Allen-Bradley PowerFlex 20-comm-c FRN 1. Series, User Manual

Page: 68 / 159

5-14 PLC-5C Applications
The ControlNet I/O Transfer (CIO) instruction is used to send Explicit
Messages. For PLC-5C controllers before Series F Revision C, the
available services you should use are Get Attribute Single, Get Attribute
All, Set Attribute Single, or Set Attribute All. Series F Revision C (or
later) allow for more complex messages using a new Generic
Bi-Directional communication command.
Figure 5.5 Explicit Messaging
A Get Attributes Scattered message allows for reading multiple
parameters that may or may not be in sequential order (
Figure 5.6 ).
•
A Service Code of “4B” indicates the Get_Attributes_Scattered
service (see
Page C-19 , Object Specific Services ).
•
A Class Number of “93” indicates accessing the DPI Parameter
Object (see
Page C-16 , DPI Parameter Object ).
•
An Instance Number of “0” accesses the Class Attributes (see
Page C-16 , Instances ).
•
N13:0-11 contains the request message and N14:0-11 contains the
response message (see
Page C-20 , Format for
Get_Attributes_Scattered Service ).
Explicit Messaging Examples
This rung sends a message to the drive over ControlNet and receives
file N13 while the response data is placed in data file N14.
the response from the drive. The message to be sent is built in data
0000
N7:2
0
User Logic
Message
Initiate
EN
DN
ER
CIO
ControlNet I/O Transfer
Control
CT12:0
Setup Screen
CIO
0001
END
20COMM-UM003A-EN-P.book Page 14 Wednesday, November 7, 2001 3:46 PM