KEPCO BIT 232F - Manual (Page 25)

BIT 232 022800 4-3
FIGURE 4-1. TREE DIAGRAM OF SCPI COMMANDS USED WITH BIT 232/BIT 232-F INTERFACE CARD
4.4.4 PROGRAM MESSAGE STRUCTURE
SCPI program messages (commands from controller to power supply) consist of one or more
message units ending in a message terminator (required by Kepco power modules). The message
terminator is not part of the syntax; it is defined by the way your programming language indi-
cates the end of a line (such as a “newline” or “end-of-line” character). 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 4-2 illustrates the message struc-
ture, showing how message units are combined. The following 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.
4.4.4.1 KEYWORD
Keywords are instructions recognized by a decoder within the BIT Card, referred to as a
“parser.” Each keyword describes a command function; all keywords used by the BIT Card are
listed in Figure 4-1.
Each keyword has a long form and a short form. For the long form the word is spelled out com-
pletely (e.g. STATUS, OUTPUT, VOLTAGE, and TRIGGER are long form keywords). For the
short form only the first three or four letters of the long form are used (e.g., STAT, VOLT, OUTP,
and TRIG). The rules governing short form keywords are presented in Table 4-5.
INITiate
[:IMMediate]
:CONTinuous
MEASure
:CURRent?
:VOLTage?
[SOURce:]
VOLTage
[:LEVel]
[:IMMediate]
:TRIGgered
CURRent
[:LEVel]
[:IMMediate]
:TRIGgered
FUNCtion
:MODE
ROOT : (colon)
STATus
:OPERation
:CONDition?
:ENABle
[:EVENt]?
:PRESet
:QUEStionable
:CONDition?
:ENABle
[:EVENt]?
SYSTem
:ERRor?
:LANGuage