KEPCO BIT 232F - Manual (Page 24)

4-2 BIT 232 022800
Sample programs provided in Appendices D through G guide the user in setting up a program to
communicate with the BOP via the BIT 232/BIT 232-F Interface Card.
4.4 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 BIT Card as output strings within the selected programming language
(PASCAL, BASIC, etc.) in accordance with the manufacturer’s requirements for the particular
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 RS232C bus. It is up to the programmer to determine how to
output the character sequence required for the programming language used. Address informa-
tion must be included before the command sequence.
4.4.1 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.
4.4.2 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 4-4). Refer
also to syntax considerations (PARs 4.4.3 through 4.4.6).
4.4.3 SCPI SUBSYSTEM COMMAND/QUERY STRUCTURE
Subsystem commands/queries are related to specific power supply functions (such as setting
output voltage, current limit, etc.) Figure 4-1 is a tree diagram illustrating the structure of SCPI
subsystem commands used in the BIT Card with the “root” at the left side, and specific com-
mands forming the branches. The subsystem commands are defined and explained in Appendix
B (see Table 4-4).