A status of DD indicates what condition of the site controller?

The status of DD indicating the site controller is in diagnostic mode means that the site controller is actively engaged in running internal tests or checks to assess its operational capability. In this mode, the system is typically focused on troubleshooting or evaluating the performance of its various components. This can include checking connections, verifying that the hardware is functioning correctly, and ensuring that the software is operating as intended. Hence, a DD status is specifically designed for diagnostics rather than reflecting normal performance or operational issues like power failure or connection problems.