Omron CJ - PROGRAMMING MANUAL 12-2009 Programming Manual page 78

Basic Concepts
Downwardly Differentiated Instructions (Instruction preceded by %)
38
• Output instructions: The instruction is executed only during the cycle in
which the execution condition turned OFF (ON → OFF) and is not exe-
cuted in the following cycles.
(%) Downwardly dif-
ferentiated instruction
■
Timing Chart
Bit A
Bit A
Operation
of SET
• Input Instructions (Logical Starts and Intermediate Instructions): The
instruction reads bit status, makes comparisons, tests bits, or perform
other types of processing every cycle and will output the execution condi-
tion (power flow) when results switch from ON to OFF. The execution con-
dition will turn OFF the next cycle.
Downwardly differentiated instruction
■ Timing Chart
Bit A
Bit A
Bit B
Note Unlike the upwardly differentiated instructions, downward differentia-
tion variation (%) can only be added to LD, AND, OR, SET and RSET
instructions. To execute downward differentiation with other instruc-
tions, combine the instructions with a DIFD or a DOWN instruction.
NOT can be added to instructions only when using a CS1-H, CJ1-H,
CJ1M, or CS1D CPU Unit.
• Input Instructions (Logical Starts and Intermediate Instructions): The
instruction reads bit status, makes comparisons, tests bits, or perform
other types of processing every cycle and will output an OFF execution
Example
Executes the SET instruction once
when CIO 000102 goes ON to OFF.
%SET
Example
Will turn ON when the CIO 000103 switches from
ON → OFF and will turn OFF after one cycle.
Bit B
1 cycle
Section 2-1
%SET