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Figure 3-1. example of remote operation, 13 scpi programming, 1 scpi messages – KEPCO EL Series Electronic Load Operator Manual P/N 243-1295 Firmware Version 3.22 through 3.41 User Manual

Page 42: 2 common commands/queries, Scpi programming -8, Scpi messages -8, Common commands/queries -8, Example of remote operation -8

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SERIES EL 062011

FIGURE 3-1. EXAMPLE OF REMOTE OPERATION

3.13

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
commands are sent to the Series EL Electronic Load as ASCII output strings within the selected
programming language (PASCAL, C, BASIC, LABVIEW, etc.) in accordance with the interface
protocol used.

Different programming languages (e.g., BASIC, C, PASCAL, LABVIEW, etc.) have different
ways of representing data that is to be put on the control bus. It is up to the programmer to
determine how to output the character sequence required for the programming language used.
If the optional IEEE 488.2 (GPIB) interface is used, address information (GPIB address) must
be included before the command sequence.

3.13.1

SCPI MESSAGES

There are two kinds of SCPI messages: program messages from controller to electronic load,
and response messages from the electronic load to the controller. Program messages consist of
one or more properly formatted commands/queries and instruct the electronic load to perform
an action; the controller may send a program message at any time. Response messages con-
sist of formatted data; the data can contain information regarding operating parameters, elec-
tronic load state, status, or error conditions.

3.13.2

COMMON COMMANDS/QUERIES

Common commands and queries are defined by the IEEE 488.2 standard to perform overall
electronic load functions (such as identification, status, or synchronization) unrelated to specific
electronic load operation (such as setting voltage/current). Common commands and queries are
preceded by an asterisk (*) and are defined and explained in Appendix A. Refer also to syntax
considerations (PARs 3.13.3.8 through 3.13.6).

MODE CURR

Sets mode to current.

CURR 0.1

Sets current level to low level.

INPUT ON

Causes load to engage UUT and draw current. LOAD pushbutton illu-

mination changes from green to amber and VOLTS, AMPS and KW
displays show measured parameters.

CURR 100

Sets current level to 100 amperes.

MEAS:CURR?

Request that Series EL measure current. Unit responds with 100.0.

MEAS:VOLT?

Request that Series EL measure voltage. Unit responds with 12.5.

INPUT OFF

Causes load to disengage UUT and stop drawing current.