Omron FQM1-MMA21 Basic Information on Programming, Appendix A, Power Flow, Instruction Conditions

Programming Appendix A

Basic Information on Programming

Basic Information on Instructions

Programs consist of instructions. The conceptual structure of the inputs to and outputs from an instruction is shown in the following diagram.

Input condition		Instruction		Input condition*1
Instruction conditions				Instruction conditions*2
Flags				Flag
				*1: Input instructions only.
	Operands		Operands	*2: Not output for all instructions.
	(sources)		(destinations)

Memory

Power Flow

The power flow is the input condition that is used to control the execution of instructions when programs are executing normally. In a ladder program, power flow represents the status of the input condition.

1.Input Instructions

•Load instructions indicate a logical start and output the input condition.

Outputs the input condition.

•Intermediate instructions input the power flow as an input condition and output the power flow to an inter- mediate or output instruction as an input condition.

Outputs the input condition.

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D00000

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2.Output Instructions

Output instructions execute functions, using the power flow as an input condition.

Input condition for LD

Input condition for output instruction

Input block Output block

Instruction Conditions

Instruction conditions are special conditions related to overall instruction execution that are output by the instructions listed below. Instruction conditions have a higher priority than the input condition when it comes to deciding whether or not to execute an instruction. An instruction may not be executed or may act differently depending on instruction conditions. Instruction conditions are reset (canceled) at the start of each task, i.e., they are reset when the task changes.

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