Control Systems

Question 1

What is the difference between open loop and closed loop systems?

Answer 1

Closed loop system sends feedback to the controller

Question 2

When does the controlled device change position/move/rotate/activate with floating control?

Answer 2

Control point moves out of the deadband

Question 3

What is proportional band?

Answer 3

The amount of change in input for a system for which there is no reaction in the output to change from 0% to 100%

Question 4

What is throttling range?

Answer 4

The amount of change in the process variable that is necessary to cause the controller output from 0% to 100%

Question 5

_______ is the sustained deviation of the process variable from the set point?

Answer 5

Offset

Question 6

______ controller corrects for any offset between set point and the variable automatically?

Answer 6

Proportional and integral

Question 7

______ controller generates the control output proportional to the error?

Answer 7

Proportional

Question 8

______ controller limits the output to prevent the process value from overshooting the set point ?

Answer 8

Proportional, integral and derivative - PID

Question 9

Rate these fuses ranges 15 to 30amp? Is ____
Low to 60 is ______?
Over 60p is ______?

Answer 9

Knife 15 to 30
Plug low to 60
Cartridge 60 and over

Question 10

How many conductors are required for a digital 2H and 1C thermostat

Answer 10

Six wires

Question 11

How many conductors are typically required for a communicating control system on residential heat pump system?

Answer 11

Air handler to thermostat (4) and air handler to outdoor (2)

6 in total

Question 12

Where do you bond/ground the shield of a sensor communication cable?

Answer 12

At the equipment ground

Question 13

What are 5 controlled variables?

Answer 13

Temperature
Pressure
Humidity
Flow
Level