Chapter 1 NI-DNET Software Overview
© National Instruments Corporation 1-7 NI-DNET User Manual
Figure 1-2. NI-DNET Objects for a Network of Three Devices
Using NI-CAN with NI-DNET
Controller Area Network (CAN) is the low-level protocol used for
DeviceNet communications. In addition to the NI-DNET functions, your
National Instruments DeviceNet hardware can also be used for low-level
access to CAN messages using the NI-CAN software. NI-CAN is intended
primarily for applications that require direct access to CAN messages, such
as test applications for automotive (non-DeviceNet) networks. When
connecting to a DeviceNet network, the NI-CAN capabilities are useful for
the following applications:
• Low-level monitoring of CAN messages to determine conformance to
DeviceNet specifications
• Implementation of sections of the DeviceNet Specification yourself,
such as custom configuration tools
NI-CAN uses the same software infrastructure as NI-DNET, so both APIs
can be used with the same CAN card. The general rule is that each CAN
card can only be used for one API at a time.
Use of NI-DNET is restricted to port 1 (top port) of Series 1 CAN cards.
For more information on hardware provided in CAN kits, refer to
Chapter2, N I-DNET Hardware Overview.
You can view each CAN card in MAX with either DeviceNet or CAN
features. To change the view of a CAN card in MAX, right-click the card
and select Protocol. In this dialog you can select either DeviceNet for
Your National Instruments
DeviceNet Interface
Interface Object
Interface MAC ID = 1
Baud Rate = 500K
Access to device at
MAC ID 5
I/O Object
Device MAC ID = 5
Connection Type = COS
I/O Object
Device MAC ID = 5
Connection Type = Poll
Access to device at
MAC ID 8
Explicit Messaging
Object
Device MAC ID = 8
I/O Object
Device MAC ID = 8
Connection Type = Strobe