What type of BIT is conducted any time the terminal is switched from OFF or STBY to the ON state?

A Start-Up BIT, or Built-In Test, is specifically designed to be performed whenever the terminal transitions from an OFF or STBY (standby) state to an ON state. This initial check ensures that the system is functioning properly before it begins operations. The purpose of a Start-Up BIT is to verify that all necessary components are operational and that the hardware is ready for use. This is crucial in maintaining reliability and safety in operations, especially in mission-critical environments where system failures can lead to significant risks.

Operational BITs, on the other hand, are typically conducted during the operation of the system to monitor performance and detect any faults that might arise while the system is in use. Background BITs run continuously in the background without interrupting the operation of the terminal, checking for faults at regular intervals or during inactive periods. Interruptive BITs occur when a system is in operation, and a fault is detected, thereby interrupting the current operation to perform a diagnostic check.

The distinction is important: a Start-Up BIT is a preliminary check that takes place right when the system is powered on, distinguishing it from the other types of BITs which are conducted under different circumstances or during different phases of operation.