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PLC's & HMI's - Industrial Control
HMI's (Human-Machine Interfaces) are devices that allow a person to communicate with computers and the computers back to
the person. Such devices include the mouse, keyboard, monitor, touch-screens, musical keyboards, rotary controls, switches
(you get the idea), though these are not usually referred to as HMI's. Really the more common forms of HMI's are as simple as
button and status light panels or more complex touch-screen video interfaces that allow input from the operator and inform the
operator of system status through symbolic displays on the screen. HMI's have evolved over the years into specially designed
touch-screens for the most part. These are used most of the time in the field of industrial control where the HMI's are designed
to integrate with the specialized computers in that industry, called PLC's (Programmable Logic Controllers) and allow the
engineers to program, monitor and adjust controls and sensors. The PLC's have inputs (from various types of sensors) and
outputs (to various types of controls) that keep things operating properly in an automated fashion. Many of these systems
include a graphic display of the equipment that is being controlled so it's easy to see what's going on at a glance, and can also
be programmed to warn users when things go outside acceptable parameters.
This is a kind of simplified explanation of PLC and HMI uses but hopefully peaks someone's interest and desire to investigate further. I also mention this because these PLC's and HMI's are available to hobbyists at reasonable cost from some sources. I have used them myself in a project or two, like a hazard warning system I designed and installed while I was still employed in the work force. I have a few in my personal collection to experiment with also.
Most operate on a kind of graphic symbolic software platform called "Ladder Logic". You can learn the basics of ladder logic in an afternoon and generate simple 'ladder' programs to perform tasks based on specific input states. I'll leave it at that and if you are interested you can do some research on ladder logic on your own.
There are SO MANY web pages and videos of ideas and applications for PLC's, microcontrollers and SBC's that there is no shortage of ready-made projects for the casual hobbyist. You can find plenty to help you whether you're a beginner or intermediate level at the use of these devices. I'm not super experienced with microcontrollers so this site will tend to be closer to a medium hobby level. There are some semi-PLC devices that make great hobby experiment PLC learning devices made by Comfile Technologies that are worth checking out. They program in a combination of BASIC and Ladder, perfect for the experimenter. I also have a page on them here.
At some point I will add more here showing how these things work.
This is a kind of simplified explanation of PLC and HMI uses but hopefully peaks someone's interest and desire to investigate further. I also mention this because these PLC's and HMI's are available to hobbyists at reasonable cost from some sources. I have used them myself in a project or two, like a hazard warning system I designed and installed while I was still employed in the work force. I have a few in my personal collection to experiment with also.
Most operate on a kind of graphic symbolic software platform called "Ladder Logic". You can learn the basics of ladder logic in an afternoon and generate simple 'ladder' programs to perform tasks based on specific input states. I'll leave it at that and if you are interested you can do some research on ladder logic on your own.
There are SO MANY web pages and videos of ideas and applications for PLC's, microcontrollers and SBC's that there is no shortage of ready-made projects for the casual hobbyist. You can find plenty to help you whether you're a beginner or intermediate level at the use of these devices. I'm not super experienced with microcontrollers so this site will tend to be closer to a medium hobby level. There are some semi-PLC devices that make great hobby experiment PLC learning devices made by Comfile Technologies that are worth checking out. They program in a combination of BASIC and Ladder, perfect for the experimenter. I also have a page on them here.
At some point I will add more here showing how these things work.