KEPCO TMA 4882-27 - Manual (Page 34)

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TMA 4882-27 021910
3. Never program both the active and complementary limit parameter to zero. This can result in
long response times. Set the active parameter to zero and the complementary limit parame-
ter to a minimum, e.g., 10% of maximum, to ensure that the active mode is defined.
3.6 SCPI PROGRAMMING
SCPI (Standard Commands for Programmable Instruments) is a programming language con-
forming to the protocols and standards established by IEEE 488.2 (reference document ANSI/
IEEE Std 488.2, IEEE Standard Codes, Formats, Protocols, and Common Commands). SCPI com-
mands are sent to the TMA 4882-27 controller as output strings within the selected program-
ming language (PASCAL, BASIC, etc.) in accordance with the manufacturer’s requirements for
the particular GPIB interface card used.
Different programming languages (e.g., BASIC, C, PASCAL, etc.) have different ways of repre-
senting data that is to be put on the IEEE 488 bus. It is up to the programmer to determine how
to output the character sequence required for the programming language used. Address infor-
mation (GPIB address) must be included before the command sequence. (See PAR. 2.2.1 to
establish the TMA 4882-27 controller GPIB address.)
3.6.1 SCPI MESSAGES
There are two kinds of SCPI messages: program messages from controller to power supply,
and response messages from the power supply to the controller. Program messages consist of
one or more properly formatted commands/queries and instruct the power supply to perform an
action; the controller may send a program message at any time. Response messages consist of
formatted data; the data can contain information regarding operating parameters, power supply
state, status, or error conditions.
3.6.2 COMMON COMMANDS/QUERIES
Common commands and queries are defined by the IEEE 488.2 standard to perform overall
power supply functions (such as identification, status, or synchronization) unrelated to specific
power supply operation (such as setting voltage/current). Common commands and queries are
preceded by an asterisk (*) and are defined and explained in Appendix A (see Table 3.4). Refer
also to syntax considerations (PARs 3.6.4 through 3.6.7).
3.6.3 SCPI SUBSYSTEM COMMAND/QUERY STRUCTURE
Subsystem commands/queries are related to specific power supply functions (such as setting
output voltage, current limit, etc.) Figure 3-2 is a tree diagram illustrating the structure of SCPI
subsystem commands used in the TMA 4882-27 controller with the “root” at the left side, and
specific commands forming the branches. The subsystem commands are defined and
explained in Appendix B (see Table 3-5).