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Programming Concepts Section 1-1
• 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 ON execution
condition (power flow) when results switch from OFF to ON. The execu-
tion condition will turn OFF the next cycle.
• 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
condition (power flow stops) when results switch from OFF to ON. The
execution condition will turn ON the next cycle.
Downwardly Differentiated
Instructions (Instruction
preceded by %)
• 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.
• 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.
Note Unlike the upwardly differentiated instructions, downward differen-
tiation variation (%) can only be added to LD, AND, OR, SET and
RSET instructions. To execute downward differentiation with other
instructions, combine the instructions with a DIFD or a DOWN in-
struction.
Example
Upwardly differentiated input instruction
ON execution condition created for one
cycle only when CIO 1.03 goes from
OFF to ON.
1.03
Upwardly differentiated input instruction
1.03
Example
OFF execution condition created for one
cycle only when CIO 1.03 goes from
OFF to ON.
1.02
Example
%SET
Executes the SET instruction once
when CIO 1.02 goes ON to OFF.
(%) Downwardly dif-
ferentiated instruction
1.03
Example
Downwardly differentiated instruction
Will turn ON when the CIO 1.03 switches
from ON to OFF and will turn OFF after
one cycle.
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