Product Manual

LCD and Remote Interface Setup Procedures
IEEE-488 Interface Overview 5
5-7
Table 5-1 gives the possible operation state transitions. For more information about
IEEE-488 GPIB messages, see the “IEEE-488 Interface Overview” section of this
chapter.
Table 5-1. Operating State Transitions
From To Front Panel GPIB Message Serial Command
Local
Remote
Local with Lockout
MLA (REN
True) LLO
REMOTE
LOCKOUT
Remote
Local
Remote with
Lockout
Local 0 key
GTL or REN
False
LLO
LOCAL LOCKOUT
Local with
Lockout
Local
Remote with
Lockout
REN False
MLA (REN
True)
LOCAL REMOTE
Remote with
Lockout
Local
Local with Lockout
REN False
GTL
LOCAL
IEEE-488 Interface Overview
The IEEE-488 parallel interface sends commands as data and receives measurements and
messages as data. The maximum data exchange rate is 1 Mbyte per second, with a
maximum distance of 20 meters for the full length of the cable connections. One cable
must not be more than 4 meters.
Some commands are used only for RS-232 serial operation because these functions must
be implemented as IEEE uniline (single control line) bus management messages per the
IEEE Standards. For example, the command REMOTE can be sent as data over the
IEEE-488 interface to put the Product into remote operation mode, but it is not because
the IEEE Standards use the remote function to be sent to the device as the uniline
message REN. This is also true for some other commands and functions, as shown in
Table 5-2 with their RS-232 equivalents.
Table 5-2. RS-232 Emulation of IEEE-488 Messages
IEEE-488 Message RS-232 Equivalent
GTL LOCAL command
GTR REMOTE command
LLO LOCKOUT command
SDC, DCL (not emulated on RS-232)
GET (not emulated on RS-232)
SPE, SPD (not emulated on RS-232)
UNL, UNT
(
not emulated on RS-232
)
The IEEE-488 interface uses the IEEE Standards 488.1 and 488.2 as its basis. For more
information, refer to the IEEE-488.1 and IEEE-488.2 standards.