GPIB-PC Functions — Introduction Section ThreeGPIB-PC User Manual 3-4 ©National Instruments Corp.IBCLR (bd)IBCLR clears the device by sending to it the Selected Device Clear(SDC) and appropriate addressing commands.Clearing the Device Versus Clearing the GPIBThere is a difference between clearing or initializing devices andclearing or initializing the GPIB itself.Clearing the DeviceThe Selected Device Clear (SDC) command that is sent by the IBCLRfunction resets internal functions of the device, such as causing a digitalmultimeter to change its function, range, and trigger mode back todefault settings.Clearing the GPIBThe Interface Clear (IFC) command initializes the GPIB and the businterface circuits of all attached devices without affecting internalfunctions. IFC is sent automatically when the first device function iscalled.A device function is a function that references a device such as the fouralready described: IBRD, IBWRT, IBRSP, and IBCLR.IBTRG (bd)IBTRG triggers the device by sending to it the Group Execute Trigger(GET) and appropriate addressing commands.IBLOC (bd)IBLOC places the device in local program mode by sending the Go ToLocal (GTL) and appropriate addressing commands to the device.Placing a Device in Remote ModeThe first device function call after power-on, in addition to sending theIFC command as previously described, also places the device in remoteprogram mode by setting the GPIB Remote Enable (REN) line andaddressing the device to listen.
