Allen-Bradley Compact I/O 1769-ADN DeviceNet, User Manual

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Publication 1769-UM001B-EN-P - October 2002
Explicit Messaging Application Examples B-15
1747-SDN Explicit
Messaging Application
Example
The following explicit messaging application example details a
1747-SDN DeviceNet scanner controlling 1769 Compact I/O via
DeviceNet and the 1769-ADN DeviceNet Adapter.
While explicit messages are not required when using 1769 I/O on
DeviceNet, these messages allow you to read status information from
the 1769-ADN adapter and 1769 I/O modules as well as write 1769
I/O module configuration parameters while the system is running.
These operations are not required when using the 1769-ADN adapter,
but may be necessary from an application view if, for example, you
need to modify the configuration of an I/O module while the system
is running. Also, in the event of failure, you may need to read status
information from the 1769-ADN or I/O module from a remote
terminal.
Before attempting any explicit messages to a 1769-ADN, the adapter
must be configured in a DeviceNet scanner’s scanlist. This example
uses a 1747-SDN DeviceNet scanner in slot 3 of a SLC-5/04 processor
chassis. RSLogix 500 programming software is used to program the
SLC-5/04 processor.
We’ll cover the following list of message commands in this example:
•
Get 1769-ADN Status
•
Get 1769 I/O Module Status
•
Get 1769 I/O Module Configuration File Size
•
Set 1769 I/O Module Configuration
•
Save 1769 I/O Module Configuration
•
Get 1769 I/O Module Configuration
Get 1769-ADN Status
The Get 1769-ADN Status command has 6 words, where the first three
are required by the 1747-SDN scanner and the last three are sent to
the 1769-ADN. As you will see in the sample ladder logic below, a
command is sent to the 1747-SDN via a COPy instruction to the
scanner’s M0 file. The reply is then received in the scanner’s M1 file.
The user program is notified that the command reply is ready when
the scanner sets an input image bit (I:s/15, where s is the slot number
of the 1747-SDN). When this bit is set, the user program COPies the
reply from the scanner’s M1 file.
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