Martel Electronics M2000 - Manual (Page 11)

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Table 4. 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 is based on the IEEE Standards 488.1 and 488.2. For detailed infor-
mation, refer to the IEEE-488.1 and IEEE-488.2 standards.
Using Commands
Communications between the controller and the M2000 consists of commands, queries, and
interface messages. Although the commands are based on the 488.2 standard, they can be
used on either the IEEE-488 or RS-232 interface, except for a few specialized RS-232 com-
mands described in "Commands for RS-232 Only." (For more information on command struc-
tures, see the IEEE 488.2 standard.)
Refer to Chapter XI, "Remote Commands" when you require additional information about
command references used in this chapter.
All commands and units may be entered in UPPER or lower case.
Types of Commands
The commands for the M2000 can be grouped into one or more categories, depending on
how they function. Each category is described below.
Device-Dependent Commands
Device-dependent commands are unique to the M2000. An example of a device-dependent
command is,
OUT 1 V
instructing the M2000 to source 1 volt dc.
Common Commands
Common commands are defined by the IEEE 488.2 standard and are common to most bus
devices. Common commands always begin with an * character. Common commands are
available whether you are using the IEEE-488 or RS-232 interface for remote control. An
example of a common command is,
*IDN?
instructing the M2000 to return the instrument identification string.
Query Commands
Query commands request information, which is returned as the command executes, or
placed in a buffer until requested. An example of a query, which always ends with a question
mark, is,
RANGE?
returning the M2000 dc voltage output range.
Interface Messages (IEEE-488)
Interface messages manage traffic on the IEEE-488 interface bus. Device addressing and
clearing, data handshaking, and commands to place status bytes on the bus are all directed
by interface messages. Some of the interface messages occur as state transitions of dedicat-