Pid Control - Mitsubishi Electric MELSEC-Q series Programming Manual

PID control

Applicable CPU
QCPU
Programmable controller CPU
Basic High Performance
*1
 
*1 First five digits of serial No. are 04122 or later
[SET DATA]
■Description and data type
Set Data
S
■Usable device
Set Data Usable Devices
Internal Devices
(System, User)
Bit

S
[FUNCTION]
• When the PIDCONT(P) instruction is executed, the sampling cycle is measured and PID operation is performed.
• With the PIDCONT(P) instruction, PID operation is carried out on the basis of the set value (SV) and process value (PV) in
the I/O data area set to the device number specified by
manipulated value (MV) area of the I/O data area.
• PID operation is executed in response to the execution of the PIDCONT(P) instruction appearing first after the set time for
sampling cycle has elapsed. ( Page 50 Sampling cycle)
• During PID control, turn ON the control command to execute the PIDCONT(P) instruction in every scan. If not, PID
operation in a normal sampling cycle will not available. It is not possible to execute the PIDCONT(P) instruction more than
once in one scan. If it is executed more than once in one scan, PID operation cannot be performed in a normal sampling
cycle.
• The PIDCONT(P) instruction is not available for use in an interrupt program, fixed scan execution type program or low
speed execution type program. If the PIDCONT(P) instruction has been used in an interrupt program, fixed scan execution
type program or low speed execution type program, PID operation cannot be performed in a normal sampling cycle.
• For , designate the first number of the device numbers that are designated as the I/O data area. If file registers (R) are
S
designated for the I/O data area, do not set memory protect ON for the file registers (R). If memory protect is set ON,
correct PID operation will be precluded, although no error will occur. ( Page 51 I/O Data)
• Execute the PIDCONT(P) instruction in every scan even while the manual manipulated value (MV
the manual control mode. The bumpless function cannot be executed if the PIDCONT(P) instruction has not been
executed. ( Page 31 Bumpless changeover function)
9 COMPLETE DERIVATIVE PID CONTROL INSTRUCTIONS AND PROGRAM EXAMPLES
74
9.1 PID Control Instructions
Universal

Description
First number of devices allocated to I/O device area
File Register
Word

Process CPU

MELSECNET/10 (H) Special
Direct J\ Function
Module
Bit Word
U\G

or later, and the operation result is stored into the automatically
S
LCPU
Redundant CPU
 
Data Type
16-bit binary
Index
Register Zn
MAN
QnA Q4AR
 
Constant Other
) is being output in