Start-up Monitor
The start-up monitor is graphically represented by a state-device as follows:
Start-up monitor block diagram
The factory preset of the start-up monitor is the OFF state. When the software application sets the StartupTimeout element, the start-up monitor goes in the ARMED state. In the ARMED state, the start-up monitor waits for a new start-up sequence. The start-up monitor is able to memorize its state and the StartupTimeout element. In other words, its fully operational when power is applied, and before the launch of the software application.
The start-up monitor can be in three states: OFF, ARMED, or CNT DOWN.
OFF
In the OFF state, the start-up monitor is disabled.
ARMED
In the ARMED state, the start-up monitor is waiting for a start-up sequence to monitor. For example, the start-up monitor detects a new start-up sequence when power is applied (Power On), or a start-up sequence can be engaged following a PC reset relay closure generated by the application monitor.
CNT DOWN
The start-up monitor goes in the CNT DOWN state, and begins to count the time that elapses. Two situations may occur in the CNT DOWN state:
- The application is working correctly, and sets the StartupTimeout element within the time-out expiration. The start-up monitor concludes that the start-up sequence has been completed. The start-up monitor goes in the ARMED state, waits for a new start-up sequence, and the application monitor is triggered.
- The start-up is abnormally long, and the application could not set the StartupTimeout element before time-out expiration. The start-up monitor concludes that the start-up sequence has not been completed. The start-up monitor goes in the OFF state, and closes the PC reset relay for about 1 second.