Schneider Electric 890USE17700 manual Configuring Mandatory Modules

Advanced Configuration Features

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	By default, the Advantys STB I/O modules are in a non-mandatory (standard) state.
Mandatory	Mandatory status is enabled by clicking on the mandatory checkbox on a module or
Modules	preferred device’s parameters property sheet. Depending on your application, any
	number of modules that your island will support can be designated as mandatory
	modules.

Effects on Island The following table describes the conditions under which mandatory modules affect Bus Operations island bus operations and the NIM’s response:

Condition	Response
A mandatory module fails during	The NIM stops the island bus. The island enters fallback
normal island bus operations.	mode (See Island Fallback Scenarios, p. 161). I/O
	modules and preferred devices assume their fallback
	values.
You attempt to hot swap a	The NIM stops the island bus. The island enters fallback
mandatory module.	mode. I/O modules and preferred devices assume their
	fallback values.
You are hot swapping a standard	When power is restored, the NIM attempts to address the
I/O module that resides to the left	island modules but must stop at the empty slot where the
of a mandatory module on the	standard module used to reside. Because the NIM is now
island bus, and the island loses	unable to address the mandatory module, it generates a
power.	mandatory mismatch error and the island fails to restart.

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