Mitsubishi Electric MELSEC iQ-R Series User Manual page 440

Instructions that affect the status of another instruction when executed
When one of the following instructions is executed and the status of another instruction changes, the new status will not be
tracked to the other system. When the system switching is performed during execution of an instruction, execute the
instruction again as required.
Classification
Program execution control instructions
File register operation instructions
Timing check instruction
SFC control instruction
Instructions causing different operation results between both systems
This section describes the instruction that causes different operation results between the control system and standby system
after system switching.
■PID control instructions
When using the following PID control instructions, include the number of device points used by the systems in tracking target
data. Otherwise, the instructions cause different operation results between the control system and standby system after
system switching.
n: Total number of loops
Classification
PID control instructions (Inexact
differential)
PID control instructions (Exact
differential)
Ex.
When the number of loops is eight, the PIDINITP instruction needs 2 + 8  10 = 82 words and the PIDCONT instruction needs
10 + 8  18 = 154 words. Thus, include D1000 to D1081 and D1100 to D1253 in tracking target data.
26 REDUNDANT FUNCTION
438
26.11 Precautions on Programming
Disabling interrupt programs
Enabling interrupt programs
Disabling interrupt programs with specified priority or
lower
Interrupt program mask
Disabling/enabling the specified interrupt pointer
Switching the file register block number
Changing the file register file name
Generating timing pulses
Target block switching
Registering the PID control data to
the CPU module
PID operation
Registering the PID control data to
the CPU module
PID operation
Instruction symbol
DI
EI
DI
IMASK
SIMASK
RSET(P)
QDRSET(P)
DUTY
BRSET
Instruction symbol
S(P).PIDINIT
S(P).PIDCONT
PIDINIT(P)
PIDCONT(P)
Number of device points used
2 + n  4
10 + n  23
2 + n  10
10 + n  18