Automation Exam Review

Question 1

Which industry first used programable logic controllers ?

Answer 1

Automotive industry

Question 2

A PLC is a special kind of _________?

Answer 2

Industrial computer

Question 3

List 4 major components of a PLC

Answer 3

1. power supply
2. Central processing unit (CPU)
3. Programming terminal
4. I/O (Input/Output)

Question 4

In a PLC, all logic functions are performed by the _______?

Answer 4

CPU

Question 5

A plc power supply must be able to regulate voltage within what %

Answer 5

5% of the required value

Question 6

Another name for the programming terminal is the ____________ terminal?

Answer 6

Loading

Question 7

Are NEMA symbols such as push buttons, limit switches or selector switches used in a PLC ladder diagram?

Answer 7

No. Only N/O and N/C symbols are used.

Question 8

How are contacts of a PLC identified ?

Answer 8

By a number. ( contacts address)

Question 9

In a ladder diagram, each rung ends with a ______?

Answer 9

Coil

Question 10

What part of the PLC is referred to as the “Brains” of the PLC

Answer 10

CPU

Question 11

What type of isolation is generally used to electrically separate outside voltages from the internal circuitry of the PLC??

Answer 11

Optical

Question 12

What is connected across the AC input to help eliminate any voltage spikes that may occur on the line

Answer 12

metal oxide varistor (MOV)

Question 13

What parts of a PLC connects the CPU to the real world input/output devices?

Answer 13

The Input/output modules

Question 14

In a PLC timers and counters are what?

Answer 14

-computer generated
-internal relays

Question 15

Push buttons, Limit switches and float switches would be considered?

Answer 15

Input devices

Question 16

The amount of current output modules can handle is generally ?

Answer 16

.5 - 3.0 amperes

Question 17

With a PLC, an internal relay is a ?

Answer 17

Computer generated device

Question 18

A numbering system that contains digits 0 through 7 is called ?

Answer 18

Octal

Question 19

A plc recognizes internal relay and timer contacts by what?

Answer 19

The contacts address

Question 20

What are the 5 basic logic gates ?

Answer 20

1.AND
2. OR
3. NAND
4. NOR
5. INVERTER

Question 21

True or False : With an AND GATE, if all inputs are high the output is High ?

Answer 21

True

Question 22

T or F : With a OR GATE if one input is high, the output is high ?

Answer 22

True

Question 23

With a NOR GATE if one is high, the output is low ?

Answer 23

Yes

Question 24

With a NAND gate, if all inputs are high, the output is low ?

Answer 24

Yes

Question 25

A logic gate in which the output is always opposite the input is the ________?

Answer 25

Inverter

Question 26

What symbol is used to represent “invert” when NEMA logic symbols are used?

Answer 26

X

Question 27

If and inverter is connected to the output of an AND gate, what logic gate is formed ?

Answer 27

NAND

Question 28

If an INVERTER is connected to the output of an OR gate, what logic gate is formed ?

Answer 28

NOR

Question 29

Which gate is referred to as a basic gate ?

Answer 29

NAND