The contrast and the microcontroller executes instructions PLC instruction execution mode.
Mapping the parallel branches understanding of the sequential function chart.
PLC and SCM instruction is performed sequentially manner.
PLC execution instruction is divided into three stages.
The cycle comprises a PLC instruction
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Input sample
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Program execution
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Output refresh
If within one sampling cycle instruction. External input change, this change in the current scanning cycle
Is constant, the next scan cycle will change.
It will come out of the problem of double coil PLC.
In fact output value of the coil in the last row of the program,
