Ametek Amrel PLA 2U, Operation Manual

Page: 92 / 162

M470039-01 REV-F Page 91
SYNTAX OVERVIEW
Use of the Colon (:)
A co lon is used to sepa ra te comma nd mnemonics. It indica tes a move down in bra nch level of the command tree.
The command follows a colon is a sub command of the comma nd immedia te before the colon. When colon
precedes the first command mnemonic of a messa ge unit, it becomes root specifie r. Its a ction pla ces the pa rser
(decoder) a t the root of the command tree. Pa rser ca n only tra vel downwa rd the comma nd tree. If a nother
comma nd a t different branch needs to be executed, a root specifier (colon) is required to pla ce pa rser a t origin a nd
a complete pa th from root level should a lso be defined.
Use of the Semicolon (;)
A semico lon is used to sepa ra te two command sta tements with the sa me comma nd messa ge string. The semicolon
does not cha nge loca tion of the pa rser in the comma nd tree. On ly comma nd sta tements that a re in the current pa th
of the first comma nd sta tement ca n be combined to form a comma nd messa ge.
Use of the Spa ce ( )
A white spa ce is used to sepa ra te a pa rameter (da ta ) from a command mnemonic. When a comma nd sta tement
includes pa ra meter, da ta a lwa ys follows the la st keyword of a comma nd.
Use of the Comma (,)
A comma is used to sepa ra te a dja cent pa rameters if a comma nd requires more tha n one pa ra meter.
Use of the Query (?)
A query command is used to instruct the instrument to send a response messa ge. Queries return either mea sured
va lues or interna l instrument setting. When a keyword is follo wed by a question ma rk, it becomes a query. The ?
follows the la st keyword of a comma nd sta tement. You should rea d ba ck the result of first query before you send
out a nother query or comma nd. Otherwise, returned da ta will be lost.
Common Commands:
Comma nds sta rting with a * a nd three-letter mnemonic a re ca lled common comma nds. They a re genera lly not
rela ted to specific device opera tion but to perform the identica l function for a ll instruments tha t a re complia nt with
the IEEE-488.2 interfa ce sta nda rd. Common comma nds ca n be mixed in with re gula r Electronic Loa d comma nds.
The common command will be executed without a ffecting the position of the pa rser.
Root-Level Comma nds:
The root-level commands a re those comma nds specific to the Electronic Loa d. They a re device specific a nd can be
mixed with common commands.
LANGUAGE DICTIONARY
The synta x and pa ra meters for the IEEE 488.2 common comma nds and SCPI commands used by the Electronic Load is
presented in this section. The section sta rts with description for common comma nds a nd then follows by SC PI commands
specific to the electronic loa d.
COMMAND STRUCTURE
The electronic loa d ha s two comma nd types for GPIB a nd RS-232 interfa ce.
Programming commands
Query comma nds
System comma nds
Progra mming commands send progra mming instructions or va lues to the electronic load to control the CV/CC/CR/CP
functions. There a re two types of commands, the SCPI comma nd and instruction commands tha t co -exist in the progra m.