Chapter 9 Pid Operation Instruction; Overview - Mitsubishi Electric MELSEC iQ-R Series Programming Manual

9
PID OPERATION INSTRUCTION
PID operation instruction and PID control instruction
There are two types of instructions for PID control.
Type Application
PID operation This instruction is used to perform PID control using auto
instruction tuning.
PID control This instruction is used to perform PID control equal to that of
instruction the MELSEC-Q series and MELSEC-L series.
The following table lists the specifications comparison between PID operation instruction and PID control instruction.
Item
PID operation method
Sampling period/sampling time
Number of control loops
Auto tuning
9.1

Overview

This section describes an overview of PID control using the PID operation instruction.
PID operation instruction
The PID operation instruction calculates the manipulated value (MV) from the process value (PV) by combining the P action
(proposal action), I action (integral action), and D action (derivative action) to get closer to the set value (SV).
■Alarm output function
This function turns on the alarm output for the variations of input (process value) and output (manipulated value).
■Output upper/lower limit value setting
This function suppresses the increase of integral terms in PID control by setting the output upper/lower limit values.
■Auto tuning function
This function automatically sets the proportional gain (K
performed in two methods: limit cycle method and step response method.
■Operation method of the PID operation instruction
The instruction performs PID operation in the velocity type or the process value derivative type.
9 PID OPERATION INSTRUCTION
1134
9.1 Overview
PID operation instruction
Inexact differential
1 to 32767ms
1 loop per instruction
Enabled (limit cycle method and step response
method)
), integral time (T
P
Reference (Overview) Reference (Details)
Page 1134 Overview Page 1145 PID Operation Instruction
Page 1149 Overview Page 1158 PID Control Instructions
(Inexact Differential),Page 1170 PID
Control Instructions (Exact Differential)
PID control instruction
Inexact differential/exact differential
10 to 60000ms
32 loops maximum
Disabled
), and derivative time (T
I
). The auto tuning is
D