If an I/O module is removed in the middle of an island, all the remaining modules function properly.
However, when the island is power cycled then only the modules to the left of the missing module run properly. All the modules to the right do not run. If the missing module is re-inserted, all the modules begin functioning properly again. This occurs due to the fact that if a module is removed, on a power cycle the auto configuration and addressing cannot be completed (auto addressing line open on bus) causing the module to be not detected.
This explanation is described in the Advantys STB System Planning and Installation Guide (890USE17100), in the section titled "Commissioning an Advantys STB Island".
Legacy KB System (APS) Data: RESL172633 V1.0, Originally authored by on , Last Edited by on
Related ranges: Advantys STB