HP 4278A - Page 71

4-2-5. HP-IB BUS COMMANDS
The 4278A will respond to the following bus commands. HP 200 series BASIC statements
are used in the description that follows.
1. ABORT I/O (IFC):
ABORT I/O halts all bus activity and causes the 4278A to become deselected.
ABORT 7
2. CLEAR LOCKOUT/SET LOCAL:
CLEAR LOCKOUT/SET LOCAL removes devices on the bus from the lockout
mode and returns them to local (front panel) control. The difference between this
and LOCAL is in the addressing method.
LOCAL 7
3. DEVICE CLEAR (SDC or DCL):
This command may be addressed (SDC: selected device clear) or unaddressed
(DCL: clears all devices). The 4278A will initialize itself when this command is
received. It is good programming practice to begin a program with this
command.
CLEAR 7:clears all devices on port 7
CLEAR 717:clears the instrument addressed at 17
4. LOCAL (GIL):
LOCAL returns control of a listening device to front panel control.
LOCAL 717
5. LOCAL LOCKOUT (LLO):
LOCAL LOCKOUT disables the LOCAL key of all devices on the bus. After this
command is sent you will be unable to operate the 4278A from the front panel.
Execute the LOCAL command to undo LOCAL LOCKOUT.
LOCAL LOCKOUT 7
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