National Instruments GPIB-PC - Manual (Page 47)

GPIB-PC Functions — Introduction Section Three
GPIB-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 GPIB
There is a difference between clearing or initializing devices and
clearing or initializing the GPIB itself.
Clearing the Device
The Selected Device Clear (SDC) command that is sent by the IBCLR
function resets internal functions of the device, such as causing a digital
multimeter to change its function, range, and trigger mode back to
default settings.
Clearing the GPIB
The Interface Clear (IFC) command initializes the GPIB and the bus
interface circuits of all attached devices without affecting internal
functions. IFC is sent automatically when the first device function is
called.
A device function is a function that references a device such as the four
already 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 To
Local (GTL) and appropriate addressing commands to the device.
Placing a Device in Remote Mode
The first device function call after power-on, in addition to sending the
IFC command as previously described, also places the device in remote
program mode by setting the GPIB Remote Enable (REN) line and
addressing the device to listen.