Description of Operation
Section
3-2
98
3-2-9 Order
of
Operations
The operation of function blocks is executed in 1) order of operation groups
fixed in the system and 2) order of block addresses in each operation group
in function blocks (having the same operation cycle).
Operation groups fixed in the system are executed in order of the following
function block categories:
1, 2, 3…
1.
System Common blocks
2. Input-only terminals (DI Terminals, AI Terminals) on Field Terminal,
mixed input and output terminals (DI/DO Terminals, AI/AO
Terminals…
1)
3. Receive from all nodes on the Node Terminals
4. Receive terminals of CPU Unit Terminal (DI Terminal from CPU Unit, AI
Terminal from CPU Unit), and receive terminals of Expanded CPU Unit
Terminal (DI Terminal from Expanded CPU Unit, AI Terminal from
Expanded CPU Unit), Receive All Blocks
5. Operation blocks (for example, Alarm/Signal restrictions/Hold, Arithmetic,
Function, Time Function, Signal Selection/Switching, ITEM Setting, Pulse
Train Operation, other and sequence operation)
6. Step Ladder Program
7. Control blocks, External Controller Terminals
8. Output-only terminals (DO Terminal, AO Terminal) on Field terminals
9. Send to Computer terminals on Node Terminals
10. Send from all nodes on Node Terminals
11. Send terminals (DO Terminal from CPU Unit, AO Terminal from CPU
Unit) on CPU Unit Terminals, send terminals (DO Terminal from
Expanded CPU Unit, AO Terminal from Expanded CPU Unit) on
Expanded CPU Unit Terminals, Send All Blocks
1: In the case of mixed input and output terminals, input processing is
executed alternatively with output processing at each single
operation cycle. For this reason, twice the operation cycle of preset
operation cycles is required when compared with input-only and
output-only processes.