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EtherNet/IP – Communication profiles 161
ODVA AC/DC drive profile
This section briefly describes the ODVA AC/DC drive profile.
Additional information is available at www.odva.org .
An EtherNet/IP node is modeled as a collection of abstract objects.
Each object represents the interface to and behavior of a
component within the product. The ODVA AC/DC drive profile
defines a collection of objects suitable for the control of AC and DC
drives. The objects supported by the adapter module are listed in
section Class objects on page 217 .
Objects are defined by:
•
Service
•
Class
•
Instance
•
Attribute
•
Behavior.
For example, to set the drive speed reference, the
Set_Attribute_Single service can be requested for the SpeedRef
attribute of the AC/DC drive object class. The resulting behavior is
that the reference speed of the drive is set to the requested value.
This is an example of explicit messaging,
where each attribute of a
class is set individually. While this is allowed, it is inefficient.
Instead, implicit messaging using input and output assembly
Instances is recommended. Implicit messaging allows the
EtherNet/IP client to set or get predefined groups of attributes in a
single message exchange. The assembly instances supported by
the adapter module are listed and defined in section Assembly
objects on page 182 .