Rockwell Automation 20-750-CNETC PowerFlex Coaxial ControlNet Option Module - Manual (Page 77)

Rockwell Automation Publication 750COM-UM003B-EN-P - November 2012 77
Using Explicit Messaging Chapter 6
ControlLogix – Formatting a Message to Read a Single Parameter
Figure 20 - Get Attribute Single Message Configuration Dialog Boxes
The following table identifies the data that is required in each box to configure a
message to read a single parameter.
Configuration Tab Example Value Description
Message Type
Service Type
(1)
Service Code
(1)
Class
Instance
(2)
Attribute
Source Element
Source Length
Destination
CIP Generic
Get Attribute Single
e (Hex.)
93 or 9F (Hex.)
(4)
7 (Dec.)
9 (Hex.)
—
0 bytes
Output_Current
(5)
Used to access the DPI Parameter Object in the option module.
This service is used to read a parameter value.
Code for the requested service.
Class ID for the DPI Parameter Object.
Instance number is the same as parameter number.
Attribute number for the Parameter Value attribute.
Leave blank (not applicable).
Number of bytes of service data to be sent in the message.
The tag where the data that is read is stored.
Communication Tab Example Value Description
Path
(3)
My_PowerFlex_755_Drive The path is the route that the message will follow.
Tag Tab Example Value Description
Name Single_Read_Message The name for the message.
(1) The default setting for Service Type is ‘Custom’, enabling entry of a Service Code not available from the Service Type pull-down menu. When choosing a
Service Type other than ‘Custom’ from the pull-down menu, an appropriate Hex. value is automatically assigned to the Service Code box which is
dimmed (unavailable).
(2) The instance is the parameter number in the drive (Port 0). For example, to read parameter 4 of a peripheral in Port 5 of a PowerFlex 755 drive, the
instance would be 21504 + 4 = 21508. See DPI Parameter Object on page 115 (Class code 0x93) or Host DPI Parameter Object on page 129 (Class code
0x9F) to determine the instance number.
(3) Click Browse to find the path, or type in the name of the device listed in the I/O Configuration folder (for this example, My_PowerFlex_755_Drive).
(4) See
Table 4 on page 74 for limitations of PowerFlex 750-Series drives when using DPI Parameter Object Class code 0x93 or Host DPI Parameter Object
Class code 0x9F for explicit messaging.
(5) In this example, Output Current is a 32-bit REAL (floating point) parameter requiring the Data Type field to be set to ‘REAL’ when creating the controller
tag. To read a 32-bit integer parameter, set the tag Data Type field to ‘DINT’. For a 16-bit parameter, set the Data Type field to ‘INT’. See the drive
documentation to determine the size of the parameter and its data type.