Correct Answer: A) A single controller adjusts both heating and cooling valves, with the signal split into two ranges: one range controlling the heating valve and the other range controlling the cooling valve.
Explanation:
- In a split range control system, a single controller is used to manage both the heating and cooling processes. The controller's output signal is split into two distinct ranges.
- One range of the output signal operates the heating valve, while the other range operates the cooling valve.
- This approach ensures that as the jacket water temperature fluctuates, the controller can either increase heating (by opening the heating valve) or increase cooling (by opening the cooling valve), depending on the needs of the system.
- This method allows for smooth transitions between heating and cooling, maintaining the desired temperature setpoint.
Why the Other Options Are Incorrect:
B) Two separate controllers operate independently, one controlling the heating system and the other controlling the cooling system, with no interaction between them.
- This describes a dual control system, not a split range system. Split range control involves a single controller managing both heating and cooling, not two separate, independent controllers.
C) A primary controller adjusts the temperature setpoint, while a secondary controller modulates the flow of coolant based on the primary controller's output.
- This describes a cascade control system, where one controller (primary) sets the target for another (secondary). It does not describe a split range system, where one controller splits its output to control two different processes (heating and cooling).
D) A single controller controls the cooling valve, while a separate controller is responsible for monitoring temperature and making adjustments to the heating system.
- This again suggests independent control by separate controllers rather than a single controller splitting its output to manage both heating and cooling, which is the essence of a split range control system.
Correct Answer: A) A single controller adjusts both heating and cooling valves, with the signal split into two ranges: one range controlling the heating valve and the other range controlling the cooling valve.
Explanation:
- In a split range control system, a single controller is used to manage both the heating and cooling processes. The controller's output signal is split into two distinct ranges.
- One range of the output signal operates the heating valve, while the other range operates the cooling valve.
- This approach ensures that as the jacket water temperature fluctuates, the controller can either increase heating (by opening the heating valve) or increase cooling (by opening the cooling valve), depending on the needs of the system.
- This method allows for smooth transitions between heating and cooling, maintaining the desired temperature setpoint.
Why the Other Options Are Incorrect:
B) Two separate controllers operate independently, one controlling the heating system and the other controlling the cooling system, with no interaction between them.
- This describes a dual control system, not a split range system. Split range control involves a single controller managing both heating and cooling, not two separate, independent controllers.
C) A primary controller adjusts the temperature setpoint, while a secondary controller modulates the flow of coolant based on the primary controller's output.
- This describes a cascade control system, where one controller (primary) sets the target for another (secondary). It does not describe a split range system, where one controller splits its output to control two different processes (heating and cooling).
D) A single controller controls the cooling valve, while a separate controller is responsible for monitoring temperature and making adjustments to the heating system.
- This again suggests independent control by separate controllers rather than a single controller splitting its output to manage both heating and cooling, which is the essence of a split range control system.