Chapter+6+-+Developing+Fundamental+PLC+Wiring+Diagrams+and+Ladder+Logic+Programs

What is a PLC designed to replace?

Control relays that made logic decisions.

What type of switch is used in electromagnetic control relays?

A magnetic switch which uses electromagnetism.

What do normally open (NO) contacts do when the coil is de-energized?

They are open.

What is the purpose of a contactor?

It is designed to handle heavy power loads beyond the capability of control relays.

What device converts an electrical signal into mechanical movement?

An actuator.

What is a seal-in circuit?

A method of maintaining current flow after a momentary switch has been pressed and released.

What do proximity sensors detect?

The presence of an object without physical contact.

What principle do inductive proximity sensors work on?

They detect both ferrous and nonferrous metals using an electromagnetic field.

What distinguishes a servo motor from a stepper motor in operation?

A servo motor operates in a closed-loop mode, while a stepper motor operates in an open-loop mode.

What is the function of a thermocouple?

To generate a predictable DC voltage when two dissimilar metals are joined.

What is the role of a photoelectric sensor?

To detect a change in light intensity by responding to a visible or invisible beam of light.

What are dip switches used for?

To set the parameters for a particular module using binary (on/off) settings.

What type of circuit maintains an already finished operation state after it is triggered?

Latching circuits.