
Proportional + integral elements
+
Kp
Kp +
Ti/
Preceding derivative-
type elements
.
Kp Td/
.
1 + Td/
Section 3-17
0000 Hex (binary with one table)
1770 Hex (Xm)
0000 Hex (Yo)
1770 Hex (X1)
FFFF Hex (Y1)
0000 Hex (binary with one table)
FFFF Hex (Xm)
0000 Hex (Yo)
FFFF Hex (X1)
1770 Hex (Y1)
Manipulated variable
–
Kp: Proportional constant
Ti: Integral time
Td: Derivative time
: Sampling period
: 2-PID parameter
: Incomplete derivative coefficient