KEPCO EL Series Electronic Load Operator Manual P/N 243-1295 Firmware Version 3.12 (Unit Rev 2) - Manual (Page 49)

SERIES EL 070110
3-15
of a program message may be separated by a semicolon (;) without repeating the root
keyword.
• If a program message has more than one message unit, then a colon (:) must precede
the next keyword in order to set the parser back to the root (otherwise the next keyword
will be taken as a subunit of the previous message unit).
e.g., the command meas:volt?;curr? will read output voltage and output current
since both volt? and curr? are interpreted as subunits of the meas command.
• Several commands may be sent as one message; a line feed terminates the message.
Commands sent together are separated by a semicolon (;). The first command in a mes-
sage starts at the root, therefor a colon (:) at the beginning is not mandatory.
e.g., the command meas:volt?;:curr? will read output voltage and programmed cur-
rent since the colon preceding curr? indicates that curr? is not part of the meas com-
mand and starts at the root.
• UPPER case letters in mnemonics are mandatory (short form). Lower case letters may
either be omitted, or must be specified completely (long form)
e.g., PROTection (long form) has the same effect as PROT (short form).
• Commands/queries may be given in upper/lower case (long form)
e.g., SoUrCe is allowed.
• Text shown between brackets [ ] is optional.
e.g., :[SOUR:]VOLT[:LEV][:AMPL]? has the same effect as :VOLT?
3.10.7 STATUS REPORTING
The status reporting of the EL Series Electronic Load follows the SCPI and IEEE 488.2 require-
ments. The serial poll response of the EL provides summary bits of the status and error report-
ing system. The simplest status report is the command valid reporting and data availability. The
successful decoding of a command string generates no error and is indicated by the bit 3 of the
serial poll response being a zero. The setting of bit 4 in the status byte indicates data is avail-
able to the controller in response to a query.
3.10.7.1 STATUS REPORTING STRUCTURE
The status reporting of the EL uses multiple status register sets, illustrated in Figure 3-5. These
register sets are Channel Status, Channel Summary, Questionable, Operation, Standard Event
and Status Byte/Service Request registers. All registers are 16-bit registers except the Standard
Event and Status Byte/Service Request registers which are 8 bits. The Channel Status, Opera-
tion Status and Questionable registers all have condition registers which are associated with
two related registers: an event register which holds unlatched events reported in real-time by
the instrument and is cleared by reading the register, and an enable register which allows the
contents of the event register to be passed through to set the associated condition register.