Omron NJ-series User Manual page 186

Additional Information
Reference: Reading the Values of Axis Variables in the Priority-16 Periodic Task
• If an axis variable is read in the priority-16 periodic task, the most recent values of the axis
variable when the program execution for the priority-16 periodic task started are read. These
values show the results of motion control processing in the immediately proceeding primary
periodic task.
• Values are not written to axis variables when motion control instructions are executed in the
priority-16 periodic task. They are written in the motion control processing (MC) section of the
next primary periodic task.
Primary
periodic task
Priority-16
periodic task
The most recent values of the axis variables
are read at the start of execution of the
programs in the priority-16 periodic task.
• The results of execution of motion control instruction in the previous priority-16 periodic task
are read as the value of the axis variable in the next priority-16 periodic task.
Primary
periodic task
Priority-16
periodic task
NJ-series CPU Unit Software User's Manual (W501)
Primary period (t)
IO UPG MC IO UPG MC
Task period 1 (e.g., t × 3)
Axis
UPG
variables
FB
read.
Motion control instructions
executed.
Values are not written to axis variables
when motion control instructions are
executed in the priority-16 periodic task.
Primary period (t)
IO UPG MC IO UPG MC
Task period 1 (t × 3)
Axis
UPG
variables
FB
read.
Motion control instructions executed.
IO UPG MC IO UPG MC
They are written in the motion control
processing section in the next primary
periodic task.
IO UPG MC IO UPG MC
Standby
Axis
UP
variables G
read.
The results of execution in the
previous priority-16 periodic task
are read as the values of the axis
variables.
5 Designing Tasks
IO UPG MC
IO UPG MC
FB
Motion control
instructions executed.
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