National Instruments GPIB-PC User Manual
Page 88
Section Four A
BASICA/QuickBASIC GPIB-PC Function Calls
©National Instruments Corp.
4A-13
GPIB-PC User Manual
There are a few differences between the existing subroutines and the
new functions:
•
ILFIND
returns a descriptor associated with the specified device.
Use this value in all subsequent functions calls that access that
device. Normal usage would resemble the following:
BD% = ILFIND ("GPIB0")
•
ILCMD
,
ILCMDA
,
ILRD
,
ILRDA
, and
ILWRTA
require a third
parameter which specifies the number of bytes to transfer. The
function syntax is as follows:
ILCMD (BD%, CMD$, CNT%)
ILCMDA (BD%, CMD$, CNT%)
ILRD (BD%, RD$, CNT%)
ILRDA (BD%, RD$, CNT%)
ILWRT (BD%, WRT$, CNT%)
ILWRTA (BD%, WRT$, CNT%)
•
All functions except
ILFIND
return the value of
IBSTA
. This
permits the following construct:
IF IBRD (BD%, RD%, CNT%) < 0 THEN CALL
GPIBERROR
Table 4A.4 contains a complete list of the new QuickBASIC GPIB
functions, their parameters, and a short description of each.