Omron CS1W-LC001 Operation Manual page 37

Outline
Function Block Operations (independent of and asynchronous with
CPU Unit)
The function blocks on the Loop Control Unit are cyclically executed
according to fixed operation cycles. Operations are executed asynchronously
with the user program on the CPU Unit.
The operation cycle is one of 0.1, 0.2, 0.5, 1 or 2 seconds ( Á 1), and can be
specified to each function block. (The default operation cycle is one second
for each function block.)
Operation is started when the PC is turned ON regardless of the CPU Unit
operation mode.
Á 1 The execution cycle for commands in the Step Ladder Program block
(Block Model 301) on the Loop Control Unit is one of 0.1, 0.2, 0.5, 1 or 2
seconds for each operation cycle in the Step Ladder Program block. The
command execution cycle is longer than the cycle time of commands in
the Step Ladder Program on the CPU Unit.
External I/O (via the CPU Unit I/O memory)
The Loop Control Unit actually updates external I/O data from each unit via
CPU Unit I/O memory at each operation cycle of the Field Terminal block.
Constant Data Exchange with CPU Unit (by Function block)
The Loop Control Unit refreshes data I/O with specified CPU Unit I/O
memory areas at each operation cycle of the CPU Unit Terminal block or the
Expanded CPU Unit Terminal block.
On-demand Data Exchange with CPU Unit (by FINS command
issued to Unit)
The CPU Unit can read and write Loop Control Unit data by issuing the FINS
command to the Loop Control Unit by the CMND (DELIVER COMMAND)
command in the Step Ladder Program whenever necessary.
CPU Unit Status Notification (by reflecting in System Common
block)
The status of the CPU Unit (operation mode, fatal error, etc.) is reflected in
the System Common block on the Loop Control Unit. If necessary, the Loop
Control Unit extracts data from this System Common block.
Loop Control Unit Status Notification (by allocated CIO Area)
The status of the Loop Control Unit is reflected on the CPU Unit at the CIO
Area allocated as the CPU Bus Unit. Note, however, that this status is
reflected every second and not at the I/O refresh cycle.
Section 1-1
17