Rockwell Automation 1769-ADN Compact I/O 1769-ADN DeviceNet Adapter - Manual (Page 82)

Publication 1769-UM001B-EN-P - October 2002
4-6 Configuring Your Compact I/O Series B DeviceNet Adapter
Using Banks of I/O Configuration Rules for Series B Adapters
• The Series B adapter must be the first and left-most module in the
system (the first module of Bank 1).
• The Series B adapter can communicate with up to 30 modules in
a system.
• Each bank of I/O must have its own power supply.
• A bank of I/O can have a maximum of 16 modules with a
maximum of eight on either side of the power supply, depending
upon module loading on the supply.
• A 1769 I/O power supply has limits in the amount of +5V dc and
+24V dc current it can supply to the modules in its I/O bank.
These limits depend on the catalog number (e.g. 1769-PA2) of the
supply. A bank of modules should not exceed the current limits
of the I/O bank power supply. Refer to the Compact 1769
Expansion I/O Power Supplies Installation Instructions,
publication 1769-5.14.
• The maximum amount of current each bank supports in one
direction (either side of the power supply) is: 2A @ 5V dc, 1A @
24V dc.
• If another bank of I/O is required, use a bus communication
expansion cable (e.g. 1769-CRL) to link them together. You can
have a maximum of three banks of I/O connected with up to two
communication expansion cables.
• Each module type has its own distance rating (the number of
modules from the power supply). Each module must be within
this rating for its type.
• The Series B adapter has a distance rating of five, therefore the
adapter must be within five modules of the power supply.
• The Series B adapter supports reading a maximum of 163-251
words (326-502 bytes) of input data distributed across all the
modules, depending on the number of modules present in the
system.
Use the following equation to calculate the maximum number of
input words:
Maximum Input Words = 256 - [(Number of Modules +1) x 2 +
Number of Output Only Modules + 1]
Where the "Number of Modules" is the total number of modules
(input and output) in the system, and the "Number of Output
Only Modules" is the number of output modules configured to
have 0 words of input data.
The maximum number of input words is distributed across all of
the input modules.