
1. SEQUENCE PROGRAM
CREATING PROCEDURE
B–61863E/15
PMC SEQUENCE PROGRAM
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This is paragraph outlines functions of a sequence program before
explaining the programming work.
A sequence program is a program for sequence control of machine tools
and other systems.
A program is defined as a processing procedure to enable CPU to execute
arithmetic processing.
This program is converted into a format (machine language instructions)
to enable CPU to execute decoding and arithmetic processing, and stored
into the RAM or ROM memory.
The CPU reads out instructions of the program stored into the memory
at high speed every instruction, and executes the program by arithmetic
operation.
The programming of a sequence program begins with the production of
a ladder diagram which serves as a processing procedure for arithmetic
processing by CPU.
This ladder program is produced using PMC instructions.
After producing the ladder diagram, the processing sequence of this
ladder diagram is converted into machine language instructions, and
stored into the memory (program input).
Conversion into the machine language instructions and storage into the
memory are done by the PMC programmer. The PMC programmer is a
function to produce a program.
The sequence program being stored into the memory is sequentially read
out into the PMC’s CPU every instruction at high speed and executed.
Fig. 1.3 shows this relation.
The CPU reads out input circuit signals of address X0.0 by RD X0.0
instruction, and sets them into an operation register. Then, the CPU
executes AND operation with internal relay states at address R10.0
according to the AND R10.1 instruction, and sets these results into the
operation register.
The CPU executes instructions at high speed and outputs arithmetic
results to the address Y0.0 output circuit.
1.3
WHAT IS A
SEQUENCE
PROGRAM?