Interface object, Explicit messaging object, Interface object -5 explicit messaging object -5 – National Instruments NI-DNET User Manual
Page 14
Chapter 1
NI-DNET Software Overview
© National Instruments Corporation
1-5
Much like any other object-oriented system, NI-DNET device driver
objects use the concepts of class, instance, attribute, and service to describe
their features. The NI-DNET device driver software provides three classes
of objects: Interface Objects, Explicit Messaging Objects, and I/O Objects.
You can open an instance of an NI-DNET object using one of the three
open functions (
ncOpenDnetExplMsg
,
ncOpenDnetIntf
, or
ncOpenDnetIO
). The services for an NI-DNET object are accomplished
using the NI-DNET functions, which can be called directly from your
programming environment (such as Microsoft C/C++ or LabVIEW). The
essential attributes of an NI-DNET object are initialized using its open
function; you can access other attributes using
ncGetDriverAttr
or
ncSetDriverAttr
. The attributes of NI-DNET device driver objects are
called
driver attributes
, to differentiate them from actual attributes in
remote DeviceNet devices.
For complete information on each NI-DNET object, including its driver
attributes and supported functions (services), refer to your NI-DNET
Programmer Reference Manual.
Interface Object
The Interface Object represents a DeviceNet interface (physical DeviceNet
port on your DeviceNet board). Since this interface acts as a device on the
DeviceNet network much like any other device, it is configured with its
own MAC ID and baud rate.
Use the Interface Object to do the following:
•
Configure NI-DNET settings that apply to the entire interface
•
Start and stop communication for all NI-DNET objects associated with
the interface
Explicit Messaging Object
The Explicit Messaging Object represents an explicit messaging
connection to a remote DeviceNet device (physical device attached to your
interface by a DeviceNet cable). Since only one explicit messaging
connection is created for a given device, the Explicit Messaging Object is
also used for features that apply to the device as a whole.
Use the Explicit Messaging Object to do the following:
•
Execute the DeviceNet Get Attribute Single service on the remote
device (
ncGetDnetAttribute
)