What is programmable logic controller?

1.1 Introduction The first Programmable Logic Controller (PLC) was developed by a group of engineers at General Motors in 1968, when the company were looking for an alternative to replace complex relay control systems.

How many programmable logic controllers are there in Chapter 121?

Chapter 121 C 2 C 3 B 4 B 5 A 6 A 282Programmable Logic Controllers 10 Similar to (a) Figure 12.5, (b) Figure 12.6. Chapter 131 B 2 C 3 B 4 C 5 A 6 A

How do the 198 programmable logic controllers move?

For the rung shown, when there is an input to | | in the rung, the 198 Programmable Logic Controllers move occurs from the designated source address to the designated destination address.

How does a timer work on a 160 160 programmable logic controller?

160Programmable Logic Controllers 9.2.1 Sequencing As an illustration of the use of a timer, consider the ladder diagram shown in Figure 9.5(a). When the input In 1 is on, the output Out 1 is switched on. The contacts associated with this output then start the timer.

A programmable logic controller, or PLC, is a simple electronic device that allows precise numerical control of machinery. It is widely used to control everything from washing machines to roller coaster to automated manufacturing equipment. ^ “A short history of Automation growth”.

What is a PLC controller?

Central heating system with PLC controller The programmable logic controller dates as far back as 1968 when General Motors set out to find a new technology to replace their hard-wired electromechanical relay system with an electronic device.

What type of rungs does the Allen-Bradley PLC-5 use?

The Allen-Bradley PLC-5 uses latch and unlatch rungs. If the relay is latched, it remains latched if 136 Programmable Logic Controllers M Figure 7.7Retentive memory coil