Specifications

Section 4
Programming
4.1 OVERVIEW
This section provides detailed information on programming the SEFRAM 4451 via the IEEE
488 bus (GPIB - General Purpose Interface Bus). The SEFRAM 4451 is programmable over the
IEEE 488 bus, and its message protocol is compatible with IEEE 488.2. The device command
set is compatible with the SCPI 1992.0 standard. The SCPI standard does not cover all the
needs of the SEFRAM 4451, and so the standard has been added where necessary.
The command syntax as defined by the IEEE 488.2 and SCPI standards is briefly explained in
the following sections. Users who have experience programming GPIB instruments may skip
these paragraphs, and go directly to where the individual command syntax is given. Users
wishing to gain further insight should consult the standards.
4.2 DEVICE STATE
The device may be in one of the four possible states described below. The transition between
states is defined by IEEE 488.
4.2.1 Local State (LOCS)
In the LOCS the device may be operated from the front panel only. Its settings may be queried
over the GPIB, but not changed. Commands that do not affect the signal being output by the
instrument are accepted.
4.2.2 Local with Lockout State (LWLS)
In the LWLS the device may be operated from the front panel only. Its settings may be queried
over the GPIB, but not changed. Commands that do not affect the signal being output by the
instrument are accepted. The difference between the LOCS and the LWLS is that from the
LWLS the device may enter the Remote With Lockout State.
4.2.3 Remote State (REMS)
In the REMS the device may be operated from the GPIB. Actuating any front panel key will
cause the device state to revert to the LOCS.
4.2.4 Remote with Lockout State (RWLS)
In the RWLS the device is operable only from the GPIB. Front panel operation may be returned
by either sending an appropriate IEEE 488 command, or by cycling the device power.
4.3 INTERFACE FUNCTION SUBSETS
The following interface function subsets are implemented in the SEFRAM 4451:
SH1, AH1, T6, L4, SR1, RL1, PP0, DC1, DT1, E2, C0
4.4 DEVICE ADDRESS
The GPIB address of the device may be set to any value from 0 to 31. The address may be
changed from the front panel, using the numeric keypad or the rotary encoder, or via the GPIB
itself using the command:
:SYSTem:COMMunicate:GPIB:ADDRess