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F356_PID_PWM
PID processing is performed to keep the process value PV as close as possible to the set point
Description
value SP. In contrast to F355_PID_DUT (see page 941), this instruction enables a PWM output
(on-off output). Auto-tuning is also available to automatically calculate the PID control data Kp, Ti,
and Td.
Abbreviations used when describing PID processing
Abbreviation
PV
SP
MV
Ts
Ti
Td
Kp
AT
General programming information
1. When the input at Run is executed, the data in the argument
ParametersNonHold is initialized.
If you want a value in the DUT to use non-default values, write the values into the DUT using a MOVE
instruction, for example, which must be triggered continuously by a TRUE condition.
2. F356_PID_PWM must be executed once and only once per scan. Therefore, do
not execute F356_PID_PWM in interrupt programs or loops.
3. Do not turn the execution condition to FALSE during PID processing. Otherwise,
PID processing will be disabled.
4. If you do not want parallel PWM output cycles, e.g. to enable control of multiple
objects, delay the start-up times accordingly, e.g. by employing a timer instruction.
Example:
PID processing with optional PWM output
What it stands for
Also know as
Process value
Actual value, measured value
Set point value
Target value, set value
Manipulated value
Output value, manipulated
variable
Sampling time
Cycle time
Integral time
Derivative time
Proportional gain
Auto-tuning
Process control instructions
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945
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