Computer Accessories User Manual

Table Of Contents

Begin to Use the

NI-CAN Software

This chapter helps you get started with 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-CAN provides two different levels of

access to 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 Interface Object 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 (for example, two PXI-8461 two-port interfaces would provide

CAN0

through

CAN3). 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 provide higher level access to a CAN network. Each

CAN Object maps to a specific data item (arbitration ID), and you can use

multiple CAN Objects for a given port. When configuring a CAN Object

for use, you specify the arbitration ID, direction of data transfer, data

length, and how you want the data to be accessed (such as periodically).

For example, you could configure a CAN Object to transmit an outgoing

data frame for a specific arbitration ID every 100 ms. After opening this

CAN Object, you use the write function to provide data to transmit, and the

NI-CAN embedded firmware handles all periodic timing.

For detailed information about the NI-CAN software and functions, refer

to the NI-CAN User Manual and the NI-CAN Programmer Reference

Manual.