Information regarding I/O Scanner reads when STB islands are in TEST mode.



Goals and Symptoms

This resolution has information for STB users that applies when an STBNIP2212 NIM interfaced island is operating in TEST mode.

Causes and Fixes

When IO scanner functionality is being used in the PLC to enable reading of island module inputs and diagnostic data, it is recommended to have the input and output areas on separate lines within the IO scanner. Otherwise, if the island is in TEST mode, the scanner will indicate an error and inputs will not be read. This is due to the nature of I/O Scanner operation when writes are prohibited by the island. It also applies to reading the HMI to PLC area.