
B-63983EN/02 1.OVERVIEW OF PMC
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1.4 EXECUTION OF SEQUENCE PROGRAM
Sequence programs in the Ladder language are executed in the order of
instructions coded in the ladder diagrams.
Fig. 1.4 shows how a sequence program is executed.
Sequence program
memory
Sequence
program
input
Control target such as machine tool
Input circuit
Output circuit
Internal relay (RAM)
Fig. 1.4 Sequence program execution by PMC
The RD instruction causes the CPU to read the signal of the input
circuit at address X0.0 and set the read data in the operation register.
Next, the AND instruction causes the CPU to AND the set data with the
internal relay state at address R10.1 and set the result in the operation
register. The CPU then executes the subsequent instructions at high
speed, and the operation result is output to the output circuit at address
Y0.0.