PLZ-5W Series Electronic Load

Commnunication Interface Mannual


Overview of commands

About Commands

The information that is transferred between the controller (the PC) and the PLZ-5W is referred to as "messages".
The PLZ-5W uses the SCPI language for these messages.

The messages that the PC sends to the PLZ-5W are commands. The messages that the PLZ-5W sends to the PC are responses.

Command hierarchy

SCPI is an ASCII-based command language that was designed for test and measuring equipment. The command structure is composed of the common roots and nodes that are the building blocks of the SCPI subsystem. A command consists of a program header, parameters, and punctuation marks.

The following table uses the SOURce subsystem as an example to explain the hierarchy.


Program header Parameter Node level
SOUR:   Root node
  VOLT 2nd level
    :PROT 3rd level
      :STAT <bool> 4th level
  PROG 2nd level
    :SEL 3rd level
      :REN <string> 4th level

A colon (:) separates a higher node from a lower node.

Command Syntax

In this manual, SCPI commands are expressed in the following format.

[:SOURce]:CURRent:SLEWrate {<numeric>|MINimum|MAXimum}

Basic Notation

  • You can use long form and short form.
    Long form: SCPI commands are written with all the characters.
    Short form: SCPI commands are written by omitting the lowercase characters.
  • No distinction is made between uppercase and lowercase.
    CURRENT, Current, and current are all acceptable as long form notations.
    CURR, Curr, and curr are all acceptable as short form notations.
  • A space separates a program header and its parameters.
  • Multiple parameters are separated by commas.
  • Multiple commands are separated by semicolons.
    VOLTage:PROTection:STATe ON;LOWer 10V
    Input of the following two commands is equivalent to input of the above command.
    VOLTage:PROTection:STATe ON
    VOLTage:PROTection:LOWer 10V
    By using colons and semicolons, you can concatenate commands of different subsystems.
    TRIGger:ACQuire:SOURce BUS;:INITiate:ACQuire
  • The maximum length of a command that you can transmit on a single line is 128 bytes.

Special symbols

The special symbols that are used in SCPI commands are explained below.

  • Characters and numbers enclosed between {} and delimited by “|” indicate that one of the delimited items is to be selected.
    Do not include the { and } symbols in the actual program.
  • <> denotes a parameter.
    Do not include <> in the actual program.
  • [ ] denotes optional data.
    The data enclosed in square brackets ([ ]) can be omitted. If omitted, the default value is applied.
    Do not include the [ and ] symbols in the actual program.


You can query the PLZ-5W settings and status.

To make a query, append a question mark to the end of the program header section. If the query has parameters, insert a space after the question mark, and then write the parameters.



This is the response to a query. Responses are messages sent to the host PC from the PLZ-5W. They inform the PC about the status and measured values of the PLZ-5W.


If you want to send two queries on separate lines, send the second query after you have received the response to the first one.

Program terminator

All commands must be terminated with a valid terminator.

receptionLF LF or EOM LF or ENDLF
transmission LF LF+EOM LF+END LF

When you terminate a command string, the path is reset to the root level.


CR (ASCII 0x0D) is not a terminator.

Common commands

There are commands that are common to the IEEE-488.2 and SCPI standards for functions such as resetting devices and performing self-diagnoses. These common commands start with an asterisk (“*”). These commands may have one or multiple parameters.



Overview of Command

Command (function search)

Command (ABC search)

Command (Sub-system search)




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Communication Interface Manual