Posts Tagged ‘systems’
Timer, Counters and Relays
Relays:
A relay is an electrical switch that opens and closes under the control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts.
A simple relay has 5 pins. The left 2 pins are the operating part by taking input, the rest of the pins are the switching part to get output. A 4 pin relay doesn’t have NC pin. Read the rest of this entry »
Non-functional Requirements
Non functional requirements can be defined as follows:-
- In systems engineering and requirements engineering, non-functional requirements are requirements that specify criteria that can be used to judge the operation of a system, rather than specific behaviors.
- It defines the overall qualities or attributes of the resulting system.
- It places restrictions on the product being developed, the development process, and specify external constraints that the product must meet.
“A non-functional requirement is a statement of how a system must behave, it is a constraint upon the systems behavior.” Read the rest of this entry »
Introduction to PLC
Programmable Logic Controller
Control engineering has evolved over time. In the past humans were the main method for controlling a system. More recently electricity has been used for control and early electrical control was based on relays. These relays allow power to be switched on and off without a mechanical switch.It is common to use relays to make simple logical control decisions. The development of low cost computer has brought the most recent revolution, the Programmable Logic Controller (PLC). The advent of the PLC began in the 1970s, and has become the most common choice for manufacturing controls.
Advantages
- Cost effective for controlling complex systems.
- Flexible and can be reapplied to control other systems quickly and easily. Read the rest of this entry »