Martel Electronics 3001 - Manual (Page 45)

9.6 Using Commands
Communications between the controller and the 3001 consist 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 specific RS-232 only
commands as described in the subsection Commands for RS-232 Only below.
For more detailed information on IEEE command structures, see the IEEE 488.2
standard.
Refer to section 10 for more detailed information about the commands referenced in this
section.
All commands, units, and text data may be entered in UPPER or lower case letters. The
3001 converts all lower case letters to upper case before processing.
9.6.1 Types of Commands
The commands for the 3001 can be grouped into the following categories based on how
they function.
a) Device-Dependent Commands
Device-dependent commands are unique to the 3001. An example of a device-
dependent command is:
OUT 1 V
This command instructs the 3001 to source 1 volt DC.
b) 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 asterisk (*)
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?
This command instructs the 3001 to return the instrument identification string.
c) Query Commands
Query commands request information, which may be returned as the
command executes, or may be placed in a buffer until requested later. Query
commands always end with a question mark. An example of a query
commands is:
RANGE?
This command instructs the 3001 to return the present DC voltage output
range.
d) 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 dedicated control lines. The rest of the
interface messages are sent over the data lines with the ATN signal true. All
device-dependent and common commands are sent over the data lines with
the ATN signal false.
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