Chapter 1
Introduction
© National Instruments Corp.
1-5
NI-488.2M UM for Windows NT
Controlling More Than One Board
The NI-488.2M driver can control up to 10 GPIB boards. Figure 1-3 shows an example
of a multiboard system configuration.
gpib0
is the access board for the voltmeter, and
gpib1
is the access board for the plotter and printer. The control functions of the
devices automatically access their respective boards.
Printer
Plotter
Digital Voltmeter
gpib0
gpib1
One
GPIB
Another
GPIB
Figure 1-3. Example of Multiboard System Setup
Configuration Requirements
To achieve the high data transfer rate that the GPIB was designed for, you must limit the
physical distance between devices and the number of devices on the bus. The following
restrictions are typical:
•
A maximum separation of four meters between any two devices and an average
separation of two meters over the entire bus.
•
A maximum total cable length of 20 m.
•
A maximum of 15 devices connected to each bus, with at least two-thirds powered
on.