50 - Control Ladder Logic

Which of the following statements is true of NOT logic?

NOT logic requires that a single input not be activated for an output to be energized.

NOT logic can be formed by a single N.C. switch.

A common use of NOT logic is an emergency stop pushbutton.

All of the above

None of the above

D

An OR logic circuit is formed by 2 or more N.O. switches in parallel.

True

False

True

A ladder diagram arranges the conductors in straight horizontal lines, like rungs on a ladder, with only outputs on each rung.

True

False

False

Which of the following is a step in a control process?

Logic

Output

Input

All of the above

None of the above

D

NAND logic is formed by 2 or more N.O. switches in parallel.

True

False

False

When a pushbutton switch with N.O. contacts is activated, the switch will produce a(n) __________.

Open circuit

Closed circuit

Short circuit

All of the above

None of the above

B

NOR logic is formed by 2 or more N.C. switches in parallel.

True

False

False

Which of the following is a component of a ladder diagram?

Conductors

Power supply

Output devices

All of the above

None of the above

D

Which of the following statements is not true of AND logic?

All input devices on a rung must be activated.

An AND logic circuit is made of 2 or more N.O. switches in series.

In an AND logic circuit, only one of the inputs must be activated to energize the output.

All of the above

None of the above

C

Selector switches are often used to change the operating mode of a machine.

True

False

True

Which of the following is not a rule of drawing a ladder diagram?

Label all components

Each rung (line) can have more than one output device (load)

Number each rung

Show control devices only

B

Manual control systems require a pilot device to control the operation.

True

False

False - required human, trick question

The best method for reading ladder diagrams is to start at the upper left (first input on the first rung) and work your way across the rung before moving to the first input of the next rung and work across.

True

False

True

Which of the following is a use of an indicator lamp?

Indicate that the power is on.

Indicate that a cycle has begun.

Indicate that a dangerous condition is occurring.

All of the above

None of the above

D

Which of the following is one of the six elements of control logic?

NAND

OR

NOT

All of the above

None of the above

D

The series of moves a machine has to make in order to perform a task is called a(n) __________.

Sequence of operation

Control process

Automated sequence

Logical progression

A