Which statement best describes a master reset's effect on control logic?

Which statement best describes a master reset's effect on control logic?

• A. Resets the last operated device
• B. Resets only the PLC memory
• C. Resets all control logic to the initial state
• D. Resets read-only memory

Answer: (C)

Master reset reinitializes the control system so everything starts from its defined starting condition. It clears all active states in the control logic—such as state machines, timers, counters, and latches—so the program can begin again from its initial execution point. The outputs are driven to their default states as dictated by the control logic when it’s reset. It isn’t about resetting just the last device, nor is it about resetting only PLC memory or ROM, since ROM is read-only and cannot be changed by a reset. In practice, a master reset mainly clears the active control-state data in RAM and returns the logic to its initial state.

Master reset reinitializes the control system so everything starts from its defined starting condition. It clears all active states in the control logic—such as state machines, timers, counters, and latches—so the program can begin again from its initial execution point. The outputs are driven to their default states as dictated by the control logic when it’s reset. It isn’t about resetting just the last device, nor is it about resetting only PLC memory or ROM, since ROM is read-only and cannot be changed by a reset. In practice, a master reset mainly clears the active control-state data in RAM and returns the logic to its initial state.