Internal Structure Of The Cpu Unit; Overview - Omron SYSMAC CS Series Programming Manual

Internal Structure of the CPU Unit

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Internal Structure of the CPU Unit

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Overview

CPU Unit
User program
The User Program
I/O Memory
PC Setup
The following diagram shows the internal structure of the CPU Unit.
Memory Card
I/O memory
EM file memory
PC Setup and
other parameters
The user program is created from up to 288 program tasks, including interrupt
tasks. The tasks are transferred to the CPU Unit from the CX-Programmer
programming software.
There are two types of tasks. The first is a cyclic task that is executed once
per cycle (maximum of 32) and the other is an interrupt task that is executed
only when the interrupt conditions occur (maximum of 256). Cyclic tasks are
executed in numerical order.
Program instructions read and write to I/O memory and are executed in order
starting at the top of the program. After all cyclic tasks are executed, the I/O
for all Units are refreshed, and the cycle repeats again starting at the lowest
cyclic task number.
I/O memory is the RAM area used for reading and writing from the user pro-
gram. It is comprised of one area that is cleared when power is turned ON and
OFF, and another area that will retain data.
I/O memory is also partitioned into an area that exchanges data with all units
and an area strictly for internal use. Data is exchanged with all units once per
instruction execution cycle using one of two methods depending on the
instruction that is executed.
The PC Setup is used to set various initial or other settings through software
switches.
The program is divided
Task 1
into tasks and the tasks
are executed in order by
task number.
Task 2
Task n
I/O memory, PC Setup,
programs and the EM area
can be saved as files.
DIP switch
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