ABSTRACT
Programmable logic controller (PLC), is a special-purpose computer for
industrial control design.Because it is easy to design and programming, running
can be estimated, even in the worst of circumstances can also maintain normal
working, so widely used in industrial control.
Analysis of this issue in the mainstream of PLC system structure, working
principle and on the basis of common instructions, design based on single-chip
micro-PLC, is aimed at small to replace small PLC in the control system, for more
flexible application on the basis of the programme and in ensuring the reliability
of significantly reducing costs.
This topics design of system in hardware design Shang reference PLC of
system structure, in single tablets machine of Foundation Shang extended has rich
of perimeter device, implementation has PLC of most function module, including
central processing unit (CPU), and power module, and oscillation circuit, and
reset circuit, and digital volume I/O, and serial communications,, and design has
specifically of entered output points processing circuit, makes system has good of
anti-interference characteristics and drive ability.Micro-PLC based on single-chip
design, providing a more flexible software and hardware solutions, and
dramatically reduce the cost of control system, has a high practical
value.Experimental part and the practical application of software design is divided
into sections.Experimental section is written in c and assembler, test the feasibility
of the PLC control panel.Practical application of part to make programming
simpler by GX Developer software writing ladder, then PWM-HEX language
conversion software to convert it to a single-chip, then through the STC_ISP
software to download it to a STC90C52 based on a single-chip micro-PLC control
panels.
Key words micro-PLC, singlechip,GX Developer,PWM-HEX , STC89C52
