National Instruments GPIB-PC - 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.