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Process control instructions
PID_FB
This implementation allows you to set the parameters of F355_PID directly using arguments:
Description
Data types
Input variables (VAR_INPUT):
Variable
Automatic
Forward
I_PD
SP
PV
Kp
Ti
Td
Ts
LowerLimit
UpperLimit
Input/output variable (VAR_IN_OUT):
MV
952
PID processing instruction
Data type
Function
BOOL
FALSE: Manual setting of MV possible
TRUE: Automatic PID controlled MV
FALSE: Inverse control (heating)
TRUE: Forward control (cooling)
FALSE: PI-D control
TRUE: I-PD control
INT
Set point value, range 0-10000
Process value, range 0-10000
Proportional gain, range: 1-9999, unit: 0.1
Integral time, range: 1-30000, unit: 0.1s
Derivative time, range: 1-10000, unit: 0.1s
Sampling time, range: 1-6000, unit: 0.01s
MV lower limit, range: 0-10000
MV upper limit, range: 1-10000
Manipulated value
Auto-tuning is not possible using PID_FB. For this, use PID_FB_DUT (see
page 953).
The value for MV can be assigned externally either when the program is
initialized or when the value of Automatic is FALSE.
In order to achieve maximum resolution and minimum dead time beyond
LowerLimit and UpperLimit, their values should, if possible, cover the
entire range of 0–10000.
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