Omron CJ2 CPU UNIT SOFTWARE User Manual page 67

Peripheral Servicing
Peripheral servicing involves servicing non-scheduled events for external devices. This includes both
events from external devices and service requests to external devices.
Most peripheral servicing for CJ-series PLCs involves FINS commands. The amount of time specified
in the system is allocated to each type of servicing and executed every cycle. If all servicing cannot be
completed within the allocated time, the remaining servicing is performed the next cycle. If peripheral
servicing is delayed too much, increase the fixed servicing time in the PLC Setup to a value larger than
10% using the CX-Programmer.
Peripheral Servicing Time
With the default peripheral servicing time setting, 10% of the preceding cycle time is assigned to the
total peripheral service. Therefore, the peripheral servicing time depends on the preceding cycle
time.
Set a time longer than 10% of the cycle time using Fixed Servicing Time in the PLC Setup from the
CX-Programmer when peripheral servicing is delayed because too many cycles is required to com-
plete it. Keep in mind that increasing the servicing time will also increase the cycle time.
Types of Peripheral Servicing
Units
Event servicing for Special I/O Units • Non-scheduled servicing for FINS commands from Special I/O Units
Event servicing for CPU Bus Units
Peripheral USB port service
Serial port service
Communications port servicing
File access servicing
Online editing servicing
Backup servicing
Additional Information
Servicing time is allocated to Special I/O Units, CPU Bus Units, the peripheral USB port, serial
ports, file access, and communications ports.
If servicing is separated over many cycles, delaying completion of the servicing, set the same
allocated time (same time for all services) rather than a percentage under execute time settings
in the PLC Setup.
CJ2 CPU Unit Software User's Manual
and CPU Bus Units (e.g., requests to start external interrupt tasks)
• Non-scheduled servicing for FINS commands from the CPU Unit to the
above Units.
• Non-scheduled servicing for FINS or Host Link commands received via
the peripheral USB or serial ports from Programming Devices, PTs, or
host computers (e.g., requests to transfer programming, monitoring,
forced-set/reset operations, or online editing)
• Non-scheduled servicing from the CPU Unit transmitted from the periph-
eral USB or serial port (non-solicited communications)
• Servicing to execute network communications, serial communications,
or file memory access for the SEND(090)/SEND2(491),
RECV(098)/RECV2(492), CMND(490)/CMND2(493), or
PMCR(260)/PMCR2(264) instructions using communications ports
(internal logic ports).
• Servicing to execute background execution using communications ports.
File read/write operations for Memory Cards or EM file memory.
Servicing to backup contents edited with online editing in the built-in flash
memory when online editing is being processed.
Servicing to backup changed contents in the built-in flash memory when
there is a change in programming or parameters.
3 CPU Unit Operation
Servicing
3
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