The PLC or Programmable Logic Controller

PLC Controllers are the Preferred Controllers in Factory Automation Today

Photo shows Omron Unit

The PLC or Programmable Logic Controller, is the type of control that is used, almost exclusively in today's Factory Automation applications.

We remember well, in the old days, when the only way, to control machines, was relay logic and hard wiring.

Control cabinets were huge (sometimes larger than the machine they controlled!) and if changes were required, the cost could be prohibitive.

The operator's control panel, could be a maze of push buttons and selector switches, that could be very intimidating, to the un-initiated!

The modern equivalent is the MMI -(Man/Machine Interface). In today's world, the Programmable Logic Controller is simple, reliable and cost effective. In other words, it is perfectly suited for Factory Automation.

The control unit, basically consists of a CPU (Central Processing Unit), and I/O modules (Input/Output modules). These units are generally track mounted and fully modularized, thus very adaptable to change, and very space effective.

The Input Modules are connected to switches, analog process variables (pressure, temperature, position etc.) or possibly machine-vision.

Output Modules, could be electric motors (ac or dc), or solenoids, usually controlling valves for hydraulic or pneumatic cylinders.

Programming, is accomplished, using a laptop computer, and connection to the controller is generally via a special cord, specific to the controller manufacturer.

Ladder Logic is still used and widely understood.

For manufacturers of these controllers, try these links:

Omron

Siemens

Allen-Bradley
 

Please note that the above listed companies are by no means the only manufacturers, nor the only ones we have used, over the years, but they do make an excellent product, THAT IN THE CORRECT APPLICATION, should give years of trouble free service.

To find out more about how your company can benefit from plc controllers, please feel free to contact us.

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