Rockwell Automation 1738-AENT, Series B ArmorPOINT I/O Dual Port EtherNet/IP Adapters User Manual - Manual (Page 14)

4 Rockwell Automation Publication 1738-UM005A-EN-P - July 2013
Chapter 1 Overview of the 1738 ArmorPOINT I/O EtherNet/IP Adapter
Important Adapter
Considerations Before you begin using your adapter, note the following important
considerations.
Set the Chassis Size
The ArmorPOINT I/O adapters require configuration of their chassis size before
you can make any I/O connections. The factory default setting for the chassis size
is one slot, which represents the adapter by itself.
You must set the chassis size to a number equaling one slot for the adapter plus
one slot for each I/O module present in the backplane of the adapter.
For example, an ArmorPOINT I/O system consisting of a 1738-AENT adapter,
one 1738-IB8, one 1738-OB8, and one 1738-OB8S POINTGuard I/O module
uses a chassis size of 4. The adapter stores this chassis size setting in non-volatile
memory.
Each time the adapter is powered up, the adapter compares the number of I/O
modules present on its backplane to the chassis size value from non-volatile
memory. The adapter does not allow any I/O connection until the number of
I/O modules present equals the chassis size value minus one for the adapter itself.
Adapter Replacement
Note that during a connection request from the controller, the chassis size setting
is not communicated to the adapter. You must always set this chassis size using a
separate operation. This includes situations when you are replacing an adapter.
The adapter does not allow any I/O connections until it is configured with the
appropriate chassis size and the proper number of ArmorPOINT I/O modules
are present.
Empty Slots and RIUP Situations
The ArmorPOINT I/O system cannot detect an empty terminal base. For this
reason, there are numerous situations in which you can potentially configure a
system that is unusable or one that exercises unintended control.
In an attempt to address these situations, you must observe the following rules for
I/O system construction and the
removal and reinsertion of modules.
• A correct I/O system does not have any empty terminal bases.
• After you cycle power, the adapter will not allow any I/O connections
until the number of modules comprising the chassis plus one for the
adapter equals
the stored chassis size.