Instructions; Basic Understanding Of Instructions - Omron CJ2 CPU UNIT SOFTWARE User Manual

5 Understanding Programming
5-6

Instructions

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Basic Understanding of Instructions

Structure of Instructions
Programs consist of instructions. The conceptual structure of the inputs to and outputs from an instruc-
tion is shown in the following diagram.
Power flow (P.F., execution condition)
Instruction condition
Power Flow
The power flow is the execution condition that is used to control the execute and instructions when
programs are executing normally. In a ladder program, power flow represents the status of the exe-
cution condition.
Input Instructions
• Load instructions indicate a logical start and outputs the execution condition.
• Intermediate instructions input the power flow as an execution condition and output the power flow
to an intermediate or output instruction.
Output Instructions
Output instructions execute all functions, using the power flow as an execution condition.
LD power flow
Input block
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Instruction
Flags
Operands Operands
(sources) (destinations)
I/O memory
Outputs the execution
condition.
Outputs the execution
condition.
=
D0
#1215
Power flow for
output instruction
Output block
Power flow (P.F., execution condition) *
Instruction condition *
2
Flag
*1: Input instructions only.
*2: Not output for all instructions.
CJ2 CPU Unit Software User's Manual
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