I/O Instruction Timing - Omron SYSMAC CS Series Programming Manual

Basic Concepts
2-1-9

I/O Instruction Timing

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Differentiated Instructions
The following timing chart shows different operating timing for individual
instructions using a program comprised of only LD and OUT instructions.
B1
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B2 Input
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B3
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B4
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Input
B5
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B6
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B7
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!
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B8
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!
B9
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B10
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B11
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B12
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CPU pro-
cessing
Instruction I/O refresh
executed.
• A differentiated instruction has a flag that tells whether the previous value
is ON or OFF. At the start of operation, the flags for upwardly differenti-
ated instruction (DIFU and @ instructions) are set to ON and the flags for
downwardly differentiated instructions (DIFD and % instructions) are set
to OFF. This prevents differentiation outputs from being output unexpect-
edly at the start of operation.
• An upwardly differentiated instruction (DIFU or @ instruction) will output
ON only when the execution condition is ON and flag for the previous
value is OFF.
Section 2-1
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