Mitsubishi Electric MELSEC Q Series Owner's manual

MELSEC-Q/L/QnA Programming Manual
(PID Control Instructions)

1
SAFETY PRECAUTIONS
(Read these precautions before using this product.)
Before using this product, please read this manual and the relevant manuals carefully and pay full attention to safety to handle
the product correctly.
The precautions given in this manual are concerned with this product only. For the safety precautions of the programmable
controller system, refer to the user's manual for the CPU module used.
In this manual, the safety precautions are classified into two levels: " WARNING" and " CAUTION".
Under some circumstances, failure to observe the precautions given under " CAUTION" may lead to serious
consequences.
Observe the precautions of both levels because they are important for personal and system safety.
Make sure that the end users read this manual and then keep the manual in a safe place for future reference.
[Design Precautions]
WARNING
●Configure safety circuits external to the programmable controller to ensure that the entire system
operates safely even when a fault occurs in the external power supply or the programmable controller.
Failure to do so may result in an accident due to an incorrect output or malfunction.
(1) Emergency stop circuits, protection circuits, and protective interlock circuits for conflicting
operations (such as forward/reverse rotations or upper/lower limit positioning) must be configured
external to the programmable controller.
(2) When the programmable controller detects an abnormal condition, it stops the operation and all
outputs are:
• Turned off if the overcurrent or overvoltage protection of the power supply module is activated.
• Held or turned off according to the parameter setting if the self-diagnostic function of the CPU
module detects an error such as a watchdog timer error.
(3) All outputs may be turned on if an error occurs in a part, such as an I/O control part, where the
CPU module cannot detect any error. To ensure safety operation in such a case, provide a safety
mechanism or a fail-safe circuit external to the programmable controller. For a fail-safe circuit
example, refer to "General Safety Requirements" in the MELSEC-L CPU Module User's Manual
(Hardware Design, Maintenance and Inspection).
●Configure a circuit so that the programmable controller is turned on first and then the external power
supply. If the external power supply is turned on first, an accident may occur due to an incorrect output
or malfunction.
WARNING Indicates that incorrect handling may cause hazardous conditions, resulting in
death or severe injury.
CAUTION Indicates that incorrect handling may cause hazardous conditions, resulting in
minor or moderate injury or property damage.

2
[Design Precautions]
[Startup and Maintenance Precautions]
WARNING
●When connecting a peripheral with the CPU module or connecting an external device, such as a
personal computer, with an intelligent function module to modify data of a running programmable
controller, configure an interlock circuit in the program to ensure that the entire system will always
operate safely. For other forms of control (such as program modification or operating status change)
of a running programmable controller, read the relevant manuals carefully and ensure that the
operation is safe before proceeding. Especially, when a remote programmable controller is controlled
by an external device, immediate action cannot be taken if a problem occurs in the programmable
controller due to a communication failure. To prevent this, configure an interlock circuit in the program,
and determine corrective actions to be taken between the external device and CPU module in case of
a communication failure.
CAUTION
●Before performing online operations (especially, program modification, forced output, and operating
status change) for the running CPU module from the peripheral connected, read relevant manuals
carefully and ensure the safety. Improper operation may damage machines or cause accidents.

3
CONDITIONS OF USE FOR THE PRODUCT
(1) Mitsubishi programmable controller ("the PRODUCT") shall be used in conditions;
i) where any problem, fault or failure occurring in the PRODUCT, if any, shall not lead to any major or serious accident;
and
ii) where the backup and fail-safe function are systematically or automatically provided outside of the PRODUCT for the
case of any problem, fault or failure occurring in the PRODUCT.
(2) The PRODUCT has been designed and manufactured for the purpose of being used in general industries.
MITSUBISHI SHALL HAVE NO RESPONSIBILITY OR LIABILITY (INCLUDING, BUT NOT LIMITED TO ANY AND ALL
RESPONSIBILITY OR LIABILITY BASED ON CONTRACT, WARRANTY, TORT, PRODUCT LIABILITY) FOR ANY
INJURY OR DEATH TO PERSONS OR LOSS OR DAMAGE TO PROPERTY CAUSED BY the PRODUCT THAT ARE
OPERATED OR USED IN APPLICATION NOT INTENDED OR EXCLUDED BY INSTRUCTIONS, PRECAUTIONS, OR
WARNING CONTAINED IN MITSUBISHI'S USER, INSTRUCTION AND/OR SAFETY MANUALS, TECHNICAL
BULLETINS AND GUIDELINES FOR the PRODUCT.
("Prohibited Application")
Prohibited Applications include, but not limited to, the use of the PRODUCT in;
• Nuclear Power Plants and any other power plants operated by Power companies, and/or any other cases in which the
public could be affected if any problem or fault occurs in the PRODUCT.
• Railway companies or Public service purposes, and/or any other cases in which establishment of a special quality
assurance system is required by the Purchaser or End User.
• Aircraft or Aerospace, Medical applications, Train equipment, transport equipment such as Elevator and Escalator,
Incineration and Fuel devices, Vehicles, Manned transportation, Equipment for Recreation and Amusement, and
Safety devices, handling of Nuclear or Hazardous Materials or Chemicals, Mining and Drilling, and/or other
applications where there is a significant risk of injury to the public or property.
Notwithstanding the above, restrictions Mitsubishi may in its sole discretion, authorize use of the PRODUCT in one or
more of the Prohibited Applications, provided that the usage of the PRODUCT is limited only for the specific
applications agreed to by Mitsubishi and provided further that no special quality assurance or fail-safe, redundant or
other safety features which exceed the general specifications of the PRODUCTs are required. For details, please
contact the Mitsubishi representative in your region.

4
CONTENTS
SAFETY PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
CONDITIONS OF USE FOR THE PRODUCT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
MANUALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
RELEVANT MANUALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
GENERIC TERMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
CHAPTER 1 GENERAL DESCRIPTION 10
1.1 PID Processing Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
CHAPTER 2 SYSTEM CONFIGURATION FOR PID CONTROL 12
2.1 Applicable CPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
CHAPTER 3 PID CONTROL SPECIFICATIONS 14
3.1 PID Control by incomplete derivative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Performance specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
PID operation block diagram and operation expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
PID control instruction list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2 PID Control by Complete Derivative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Performance specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
PID operation block diagram and operation expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
PID control instruction list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
CHAPTER 4 FUNCTIONS OF PID CONTROL 25
4.1 Outline of PID Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2 Functions of PID Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Operation method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Forward operation and reverse operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Proportional operation (P operation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Integral operation (I operation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Derivative operation (D operation). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
PID operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4.3 Other Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Bumpless changeover function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
MV upper/lower limit control function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Function for transfer to the SV storage device for the PV in manual mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Changing the PID control data or input/output data setting range (for QCPU and LCPU) . . . . . . . . . . . . . . . . . 33
CHAPTER 5 PID CONTROL PROCEDURE 34
5.1 PID Control Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Number of loops to be used and the number of loops to be executed in a single scan . . . . . . . . . . . . . . . . . . . 49
Sampling cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
5.2 I/O Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
CHAPTER 6 PID CONTROL INSTRUCTIONS 56
CHAPTER 7 HOW TO READ EXPLANATIONS FOR INSTRUCTIONS 58

5
CONTENTS
CHAPTER 8 INCOMPLETE DERIVATIVE PID CONTROL INSTRUCTIONS AND
PROGRAM EXAMPLES 60
8.1 PID Control Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
PID control data settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
PID operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Operation stop/start of designated loop no.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Parameter change at designated loop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
8.2 PID Control Program Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
System configuration for program examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Program example for automatic mode PID control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Program example for changing the PID control mode between automatic and manual . . . . . . . . . . . . . . . . . . . 69
CHAPTER 9 COMPLETE DERIVATIVE PID CONTROL INSTRUCTIONS AND
PROGRAM EXAMPLES 72
9.1 PID Control Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
PID control data settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
PID control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Monitoring PID control status (QnACPU only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Operation stop/start of designated loop no.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Parameter change at designated loop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
9.2 PID Control Program Examples (for QCPU and LCPU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
System configuration for program examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Program example for automatic mode PID control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Program example for changing the PID control mode between automatic and manual . . . . . . . . . . . . . . . . . . . 84
9.3 PID Control Program Examples (QnACPU only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
System configuration for program examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Program example for automatic mode PID control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Program example for changing the PID control mode between automatic and manual . . . . . . . . . . . . . . . . . . . 92
APPENDICES 96
Appendix 1 Processing Time List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Appendix 2 Anti-Reset Windup Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
INDEX 101
INSTRUCTION INDEX 103
REVISIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105
WARRANTY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106

6
MANUALS
The manuals related to this product are listed below.
In necessary, order them by quoting the details in the tables below.
RELEVANT MANUALS
Before reading this manual, refer to the user's manual of the used CPU module or the QnACPU Programming Manual
(Fundamentals), and confirm which programs, I/O processing, and devices can be used with the used CPU module.
Manual name Manual number
(Model Code)
QnUCPU User's Manual (Function Explanation, Program Fundamentals)
Describes the functions, programming procedures, devices, etc. necessary to create programs. (Sold separately)
SH-080807ENG
(13JZ27)
Qn(H)/QnPH/QnPRHCPU Users Manual(Function Explanation, Program Fundamentals)
Describes the functions, programming procedures, devices, etc. necessary to create programs. (Sold separately)
SH-080808ENG
(13JZ28)
MELSEC-L CPU Module User's Manual (Function Explanation, Program Fundamentals)
Describes the functions, programming procedures, devices, etc. necessary to create programs.
SH-080889ENG
(13JZ35)
QnACPU Programming Manual (Fundamentals)
Describes how to create programs, the names of devices, parameters, and types of program. (Sold separately)
IB-66614
(13JF46)
MELSEC-Q/L Programming Manual (Common Instructions)
Describes how to use sequence instructions, basic instructions, and application instructions. (Sold separately)
SH-080809ENG
(13JW10)
QnACPU Programming Manual (Common Instructions)
Describes how to use sequence instructions, basic instructions, and application instructions. (Sold separately)
SH-080810ENG
(13JW11)
QnACPU Programming Manual (Special Function)
Describes the dedicated instructions for special function modules available when using the Q2ACPU(S1), Q3ACPU, and
Q4ACPU. (Sold separately)
SH-4013
(13JF56)
QnACPU Programming Manual (AD57 Instructions)
Describes the dedicated instructions for controlling an AD57(S1) type CRT controller module available when using the
Q2ACPU(S1), Q3ACPU, or Q4ACPU. (Sold separately)
IB-66617
(13JF49)
MELSEC-Q/L/QnA Programming Manual (SFC)
Describes the system configuration, performance specifications, functions, programming, debugging, and error codes for SFC
(MELSAP3) programs. (Sold separately)
SH-080041
(13JF60)
MELSEC-Q/L Programming Manual (MELSAP-L)
Describes programming methods, specifications, and functions for SFC (MELSAP-L) programs. (Sold separately)
SH-080076
(13JF61)
MELSEC-Q Programming/Structured Programming Manual (Process Control Instructions)
Describes the dedicated instructions for process control. (Sold separately)
SH-080316E
(13JF67)
MELSEC-Q/L Programming Manual (Structured Text)
Describes programming using the structured text language. (Sold separately)
SH-080366E
(13JF68)

7
When QCPU is used
When LCPU is used

8
When QnACPU is used