Omron CP1H CPU Operation Manual page 109

CP1H CPU Unit Operation
User Program
I/O Memory
Parameter Area
PLC Setup
(3) • CX-Programmer operations can be used to transfer data from RAM to
the Memory Cassette or from the built-in flash memory to the Memory
Cassette.
• When the power supply is turned ON, data is transferred from the
Memory Cassette to the built-in flash memory.
The user program consists of up to 288 tasks, including interrupt tasks. Each
task is programmed from the CX-Programmer and then transferred to the
CPU Unit.
There are two types of tasks: cyclic tasks and interrupt tasks. Cyclic tasks are
executed once each cycle and interrupt tasks are executed only when the
interrupt conditions are met. There can be up to 32 cyclic tasks and up to 256
interrupt tasks. Cyclic tasks are executed in the order of the task numbers.
Instructions programmed in the tasks are executed in order from the first
instruction and then I/O memory is refreshed. When all cyclic tasks have been
executed, I/O refreshing with PLC Units is performed and then the cyclic tasks
are executed again starting from the one with the lowest task number. This is
called the cyclic scan method.
The I/O memory area is a RAM area read and written by the user. Some parts
of the I/O memory are cleared when the power is interrupted. Other parts are
maintained. There are parts that used for data exchange with PLC Units and
parts that are used internally.
There are two ways to refresh the parts of I/O memory used for data
exchange with PLC Units: Once each program execution cycle and immedi-
ately when needed when executing specific instructions.
In addition to the I/O memory used as instructions operands by the user, there
is also a separate memory area that can be manipulated only from the CX-
Programmer. This area, called the parameter area, contains the following.
• PLC Setup
• Routing tables (when CJ-series Units are used)
• Unit Setups for CPU Bus Units
The PLC Setup contains configuration parameters that can be set by the user
to define the basic specifications of the CPU Unit. Included are serial port set-
tings, a minimum cycle time setting, and other parameters. For details, refer to
the CX-Programmer Operation Manual.
Section 2-3
75