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Computing the Cycle Time Section 10-4
Parallel Processing Mode (CJ-H CPU Units Only)
10-4-2 Cycle Time Overview
Normal Processing Mode
The cycle time depends on the following conditions.
• Type and number of instructions in the user program (in all cyclic tasks
that are executed during a cycle, and within interrupt tasks for which the
execution conditions have been satisfied).
• Type and number of Basic I/O Units
• Type and number of Special I/O Units, CPU Bus Units, and type of ser-
vices being executed.
• Specific servicing for the following Units
• Data link refreshing and the number of data link words for Controller
Link and SYSMAC LINK Units
NO
YES
Power ON
Startup
initialization
Checks Unit
connection status
Program Execution
Cycle
Peripheral
Servicing Cycle
Check user program
memory, etc.
Check OK?
Services
peripherals.
Overseeing
processing
Program execution
cycle time
Check OK?
Execute user
program (i.e., READY
cyclic tasks).
Program
completed?
Wait for specified
cycle time.
Calculates cycle
time.
Refreshes I/O.
Services peripherals.
Overseeing
processing
Program
execution
Cycle time
calculations
I/O refreshing
ERR/ALM
indicator lit or
flashing
Lit: Fatal error
Set error flags.
Check hardware,
etc.
Flashing:
Non-fatal
error
Periph-
eral
servic-
ing
Periph-
eral
servic-
ing
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