Справочник Пользователя для National Instruments NI-DNET
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 (
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
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.
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.
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
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.
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 (
device (
ncGetDnetAttribute
)