©NationalInstruments Corporation 4-1 PXI-846xand NI-CAN for Windows NT
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BegintoUsetheNI-CAN Software
This chapter helps you get startedw ith the NI-CAN software for
Windows NT.

Using the NI-CAN Software

The functions provided by the NI-CAN software are similar to those
provided by many other device drivers. For example, NI-CAN has open,
close,read, and write functions.NI-CA N provides two different levels of
accessto a CAN network: the CAN Network Interface Object and CAN
Objects.Both forms of access support timestamping of incoming data and
various forms of queuing.
The CAN Network InterfaceObject provides low-level access to a CAN
network.Each CAN Network Interface Object maps to a specific CAN
port,with no limitation on the maximum number of ports or boards you can
use (forexample, two PXI-8461 two-port interfaces would provide CAN0
throughCAN3). You can use this object to transmit and receive entire CAN
frames.For example, to transmit a CAN frame, you would specify the
outgoing arbitration ID, frame type (data or remote), data length, and data.
The CAN Objects providehigher levelaccess to a CAN network. Each
CANObject maps to a specific data item (arbitration ID), and you can use
multiple CAN Objects for ag ivenport. When configuring a CAN Object
for use, you specify the arbitration ID, direction of data transfer, data
length, and howyou want the data to be accessed (such as periodically).
Forexample, you could configure a CAN Object to transmit an outgoing
data frame for a specificarbitration ID every 100 ms. After opening this
CANObject, you use the write function to provide data to transmit, and t he
NI-CAN embedded firmwarehandles all periodic timing.
Fordetailed information about th eN I-CAN softwareand function s, refer
to the NI-CAN User Manual and the NI-CAN Programmer Reference
Manual.