Rockwell Automation 2755-SNx Adaptascan Bar Code Readers - Manual (Page 187)

10–25 Communicating with an SLC 5/03 Processor on a DeviceNet Network using Explicit Messaging
Publication 2755-6.8
Explicit Message Program Control Feature
DeviceNet
drop line
DeviceNet trunk line
Master’s Explicit
Request
Slave’s Explicit
Response
1203-GK5
Communication
Adapter
MC0 file transfer (including words 224-255)
(sent from processor to scanner module)
MC1file transfer (including words 224-255)
(sent from scanner module to processor)
Explicit Message – A message used to transmit
commands, data, requests for data or
responses. The message is sent from a client
on the DeviceNet network to a server on that
network.
Request – An explicit message sent by a client
to a server requesting the server to perform
a function.
Response – An explicit message sent by a
server to a client in response to the client’s
request. For every request issued, there is a
response.
4
1305 AC
drive
5
MC1 file transfer
is completed. TXID’s
are deleted and can be
reused.
AdaptaScan
Bar Code
Reader
1. Format an M0 file transfer in the processor to send an Explicit
Message Request to the scanner module (download).
2. The scanner module transmits the Explicit Message Request to
the slave device over the DeviceNet network.
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.