Mitsubishi Electric MELSEC iQ-R Series, Programming Manual

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10 PID CONTROL INSTRUCTIONS
10.1 Overview
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• PID control data can be registered or changed every scan of the program. Whenever the data are registered
or changed, execute the PIDINIT instruction. If not executed, the registered or changed data are not used
when the PIDCONT instruction is executed.
• Note that the PIDINIT instruction does not need to be executed if the PID control data are changed for the
specified loop by using the PIDPRMW instruction.
PID control data
PID control data is used to set the reference values for PID operation. The set values need to be registered to the CPU
module by using the PIDINIT instruction before PID operation by the PIDCONT instruction starts. The PID control data can be
set to a word device area with any numbers. Note that all the data for the number of loops used must be set in the area with
consecutive device numbers.
For data assignment, refer to the following.
• Inexact differential: Page 1160 S(P).PIDINIT
• Exact differential: Page 1172 PIDINIT(P)
PID control data are classified into two types: data common to all loops and data for each loop.
Type Item Description Setting range Processing when set data is
out of the valid range
Data common to all
loops Number of loops used Number of loops where PID operation is
performed 1 to 32 An error occurs, and PID operation
is not performed for all loops.
Number of loops in
one scan Number of loops to be used in one PID
operation when multiple loops reach the
sampling period at a same time 1 to 32