Rockwell Automation 2100-GK61 DeviceNet to SCANport - Manual (Page 108)

Publication 2100-UM001B-EN-P – January 2001
6-16 Using DeviceNet Explicit Messaging
3. The slave device transmits the Explicit Message Response back
to the scanner and is queued into a file transfer buffer.
4. The processor uses an M1 file transfer to retrieve the Explicit
Message Response from the scanner’s buffer (upload).
5. Format an M0 file transfer with a Delete Response Command and
the current transaction ID read in step 4. The transaction IDs are
deleted and can be reused.
The scanner module requires a precisely-formatted M0 and M1 file
transfer size of 32 words, including words 224-255. The scanner
module uses the file memory content as client/server request.
Message Translations The communications adapter provides electronic translations of
DeviceNet explicit messages into SCANport messages and back. The
format of all DeviceNet explicit messages supported by the adapter is
8:16: within an explicit message, the class field is 8 bits long, and the
instance field is 16 bits long.
Examples The following examples show messages used with the ladder logic
programs begun in Chapter 5, Ladder Logic Programming—
Including Reading Inputs.
Messaging for the 1747-SDN
Scanner The SLC copies an Explicit Message into the scanner’s M0-file.
When the copy is completed, the scanner moves the message into a
queue for processing. Up to ten Explicit Messages may be in this
queue.
When the scanner receives a response message, it is placed into a
queue. The first response in the queue is available from the M1-file.
When the message delete command is copied into the scanner, the
message is complete and the next available response will appear in
the M1-file.
!
ATTENTION: The example ladder logic program
shown in this manual is intended solely for purpose of
example. Because there are many variables and
requirements associated with any particular installation,
Rockwell Automation does not assume responsibility or
liability (to include intellectual property liability) for
actual use based upon the example shown in this
publication.