KEPCO BOP-MG 1KW, Operator'S Manual

Page: 129 / 198

BOP HIPWR 111315
3-61
3.6.4 PROGRAM MESSAGE STRUCTURE
SCPI program messages (commands from controller to power supply) consist of one or more
message units
ending in a
message terminator
. The message terminator is not part of the syntax; it
is defined by the way your programming language indicates the end of a line (“newline” charac-
ter). Sending a character with EOL line asserted is another way of sending a message termina-
tor. The message unit is a keyword consisting of a single command or query word followed by a
message terminator (e.g., CURR?<newline> or TRIG<end-of-line>). The message unit may
include a data parameter after the keyword separated by a space; the parameter is usually
numeric (e.g., CURR 5<newline>), but may also be a string (e.g., OUTP ON<newline>). Figure
3-19 illustrates the message structure, showing how message units are combined. The follow-
ing subparagraphs explain each component of the message structure.
NOTE: An alternative to using the message structure for multiple messages defined in the fol-
lowing paragraphs is to send each command as a separate line. In this case each com-
mand must use the full syntax shown in Appendix B.
FIGURE 3-19. MESSAGE STRUCTURE
CURR:LEV 3.5;:OUTP ON;:CURR?<NL>
MESSAGE TERMINATOR
KEYWORD
QUERY INDICATOR
ROOT SPECIFIER
MESSAGE UNIT SEPARATOR
DATA
KEYWORD
KEYWORD
KEYWORD SEPARATOR
KEYWORD
MESSAGE UNIT SEPARATOR
DATA
MESSAGE UNIT
DATA SEPARATOR
DATA SEPARATOR
ROOT SPECIFIER