Mitsubishi Electric MELSEC-Q Series User Manual page 115

(a) Precautions
• When interrupt conditions are always established with "Level Detect" being set to "Detection Method"
Because the interrupt process is performed for each link scan, if the sequence scan time is much longer
than the link scan time, a watchdog timer error may occur in the CPU module due to the prolonged
sequence scan. To avoid this, check the conditions using program and do not use the interrupt settings.
• Before executing an interrupt program
Execute the EI instruction in the main routine program and enable the interrupt. (
the CPU module used (function explanation, program fundamentals))
Main routine
program
I0 interrupt
program
• When multiple interrupts occur simultaneously
The operation may delay.
• When a master/local module is in test mode or offline mode
The interrupt to the CPU module can be performed when a master/local module is in online mode. The
interrupt cannot be performed when a master/local module is in test mode or offline mode.
• Executing an interrupt program at rise or fall of the specified device
Do not execute an interrupt program by using the rise (using the PLS instruction) or fall (using the PLF
instruction) of the specified device because the device change may not be recognized.
A request for the interrupt is issued by turning on RX10.
Ex.
PLS
• When the interrupt cannot be performed
If the changing time of the device used for the interrupt condition is shorter than the transmission delay
time, the device change cannot be detected.
• When using data for an interrupt program
When an interrupt program is being executed, RX/RY/RWr/RWw are not auto refreshed to the device of a
CPU module. Therefore, directly access to the buffer memory of a master/local module by using Intelligent
function module device (Un\G).
• When data link is faulty, a request for the interrupt to a CPU module is not issued.
EI
FEND
I0
IRET
Interrupt pointer
U0\
Since change of RX10 may not be read,
G225.0
this cannot be specified as interrupt condition.
CHAPTER 7 PARAMETER SETTINGS
Enable interrupt.
User's manual for
7
113