Once the system detects a fault, sensor damage, or communication interruption in the primary Master drive (Address 1), the Standby Master drive will automatically escalate from the "auxiliary drive role" to the "master drive role" after a preset delay (e.g., 5.0 seconds set by U3-07). At this time, it no longer follows the instructions of Address 1 but becomes the supreme commander of the entire pump group system.

• Hardware Support: The system requires the Standby Master drive to be independently equipped with a pressure sensor.
• Control Logic: After takeover, the Standby Master drive will enable its own connected sensor signal to detect pipe network pressure in real time and perform PID calculation independently. It no longer relies on any data feedback from the original Master drive.

• Start/Stop Control: Automatically instruct other auxiliary drives to run or stop according to water pressure fluctuations.
• PID Synchronization: Send PID feedback information and commands to all auxiliary drives via the RS485 bus.
• Pump Adding/Reducing Logic: Fully take over the logical judgment of pump adding delay (U3-05) and pump reducing delay (U3-06).

According to technical documentation, the Standby Master drive will continue to operate as the master drive until the fault of the original Master drive is resolved and it is powered on again to resume work. This design ensures that the water supply system can maintain the continuity of constant pressure water supply even in unattended situations when core equipment fails.