Rockwell Automation 1769-SDN Compact I/O DeviceNet Scanner Module User Manual - Manual (Page 47)

Publication 1769-UM009E-EN-P - August 2009 47
Automatically Configure a DeviceNet Network Chapter 4
2. Set up I/O allocation size in the scanner.
The default AutoScan setting allocates a 4-byte entry in both the input
and output memory maps in the scanner for each slave device detected
on the network. This default size is chosen to accommodate the default
Logix native data size of 32 bits (DINT). If that is adequate for the
application, skip to
step 3 .
For applications where the user would like to customize the I/O
allocation size, the 4-byte allocation could be adjusted through an
Explicit Message to the scanner using the SetAttributeSingle service.
The entry allocation could be configured for 1 to 32 bytes per node.
One way to set the allocation size is described in section
Configure I/O
Allocation Size Via the User Program.
The following table lists devices that most commonly use the
AutoScan feature and their respective I/O allocation sizes.
TIP
This step is optional.
Device Bulletin Number Input Allocation Output
Allocation
ArmorStart Distributed
Motor Controller 280D/281D 1 byte 1 byte
193-E Electronic
Overload Relays 193 8 bytes 1 byte
PowerFlex 40
Adjustable Frequency
AC Drive 22B 4 bytes 4 bytes