Description of Operation
Section
3-2
95
Function block G
Example: Basic PID
Loop Control Unit
Function block B
Example: Alarm
Function block A
Example: CPU Unit
Terminal
Function block C
Example: Step
Ladder Program
System common
operation cycle
Example: 1 s
Specific operation
cycle
Example: 100 ms
System common operation cycle
Specific operation cycle of only a certain
function block
Function block D
Example: Terminal
to Computer
Function block E
Example: Analog
Function block F
Example: Square
Root
The operation cycle of specific function blocks can be specified to be shorter
than the default 1-second operation cycle in the following instances:
To increase the refresh cycle of analog input/output and the PID operation
execution cycle in a pressure or flowrate control loop
In this case, set the operation cycle of all function blocks that are used in a
single loop (for example, analog input, square root and other operations,
PID control and analog output) to the same shorter value.
To increase the execution timing, for example, in Remote/Local switching
To reduce the minimum resolution (time accuracy) of Timer and Counter
blocks on the Loop Control Unit
The minimum resolution (time accuracy) of Timer and Counter blocks on
the Loop Control Unit is the same as the operation cycle. So, in this case,
set the operation timer of the Timer block (Block Model 205) and Counter
block (Block Model 208) to shorter values.