Omron NJ Series User Manual

2 CPU Unit Operation
2-6
NJ-series CPU Unit Software User’s Manual (W501)
 Types of Processing That are Executed with Tasks
The following processing is performed with tasks.
Refer to 5-2-3 Basic Operation of Tasks for details on the processing that is executed with tasks.
 Task Operation
Processing is assigned to tasks. There are three kinds of tasks, as shown in the following table.
They are defined by their execution priorities and execution conditions.
The CPU Unit executes the task with the highest execution priority first. The following operation
example is for the primary periodic task and a periodic task. If the primary periodic task is ready for
execution while a periodic task is in execution, execution of the periodic task is interrupted to allow
execution of the primary periodic task.
Processing Executed with Tasks
Processing Description
I/O refreshing Data I/O for EtherCAT slaves, CJ-series Basic I/O Units, and CJ-series Spe-
cial Units is performed.
User program execution The user programming for sequence control is executed. It also sends com-
mands to the motion control process.
Motion control Motion control is executed based on commands from the user program.
System common process-
ing
System common processing, such as data trace processing and tag data link
processing, is performed.
Type of task
Execution priority (smaller values
indicate higher priority)
Execution conditions
Main processing con-
tent
Primary periodic
task
4
This task has the highest execution
priority.
The primary periodic
task is periodically exe-
cuted.
I/O refreshing, user
program execution,
and motion control
Periodic tasks 16, 17, or 18
Execution is interrupted for execution
of the primary periodic task and for
event tasks that have a higher execu-
tion priority.
A periodic task is peri-
odically executed.
The task period is an
integer multiple of the
task period of the pri-
mary periodic task.
The processing that
can be performed
depends on the execu-
tion priority.
Execution priority 16:
I/O refreshing and user
program execution
Execution priority 17 or
18: User program exe-
cution
Event tasks 8 or 48
Execution is interrupted for execution
of the primary periodic task and for
periodic tasks that have a higher exe-
cution priority.
An event task is exe-
cuted only once when
the specified condition
is met.
User program execu-
tion

Omron NJ Series Specifications

General

Program Capacity	Up to 128 MB
SD Card Slot	Yes
Power Supply Voltage	24 VDC
Motion Control	Yes
USB Ports	1
Operating Temperature	0°C to 55°C
Communication Interfaces	Ethernet/IP, EtherCAT, USB
Safety Function	Optional
Storage Temperature	-20°C to 75°C
Communication Ports	USB
Dimensions	Varies by model
Weight	Varies by model