- GPIB-PC User Manual for the IBM Personal Computer and Compatibles April 1988 Edition Part Number 320014-01

Section Three GPIB-PC Functions — Introduction
©National Instruments Corp. 3-3 GPIB-PC User Manual
IBFIND (bdname,bd)
IBFIND returns a unit descriptor associated with the name of the
device. When the software is installed, a description of each device is
placed in an internal reference table accessible by the handler. This
description includes the GPIB address, end-of-string (EOS) modes,
timeout selection, and a name for the device.
Group II
Group II functions offer additional high-level device services often
needed in common instrument control applications. Group II functions
are as follows:
• IBRSP,
• IBCLR,
• IBTRG, and
• IBLOC.
IBRSP (bd,spr)
IBRSP serially polls a device and returns its status response. The
response consists of a single byte in which the hex 40 bit is set if the
device is requesting service and asserting Service Request (SRQ).
Here are examples of a Tektronix 4041 BASIC SRQ handler call and
the corresponding IBRSP call. In this case, the device being polled is
the plotter and is at GPIB address 7:
POLL STATUS, ADDRESS; 7
CALL IBRSP (PLTR%,STATUS%)
In both cases, the plotter's status response is stored in the variable
STATUS.
Unless disabled during software configuration, any device function call
will automatically conduct serial polls if SRQ is asserted on GPIB. This
automatic serial polling is discussed in Section Four.