Rockwell Automation 1734-ADNX POINT I/O DeviceNet Adpater User Manual - Manual (Page 39)

Publication 1734-UM002C-EN-P - July 2003
What is the 1734-ADN(X) Adapter? 2-19
Overview of the Communication Process
In a typical configuration, the adapter acts as an interface between a
DeviceNet scanner (e.g., 1756-DNB) and POINT I/O modules. The
example graphic below shows information transferred from a
1756-DNB to POINT I/O modules.
Four data transfers are shown in the diagram, including:
1. Scanner to adapter
2. Adapter to I/O modules
3. I/O modules to adapter
4. Adapter to scanner
Because the adapter simultaneously resides on the DeviceNet network
and on PointBus, it serves as a slave to the processor (i.e., #1 & 4) and
a master to the I/O modules (i.e., #2 & 3).
The four data transfers are not necessarily sequential.
IMPORTANT
Although information is exchanged between the
Logix5550 and 1756-DNB, this diagram (nor this
chapter) is not designed to explain such an
exchange.
computer with PLC
programming software
ControlNet network
Logix5550 controller
1784-PCD
PCMCIA card
1734-ADN adapter
DeviceNet network
computer with
RSNetWorx for
DeviceNet software
POINT I/O modules
42409
The computers and PCMCIA
card shown in the diagram
are required to configure the
processor, adapter and I/O
modules.
Although the PCMCIA card
is used in this example, you
can use other
communications cards, such
as PCID and KFD cards.
Key Points About Scanner to Adapter Transfer (Step 1)
1. Scanner initiates transfer
2. Scanner uses DeviceNet I/O messaging to write
data to adapter. Data may contain:
• device output data
• configuration data
Key Points About Adapter to Output Module Transfer (Step 2)
1. Adapter initiates transfer
2. Adapter produces data for I/O module to consume.
Data may contain:
• device output data
• configuration data
Key Points About Input Module to Adapter Transfer (Step 3)
1. Adapter consumes data I/O module has produced.
Data may contain:
• device input data
• status data
Key Points About Adapter to Scanner Transfer (Step 4)
1. SDN consumes I/O data produced by adapter.
Data may contain:
• device input data
• status data
The Logix5550 controller sits in the backplane.
The 1756-DNB contained in the controller
communicates with the 1734-ADN(X).