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Chapter 2: PLC Hardware Components - Coggle Diagram
Chapter 2: PLC Hardware Components
2.1: The I/O Section
When referring to PLCs, the processor identify the location of a specific input or output device through addressing
The three basic elements of rack/slot-based addressing includes the type, slot, and word and bit
2.2: Discrete I/O Modules
When referring to discrete input modules, there are a variety of field input devices that are suitable for use with them
A couple of examples could include selector switches, pushbuttons, and limit switches.
2.3: Analog I/O Modules
There are many advantages of analog I/O modules over discrete or digital I/O interfaces
One advantage of analog I/O modules over discrete I/O is that they can handle continuous signals, allowing for more precise control of variable inputs and outputs like temperature or pressure.
2.4: Special I/O Modules
Many different types of I/O modules have been developed
to meet special needs.
One example includes the development of the stepper motor module, which provides pulse trains to a stepper-motor translator
2.5: I/O Specifications
There are specific I/O module specifications that manufacturers provide based on the needs of the company
One example of a specific I/O module specification would be the ambient temperature rating
2.7: Memory Design
There are two different ways you can analyze or edit data.
Data is stored in a memory location by a process called writing. Data is retrieved from memory, which is called reading
2.8: Memory Types
The memory of a PLC may be broken into sections that
have specific functions.
These specific types include Read-Only Memory, Random Access Memory, Erasable Programmable Read-Only Memory, and others as well
2.10: Recording and Retrieving Data
One downside of a PLC is that it can have only one program in memory at a time.
One solution to this would either be to enter a new program directly from the keyboard or to download one from the computer hard
drive
2.9: Programming Terminal Devices
There are three typical purposes for programming terminal devices
These three purposes include entering, modifying, or troubleshooting the PLC program. This can be done through a hand-help programming terminal or a personal computer.
2.11: Human Machine Interfaces
Human machine interfaces give the ability to the operator
and to management to view the operation in real time. Through the use of personal computers, you can configure display screens to do many things.
One of the things you can do is to show operations in graphic format for easier viewing. Also, you can configure the PLC to show alarms, complete with time of occurrence and location.
2.6: The Central Processing Unit
There is a couple of major functions for the CPU of a PLC. Without this component, the PLC could not perform properly.
One purpose is to process the control logic by executing programmed instructions and managing data exchange between input/output devices and other system components.