Programmable Logic Controller:

• A Programmable Logic Controller is typically the hardware that will control the process. In case you're wondering, a PLC looks like a box filled with electrical circuits similar to your desktop computer. A PLC is typically housed in what's called an electrical enclosure in order to protect it from the harsh environments they may control.
• BASIC COMPONENTS:

A PLC is composed of a few basic parts. They might look slightly different from various manufacturers, but the purpose and scope of each component are the same. These include a power supply, a central processing unit (CPU), input/output cards, and a backplane or rack that the input/output (I/O) cards are placed into.

creates an electrical connection between all the separate components, giving the PLC its modular design. This electrical connection includes both power and communication signals. Many PLC manufacturers use proprietary communication protocols on the backplane so that I/O can securely talk to the CPU.

 Central Processing Unit (CPU)

The CPU is the actual ‘brain’ of the PLC, making it a computer. Even small, non-modular PLCs contain a CPU. Input signals come from the I/O cards, and the logic programs make decisions based on the signals. If required, the CPU then commands outputs to turn on and off as signals and conditions change.

• Programs may include advanced functions such as math operations, timing, counting, and sharing information via modern network protocols. Many of these operations were extremely difficult, if not impossible, with the older relay systems.

I/O Cards

Sensors, buttons, switches, relays, solenoids, and even networked devices share information with I/O signals connected to screw terminals on the I/O cards. These cards can be chosen based on the needs of each machine and facility. In some small plc's, the I/O terminals are not modular cards, but rather are conveniently installed right on the side of the PLC.

Due to the wide variety of I/O device construction, there are a wide variety of discrete and analog modules, with terms such as , sourcing vs sinking and ‘voltage’ vs ‘current’ for analog models. #snsinstitution #snsdesignthinkers #designthinking