Describe the basic functions and design of PLCs.

Description should include

• central processing unit (CPU)
• digital input (DI) modules
• digital output (DO) modules
• analog input (AI) modules
• analog output (AO) modules
• extension modules
• power supply.

Process/Skill Questions:

• How does the PLC store and process signals?
• How does the PLC receive and transmit information to transducers (e.g., sensors, actuators)?
• What is the main difference between analog and discrete signals?