Rockwell Automation 22-COMM-D DeviceNet Adapter - Manual (Page 63)

Using Explicit Messaging 6-7
There are five basic events in the Explicit Messaging process. The details
of each step will vary depending on the controller (ControlLogix, PLC,
or SLC). Refer to the documentation for your controller.
Important: There must be a request message and an response message
for all Explicit Messages, whether you are reading or
writing data.
Figure 6.4 Explicit Message Process
1. You format the required data and set up the ladder logic program 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. The data is stored in the scanner buffer.
4. The controller retrieves the Explicit Message Response from the
scanner’s buffer (upload).
5. The Explicit Message is complete. If you are using a PLC or SLC,
delete the transaction ID so that it can be reused.
Running Explicit Messages
➊
➋
➌
➍
➎
Set up and send Explicit
Message Request
Retrieve Explicit
Message Response
Complete Explicit
Message