PLC

Question 1

List the 5 main components of a PLC

Answer 1

Power supply
Input interface
Central Processing unit
Memory
Output interface

Question 2

What’s the function of an operator interface on a PLC?

Answer 2

Provides two way communication between the operator and the PLC

Question 3

Types of input/output modules for a PLC

Answer 3

• limit switch’s
• pressure switch’s
• push buttons
• motor contactors
• solenoids

Question 4

5 principles of operation for a PLC

Answer 4

• power supply
• input module
• Central Processing unit (CPU)
• memory
• output module

Question 5

Types of operator interfaces

Answer 5

• Personal computer
• Hand operated programmer
• Human machine interface

Question 6

3 processes of PLC scan cycle

Answer 6

• 1: Read
• 2: executes
• 3: writes
• 3-20 milliseconds for scan cycle to be completed