Outline
Section
1-1
10
The following describes each of the functions of the Loop Control Unit.
1) External
I/O
WARNING
Do not perform writing operations on the same I/O memory address allocated
to contact outputs or analog outputs between the Loop Control Unit and the
CPU Unit.
If writing is performed on the same address, the externally connected load
may function unexpectedly, causing an injury.
Analog I/O or Contact I/O
Analog signals or contact signals are input and output constantly (at each
operation cycle) between the Analog I/O Unit or Basic Unit on the same PC
and the CPU Unit I/O memory. At this time, the user is not required to be
aware of I/O memory addresses as the Field Terminal block is used.
With analog I/O, only the unit number of the Analog I/O Unit is set. With
contact I/O, however, the leading allocated address in I/O memory must be
set.
At each I/O
refresh
At each I/O
refresh
Analog Input Unit
CPU Unit
I/O memory
Loop Control Unit
Analog Output Unit
Field Terminal
block
At each
opera-
tion
cycle
At each
opera-
tion
cycle
Note
The Loop Control Unit uses the Field Terminal block (regardless of the user
program on the CPU Unit) to read and write areas allocated for contact or
analog signals. So, do not perform write operations on the same allocated
areas between the Loop Control Unit and the CPU Unit.