Omron NY532-5400 Reference Manual page 69

If you specify upward or downward differentiation, the operation depends on the following: the value of
the variable the last time the instruction was executed and the current value of the variable. This is
shown below.
Differentiation specifi-
Instruction
Upward differentiation
LD
Downward differentia-
tion
Upward differentiation
LDN
Downward differentia-
tion
The following figure shows a programming example and timing chart.
A
A
A
↑
A
↑
A
↑
A
↑
Precautions for Correct Use
• An error occurs in the following case and the output value from the last execution is retained.
• You specify an array element for the variable value and the element does not exist.
Example: A BOOL array a[0..5] is defined, but the instruction is executed using a[10] as the vari-
• Do not use these instructions as the rightmost instruction on a rung. If you do, an error occurs on the
Sysmac Studio and you cannot transfer the user program to the Controller.
NY-series Instructions Reference Manual (W560)
Value of variable at last execution and current
cation
FALSE at the last execution → Currently TRUE
Other than the above.
TRUE at the last execution → Currently FALSE
Other than the above.
FALSE at the last execution → Currently TRUE
Other than the above.
TRUE at the last execution → Currently FALSE
Other than the above.
TRUE
A
FALSE
B1
TRUE
B1
FALSE
B2
TRUE
B2
FALSE
B3
TRUE
B3
FALSE
B4
TRUE
B4
FALSE
B5
TRUE
B5
FALSE
B6
TRUE
B6
FALSE
Instruction execution
able.
2 Instruction Descriptions
value of variable
Output value
TRUE
FALSE
TRUE
FALSE
FALSE
TRUE
2
FALSE
TRUE
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