ibconf–Interface Bus Configuration Utility
Chapter 7
NI-488.2M UM for Windows NT
7-4
© National Instruments Corp.
Bus Timing
Use this item to specify the source handshake T1 delay of the board.
This delay determines the minimum amount of time, after the data is
placed on the bus, that the board asserts the GPIB DAV line during a
write or command operation. Refer to the ANSI/IEEE Standard 488.1-
1987, Section 5.2 for more information about the factors that might
affect the choice of the T1 delay. For example, if the total length of the
GPIB cable in the system is less than 15 meters, then the value 350 ns
is appropriate. The default for this item, 500 ns, should work in all
systems.
Cable Length
This field specifies the number of meters of GPIB cable you have in
for High Speed your system. If you use the HS488 high-speed protocol to
communicate with HS488-compliant devices, you must specify the
total number of meters of GPIB cable in your system. The System
Controller, when it initializes the GPIB, must send this information to
all HS488 devices so high-speed transfers occur without errors.
OK
Use this button to keep the configuration as shown and return to the
main dialog box.
Cancel
Use this button to discard any configuration changes made to the board
and return to the main dialog box.
Help
Use this button or the <F1> key to bring up help for this dialog box.
Software
Use this button to expand the board configuration dialog box. You can
then view or modify the GPIB characteristics of the board which you
would normally configure in your application program using the
ibconfig
function.
The following configuration items appear only for certain GPIB interface boards such as
the AT-GPIB. Other boards such as the MC-GPIB are configured automatically.
Base I/O
Use this item to select the I/O address of the interface board. It must be
Address
set to the same value as the base I/O address selected with the switches
on the board. For more information about setting the base I/O address
of your board, refer to the getting started manual that came with your
GPIB interface board.
To assist you in configuring the interface board properly,
ibconf
shows a picture of the base I/O address switch of the board. You
should confirm that the switch settings on your interface board match
the picture in
ibconf
. The switch picture in
ibconf
is also an
interactive control. You can use your mouse to change the position of
the switches in the picture. When you change the position of the
switches,
ibconf
updates the number displayed in the Base I/O
Address field. Set the switch in
ibconf
to look like the switch on
your board.