BASICA/QuickBASIC GPIB-PC Function Calls Section Four AGPIB-PC User Manual 4A-66 ©National Instruments Corp.BASICA/QuickBASIC BASICA/QuickBASICIBRSC IBRSCPurpose: Request or release System ControlFormat: CALL IBRSC (BD%,V%)Remarks: BD% specifies an interface board. If V% is non-zero,functions requiring System Controller capability aresubsequently allowed. If V% is zero, functions requiringSystem Controller capability are disallowed.The IBRSC function is used to enable or disable thecapability of the GPIB-PC to send the Interface Clear(IFC) and Remote Enable (REN) messages to GPIBdevices using the IBSIC and IBSRE functionsrespectively. The interface board must not be SystemController to respond to Interface Clear sent by anotherController.In most applications, the GPIB-PC will always be theSystem Controller. In other applications, the GPIB-PC willnever be the System Controller. In either case, the IBRSCfunction is used only if the computer is not going to beSystem Controller for the duration of the programexecution. While the IEEE-488 standard does notspecifically allow schemes in which System Control can bepassed dynamically from one device to another, the IBRSCfunction would be used in such a scheme.When IBRSC is called and an error does not occur, theprevious value of ist is stored in IBERR%.Refer also to Table 2.1.
