Specifications

Advanced Configuration Features
96
31004624 8/2009
Configuring Mandatory Modules
Summary
As part of a custom configuration, you can assign mandatory status to any I/O
module or preferred device on an island. The mandatory designation indicates that
you consider the module or device critical to your application. If the NIM does not
detect a healthy mandatory module at its assigned address during normal
operations, the NIM stops the entire island.
NOTE: The Advantys Configuration Software is required if you want to designate an
I/O module or a preferred device as a mandatory module.
Specifying Mandatory Modules
By default, the Advantys STB I/O modules are in a non-mandatory (standard) state.
Mandatory status is enabled by clicking on the mandatory checkbox on a module or
preferred device’s Options tab. Depending on your application, any number of
modules that your island supports can be designated as mandatory modules.
Effects on Island Bus Operations
The following table describes the conditions under which mandatory modules affect
island bus operations and the NIM’s response:
Condition Response
A mandatory module is not
operating during normal island
bus operations.
The NIM stops the island bus. The island enters fallback
mode (see page 103). I/O modules and preferred
devices assume their fallback values.
You attempt to hot swap a
mandatory module.
The NIM stops the island bus. The island enters fallback
mode. I/O modules and preferred devices assume their
fallback values.
You are hot swapping a standard
I/O module that resides to the left
of a mandatory module on the
island bus, and the island loses
power.
When power is restored, the NIM attempts to address the
island modules but must stop at the empty slot where the
standard module used to reside. Because the NIM is now
unable to address the mandatory module, it generates a
mandatory mismatch condition. The island does not start
when this condition is present.