Rockwell Automation PowerFlex 750-Series, Руководство пользователя

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6-2 Using Explicit Messaging
PowerFlex 750-Series Drive DeviceNet Option Module User Manual
Publication 750COM-UM002A-EN-P
Performing Explicit
Messages There are five basic events in the Explicit Messaging process. The
details of each step will vary depending on the type of controller being
used. Refer to the documentation for your controller.
Important: There must be a request message and a response message
for all Explicit Messages, whether you are reading or
writing data.
Figure 6.1 Explicit Message Process
For information on the maximum number of Explicit Messages that can
be executed at a time, refer to the user manual for the scanner and/or
controller that is being used.
Event Description
➊
You format the required data and set up the ladder logic program to send an
Explicit Message request to the scanner module (download).
➋
The scanner module transmits the Explicit Message Request to the slave
device over the network.
➌
The slave device transmits the Explicit Message Response back to the
scanner. The data is stored in the scanner buffer.
➍
The controller retrieves the Explicit Message Response from the scanner’s
buffer (upload).
➎
The Explicit Message is complete. Note: The scanner module may be
integrated with the controller (for example, ControlLogix).
➎
➊
➋ ➌
➍
Complete Explicit
Message
Retrieve Explicit
Message Response
Set up and send Explicit
Message Request