Rockwell Automation 20-COMM-P Profibus Adapter - Manual (Page 72)

6-2 Using Explicit Messaging (Parameter Protocol)
To be able to use the parameter protocols in the 20-COMM-P, the
Parameter Access module in the GSD file must be added to the master
configuration when configuring the network. Refer to step #21,
Page 4-13 to view the procedure for adding the “Parameter Access”
module to a configuration. This maps 4 words input and output to the
end of the I/O configuration, which is used as the request/response in the
parameter message format (
Figure 6.2 ).
Parameter 23 - [Parameter Mode] in the 20-COMM-P module is used
to configure the parameter protocol that is active. The default protocol is
the Parameter Protocol.
There are five basic events in the Explicit Messaging process defined
below. The details of each step will vary depending on the controller.
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 a data.
Figure 6.1 Explicit Message Process
Running Explicit Messages
➊
➍
➎
Retrieve Parameter
Message Response
Complete Parameter
Message
Set up and send
Parameter Message
PWR STS
PORT MOD NET A NET B
➋
➌
20COMM-UM006A-EN-P.book Page 2 Friday, September 28, 2001 10:43 AM