Ceyear 1435 Series Use and maintenance manual

1435 Series
Signal Generators
Program Control Manual
China Electronics Technology Instruments Co., Ltd.

This manual is applied to the following models of signal generators, based on firmware version 1.0 and
above.
1435A signal generator (9kHz - 3GHz)
1435B signal generator (9kHz - 6GHz)
1435C signal generator (9kHz - 12GHz)
1435D signal generator (9kHz - 20GHz)
1435F signal generator (9kHz - 40GHz)
1435A-V signal generator (9kHz - 3GHz)
1435B-V signal generator (9kHz - 6GHz)
Options other than standard accessories are as follows:
115dB programmable step attenuator: extend the dynamic range of output power;
Analog modulation: add the function of analogue modulation, including AM, FM, Φ M, low-frequency
(LF) output;
Pulse modulation: add the function of pulse modulation, with the minimum pulse width of 100ns;
Narrow pulse modulation: add the function of pulse modulation, with the minimum pulse width of
20ns;
Multi-function generator: add more rich analog modulation signal format;
Low phase noise: optimize SSB phase noise, 10GHz@10kHz: -113dBc/Hz;
High power output: increase the maximum output power;
High stability time base option: internal time base aging rate;
Calibration certificate: instrument calibration;
N-type connector for RF output: N-type connector for RF output is applicable for 1435D;
RF output moved to the rear panel: RF output on the rear panel;
Portable handle: 3U handle;
Rack mounting kit: mounting kit for upper cabinet;
Aluminum alloy transport case: high strength light aluminum alloy transport case with handle and
universal roller makes transportation convenient;
English kits: English panel, English manual, English interface and English operating system;
English options: English menu, English panel, etc., for export;
Version: A.1 2018.12, China Electronics Technology Instruments Co., Ltd.
Add.: No. 98, Xiangjiang Road, Qingdao Economic & Technological Development Zone, Shandong, China
Free customer service number: 800-868-7041
Technical support: 0532-86889847 86897262
Fax: [phone] 86897258
Website: www.ceyear.com
Email: [e-mail]
Postal code: 266555

Foreword
Thank you for choosing and
using 1435 series signal
generator developed and
produced by China Electronics
Technology Instruments Co.,
Ltd.! Integrating high,
sophisticated and cutting-edge
technologies, our products offer
high cost performance among
similar products.
With maximally meeting your
requirements as our duty, we
will provide you with
high-quality measuring
instruments as well as
first-class after-sales service.
With the consistent tenet of
"high quality and considerate
service", we promise to provide
the users with satisfactory
products and services.
Manual No.
2.827.1101CK
Version
A.1 2018.12
China Electronics Technology
Instruments Co., Ltd.
Manual Authorization
The contents of this manual are
subject to change without
notice. The final right to
interpret the contents and
terms used in this manual
belongs to China Electronics
Technology Instruments Co.,
Ltd.
The copyright of this manual
belongs to China Electronics
Technology Instruments Co.,
Ltd. No organization or
individual is allowed to modify
or alter the contents of this
manual or copy or disseminate
this manual for profit without
our authorization. China
Electronics Technology
Instruments Co., Ltd. reserves
the right to take legal actions
against any infringer.
Product Warranty
The warranty period of this
product is 18 months from the
date of shipment. During the
warranty period, the
manufacturer will repair or
replace damaged parts
according to actual conditions.
For this purpose, the user shall
return the product to the
manufacturer and prepay the
mailing fee. The manufacturer
will return the fee to the user
together with the product after
maintenance.
Product Quality
Certification
This product is guaranteed to
meet the specifications in this
manual from the date of
shipment. The calibration and
measurement are completed
by measuring bodies with
national qualification, with
relevant data to be provided for
reference by users.
Quality/Environmental
Management
This product complies with the
quality and environmental
management systems during
R&D, manufacturing and
testing. China Electronics
Technology Instruments Co.,
Ltd. already has the required
qualifications and has passed
the certification of ISO 9001
and ISO 14001 management
systems.
Safety Precautions
The "Note" symbol indicates
some important information
which will not cause danger. It
reminds the user to pay
attention to certain operation
process, operation method or
the like. Failure to observe the
rules or operate correctly may
cause damage to the
instrument or loss of important
data. Proceed to the next step
only after fully understanding
and meeting the note
conditions indicated.
The "Tips" symbol indicates
information tips. It reminds the
user to pay attention to the
instrument or certain operation
process, operation method or
the like.
The purpose is to guide the
instrument operator to use the
instrument correctly.
Note
Tip

1435 Series Signal Generators
Contents
1
Contents
1. Manual Navigation......................................................................................1
1.1 About the Manual...........................................................................................................1
1.2 Related Documents .......................................................................................................2
2. Remote Control...........................................................................................3
2.1 Remote Control Basics..................................................................................................3
2.1.1 Program Control Interface......................................................................................................... 3
2.1.2 Message.................................................................................................................................... 6
2.1.3 SCPI........................................................................................................................................... 6
2.1.4 Command Sequence and Synchronization............................................................................. 14
2.1.5 Status Reporting System......................................................................................................... 16
2.1.6 Programming Precautions....................................................................................................... 25
2.2 Instrument Program Port and Configuration ................................................................25
2.2.1 LAN.......................................................................................................................................... 25
2.2.2 GPIB ........................................................................................................................................ 27
2.3 I/O Library....................................................................................................................28
2.3.1 Overview of I/O Library............................................................................................................ 28
2.3.2 Installation and Configuration of I/O Library............................................................................ 29
3. Program control commands......................................................................31
3.1 Description of Commands............................................................................................31
3.2 Common Commands...................................................................................................31
*IDN? ................................................................................................................................................ 32
*RCL <Value>................................................................................................................................... 32
*RST ................................................................................................................................................. 32
*SAV <Value>................................................................................................................................... 32
*CLS.................................................................................................................................................. 32
*ESE <Value>................................................................................................................................... 32
*ESR?............................................................................................................................................... 32
*STB?................................................................................................................................................ 33
*TRG................................................................................................................................................. 33

1435 Series Signal Generators
Contents
2
*TST?................................................................................................................................................ 33
3.3 Instrument Subsystem Command................................................................................33
3.3.1 OUTPut Subsystem................................................................................................................. 33
3.3.2 FREQuency Subsystem.......................................................................................................... 34
3.3.3 POWer Subsystem.................................................................................................................. 38
3.3.4 LIST Subsystem ...................................................................................................................... 45
3.3.5 LFOutput Subsystem............................................................................................................... 50
3.3.6 SWEep Subsystem.................................................................................................................. 59
3.3.7 PULM Subsystem.................................................................................................................... 63
3.3.8 AMPLitude MODulation Subsystem........................................................................................ 71
3.3.9 FREQuency MODulation Subsystem...................................................................................... 83
3.3.10 PHASe MODulation Subsystem............................................................................................ 94
3.3.11 Digital MODulation Subsystem............................................................................................ 106
3.3.12 MEMory Subsystem ............................................................................................................ 135
3.3.13 ROSCillator Subsystem....................................................................................................... 137
3.3.14 SYSTem Subsystem ........................................................................................................... 137
4. Programming Examples..........................................................................141
4.1 Basic Operation Examples.........................................................................................141
4.1.1 VISA Library........................................................................................................................... 141
4.1.2 Example Runtime Environment............................................................................................. 142
4.1.3 Initialize and Set Default State.............................................................................................. 142
4.1.4 Send Setting Command ........................................................................................................ 143
4.1.5 Read the State of Measuring Instrument .............................................................................. 144
4.1.6 Command Synchronization................................................................................................... 144
4.2 Advanced Operation Examples .................................................................................145
4.2.1 Set Point Frequency at LAN Interface and Query................................................................. 145
4.2.2 Set Point Frequency at GPIB Interface and Query............................................................... 148
5. Error Description.....................................................................................149
5.1 Errors.........................................................................................................................149
5.1.1 Error Description.................................................................................................................... 149
5.2 Method to Obtain After-sales Services.......................................................................151

1435 Series Signal Generators
Contents
3
5.2.1 Contact Us............................................................................................................................. 151
5.2.2 Package and Mailing............................................................................................................. 151
Annexes.........................................................................................................153
Annex A Zoom Table of SCPI Classified by Subsystem..................................................153
Annex B Zoom Table of Errors ........................................................................................175

1. Manual Navigation
1.1 About the Manual
1
1. Manual Navigation
This chapter introduces the function, chapter structure and main content of the programming manual for
1435 series signal generator, as well as the instrument related documents provided for users.
About the Manual ····················································································1
Related Documents·················································································2
1.1 About the Manual
This manual introduces the methods for remote control of 1435 series signal generator and application
of SCPI. Meanwhile, in order to make it convenient for users to quickly master the remote control
programming methods, some programming examples are listed, and the basic concept of I/O function
library is introduced. To facilitate your skillful use of such instrument, please read carefully and follow this
manual in advance for correct operation.
SCPI (Standard Commands for Programmable Instruments) define the standards and methods for
remote control of the instrument, and are the remote control programming language for programmable
electronic test and measuring instruments. SCPI are based on the IEEE-488.2 standard and form.
Please refer to http://www.scpiconsortium.org for details. The manual describes the program control
commands of 1435 series signal generators in details.
The chapters of the programming manual include:
Remote Control
The methods for remote control of the instrument are summarized to make users get familiar with
remote control quickly. It is divided into three parts: remote control basics, introducing program
related concepts, software configuration, program port, SCPI, etc.; instrument port configuration
method, introducing the connection method and software configuration method for program ports of
1435 series signal generator; I/O function library, introducing the basic concept of instrument driver
and basic installation instructions of IVI-COM/IVI-C driver.
Program Control Commands
Common commands, instrument commands and compatible commands are introduced, and the
functions, parameters and examples of SCPI are described.
Programming Examples
The basic programming examples and advanced programming examples are provided in the way of
text description and example code, and the explanation is provided to make it convenient for users
to quickly master the remote control programming method of signal generator.
Error Description
Error description and method to obtain after-sales services are included.
Annexes
Necessary reference information related to program control of 1435 series signal generator is
provided, including zoom table of SCPI and zoom table of errors.

1. Manual Navigation
1.2 Related Documents
2
1.2 Related Documents
Documents of 1435 series signal generator include:
Quick Start Guide
User's Manual
Program Control Manual
Online Help
Quick Start Guide
This manual introduces the basic methods for configuration and start-up measurement of the instrument
to enable users to quickly understand the characteristics of the instrument, and master the basic settings
and basic operation methods. Main chapters include:
Get Prepared
Typical Applications
Get Help
User’s Manual
This manual describes the functions and operation methods of the instrument in detail, including
configuration, measurement, program control and maintenance, etc. The purpose is to guide users to
fully understand the functional characteristics of the product and master common testing methods of the
instrument. Main chapters include:
Manual Navigation
Overview
Quick Start
Operation Guide
Menus
Remote Control
Troubleshooting and Repair
Technical Indicators and Testing Methods
Annexes
Programming manual
This manual introduces remote programming basics, SCPI basics, SCPI, programming examples and
I/O driver function library in detail. The purpose is to guide users to quickly and comprehensively master
the program control commands and methods of the instrument. Main chapters include:
Remote Control
Program Control Commands
Programming Examples
Error Description
Annexes
Online Help
Online help is integrated in the instrument, providing fast text navigation help to make it convenient for
users in local and remote control operation. Both the hard keys on the front panel of the instrument or the
user interface tool bar offer corresponding shortcut keys to activate this function. Main chapters are
identical to those of the User's Manual.

2. Remote Control
2.1 Remote Control Basics
3
2. Remote Control
This chapter introduces the remote control basics, remote control interface and configuration methods of
1435 series signal generator, and briefly introduces the concept and classification of I/O instrument
driver library. The purpose is to facilitate users to start to achieve remote control. Specific contents
include:
Remote Control Basics···································································································· 3
Instrument Program Control Port and Configuration ···················································· 25
I/O Library······················································································································ 28
2.1 Remote Control Basics
Remote Control Interface································································································ 3
Message·························································································································· 6
SCPI Command··············································································································· 6
Command Sequence and Synchronization··································································· 14
Status Reporting System······························································································· 16
Programming Considerations························································································ 25
2.1.1 Program Control Interface
Instruments with remote control function generally support two kinds of remote control interface: LAN
and GPIB, and the type of port supported by the specific model of instrument is determined by the
function of the instrument.
The remote control interface and related VISA addressing string are described in the table below:
Table 2.1 Remote control interface type and VISAaddressing string
Remote control interface
VISA addressing string
Description
LAN
(Local Area Network)
VXI-11 protocol:
TCPIP::host_address[::LAN_device_name][::INSTR]
Raw socket protocol:
TCPIP::host_address::port::SOCKET
The controller realizes
remote control by
connecting the instrument
with the network port on
the rear panel of the
instrument.
For details of the protocol,
please refer to:
2.1.1.1 LAN Interface
GPIB
(IEC/IEEE Bus Interface)
GPIB::primary address[::INSTR] 4
The controller realizes
remote control by
connecting the instrument
with the port on the rear
panel of the instrument.
The bus interface
standard IEC 625.1/IEEE
418 is met.
For details, please refer
to:
2.1.1.2 GPIB Interface
LAN Interface··················································································································· 4
GPIB Interface················································································································· 5

2. Remote Control
2.1 Remote Control Basics
4
2.1.1.1 LAN Interface
The signal generator can be controlled remotely by computers in LAN 10Base-T or 100Base-T. Various
instruments are combined into a system in LAN and controlled uniformly by computers in it. In order to
realize remote control in LAN, the signal generator should be equipped with port connector, network card
and relevant network protocol in advance, and provided with relevant network services. Meanwhile, the
master computer in the network should also be equipped with instrument control software and VISA
library in advance. The three working modes of the network card are:
10Mbit/s Ethernet IEEE802.3;
100Mbit/s Ethernet IEEE802.3u;
1Gbit/s Ethernet IEEE802.3ab.
The master computer and the signal generator should be connected to the common TCP/IP protocol
network through the network port. The cable between the computer and the signal generator is a
commercial RJ45 cable (Category 5 cable with or without shielding). During data transmission, the
transmission speed of LAN is faster when data packet transmission is applied. Generally, the length of
the cable between the computer and the signal generator should not exceed 100m (100Base-T and
10Base-T). For more information about LAN communications, please refer to http://www.ieee.org.
Knowledges about the LAN interface are introduced below:
1) IP address
Physical connection of the network should be guaranteed for remote control on the signal generator via
the LAN. It is just required to set the address into the subnet of the host computer through the menu
"Local IP" of the signal generator. For example, if the IP address of the host computer is 192.168.12.0,
the IP address of the signal generator should be set to 192.168.12.XXX, where XXX is the value
between 1 and 255. The default network port number used by the signal generator for
communication is 5025.
When establishing a network connection, only the IP address is required. The VISA addressing string is
as follows:
TCPIP::host address[::LAN device name][::INSTR] or
TCPIP:: host address: port:: SOCKET
Where:
TCPIP represents the network protocol used;
host address represents the IP address or host name of the instrument, and is used for
identifying and controlling the controlled instrument;
LAN device name defines the handle number of the protocol and subset (optional);
—VXI-11 protocol is selected for device 0;
—More recent high speed LAN instrument protocol is selected for high speed LAN instrument
0;
INSTR represents the instrument resource type (optional);
port identifies the socket port number;
SOCKET represents the raw network socket resource class.
Example:
The IP address of the instrument is 192.1.2.3, and the effective resource string of the VXI-11
protocol is:
TCPIP::192.1.2.3::INSTR
To establish a raw socket connection, use:
TCPIP::192.1.2.3::5025::SOCKET

2. Remote Control
2.1 Remote Control Basics
5
Multi-instrument identification method in program system
If multiple instruments are connected in the network, the individual IP address and related resource
string are used to distinguish. The host computer applies its own VISA resource string for instrument
identification.
2) VXI-11 protocol
The VXI-11 standard is based on the ONC RPC (Open Network Computing Remote Procedure Call)
protocol, which is the network/transport layer of the TCP/IP protocol. The TCP/IP network protocol and
associated network services are pre-configured for communication. Such connection-oriented
communication, which follows the sequential exchange and can identify the interruption of the
connection, ensures no loss of information.
3) Socket communication
The TCP/IP protocol connects a signal source over a LAN socket in the network. As a basic method
used in computer network programming, the socket allows applications using different hardware and
operating systems to communicate over a network. With this method, two-way communication between
the signal generator and the computer is realized through port.
As a software class programmed specially, the socket defines the IP address, device port number and
other necessary information for network communication, and integrates some basic operations in
network programming. Sockets can be used after installing packaged libraries in the operating system.
Two commonly used socket libraries are the Berkeley socket library for UNIX and the Winsock library for
Windows.
Sockets in the signal generator are compatible with Berkeley sockets and Winsock through the
application program interface (API). In addition, it is compatible with the API of other standard sockets.
When SCPI are used to control the signal generator, the socket program established in the program
issues the command. Before using a LAN socket, the socket port number of the signal generator must
be set. The socket port number of the signal generator is 5025.
2.1.1.2 GPIB Interface
As an instrument remote control interface widely used at present, GPIB interface is connected to
different types of instruments through GPIB cable, so as to build a test system with the host computer. In
order to realize remote control, the host computer should be equipped with GPIB bus card, driver and
VISA library in advance. During communication, the host computer first addresses the controlled
instrument through the GPIB bus address. The user may set the GPIB address and ID query string, and
the GPIB communication language may be in the form of SCPI by default.
GPIB and its associated interface operations are defined and described in detail in ANSI/IEEE Standard
488.1-1987 and ANSI/IEEE Standard 488.2-1992. For details of the standards, please refer to the IEEE
website: http://www.ieee.org.http://www.ieee.org/
GPIB processes information in bytes, and the data transmission rate can reach 8MBps, which is
relatively fast. Since the data transmission rate is limited by the distance between the device/system and
the computer, the following points should be noted when connecting GPIB:
Up to 15 instruments may be built through GPIB interface.
The total length of the transmission cable should not be more than 15m or twice the number of
instruments in the system. Generally, the maximum length of transmission cables between
devices should not exceed 2m.
If multiple instruments are connected in parallel, a "live" cable is required.
The terminal of the IEC bus cable should be connected to the instrument or master computer.
Tip

2. Remote Control
2.1 Remote Control Basics
6
2.1.2 Message
The messages transmitted on the data cable are divided into the following two categories:
1) Interface message
During communication between the instrument and the host computer, the attention cable should be
pulled down first, and then the interface message will be transmitted to the instrument through the
data cable. Only instruments with GPIB bus function can send interface message.
2) Instrument message
Depending on the direction of transmission, instrument message can be divided into commands and
instrument responses. Unless otherwise stated, all remote control interfaces apply instrument
message in the same way.
a) Commands:
Commands (programming messages) are messages sent by the host computer to the
instrument for remote control of instrument functions and query of status information.
Commands are divided into the following two categories:
Based on the impact on the instrument:
-- setting commands: change the set state of the instrument, such as reset or setting
frequency.
-- query commands: query and return data, for example: identify the instrument or
query the parameter value. Query commands end with the suffix question mark.
Based on the definition in the standard:
-- common commands: with functions and syntax to be defined by IEEE488.2, they
are applicable to all types of instruments (if realized)
The purpose is for management of standard status register, reset and self-detection,
etc.
-- instrument control commands: instrument characteristic commands, used to realize
instrument functions, such as setting frequency.
The syntax also follows the specifications of SCPI.
b) Instrument responses:
Instrument responses (response message and service request) are the query result information
sent by the instrument to the computer. Such information includes measurement results,
instrument status, etc.
2.1.3 SCPI
Introduction to SCPI ······································································································ 6
Description of SCPI········································································································· 7
2.1.3.1 Introduction to SCPI Command
SCPI (Standard Commands for Programmable Instruments) are a command set for all instruments
established based on Standard IEEE488.2. The main purpose is to make the same function have the
same program command to achieve the universality of program control commands.
SCPI consist of a command header and one or more parameters. The command header is separated
from the parameters by spaces and contains one or more key fields. A command with direct suffix
question mark is a query command. Commands are divided into common commands and instrument
commands that have different syntactic structures. SCPI have the following characteristics:
1) Program control commands are oriented to test function rather than describing instrument
operation;
2) Program control commands reduce the repetition of similar test function realization process, and

2. Remote Control
2.1 Remote Control Basics
7
ensure the compatibility of programming.
3) Program messages are defined in layers that are hardware independent of the communication
physical layer.
4) Program control commands are independent of programming methods and languages. The test
program of SCPI is easy to transplant.
5) Program control commands are scalable and can adapt to different scale of measurement
control.
6) The extensibility of SCPI makes it a "living" standard.
If you are interested in learning more about SCPI, please refer to:
IEEE Standard 488.1-1987, IEEE Standard Digital Interface for
Programmable Instrumentation. New York, NY, 1998.
IEEE Standard 488.2-1987, IEEE Standard Codes, Formats, Protocols and Comment
Commands for Use withANSI/IEEE Std488.1-1987. New York, NY, 1998
Standard Commands for Programmable Instruments (SCPI) VERSION 1999.0.
For program command set, classification and description of 1435 series signal generator, please refer to:
1) "3. Program control commands" in this manual;
2) "Annex A Zoom Table of SCPI command" in User's Manual.
2.1.3.2 Description of SCPI
General Terms················································································································· 7
Command Type··············································································································· 8
Instrument Command Syntax·························································································· 8
Command Tree·············································································································· 10
Command Parameters and Responses········································································ 10
Number System of Commands····················································································· 13
Command Line Structure ······························································································ 14
Unit Description············································································································· 14
1) General Terms
The following terms apply to this section. To better understand the chapters, you shall understand the
exact definitions of the terms.
Controller
A controller is any computer used to communicate with the SCPI device. A controller may be a PC,
minicomputer, or a plug-in card on a cage. SomeAI devices can also be used as controllers.
Device
Adevice is any device that supports SCPI. Most of the devices are electronic measurement or excitation
devices that use GPIB interfaces for communication.
Program message
A program message is the combination of one or more SCPI that have been correctly formatted.
Program messages tell the devices how to measure and output the signals.
Response message
A response message is a set of data of specified SCPI formats. Response messages always come from
the devices to controllers or listening devices. Response messages tell the controllers about the internal
status or measured values of the devices.
Command

2. Remote Control
2.1 Remote Control Basics
8
A command is an instruction that satisfies the SCPI standard. The combination of commands controlling
the devices forms a message. In general, a command includes keywords, parameters, and punctuation.
Event command
Event-type program control commands cannot be queried. An event command generally has no
corresponding front panel key setting, and its function is to trigger an event at a specific time.
Query
A query is a special type of command. When a control device is queried, a response message
appropriate to the controller syntax requirements is returned. A query statement always ends with a
question mark.
2) Command Type
There are two types of SCPI: common commands and instrument commands. Figure 2.1 shows the
difference between the two commands. Common commands, defined by IEEE 488.2, are used to
manage macros and status registers and for synchronization and data storage. Because common
commands all start with an asterisk, they are easy to be recognized. For example, *IDN?, *OPC, *RST
are all common commands. Common commands are not part of any instrument commands, and the
instrument interprets them in the same way regardless of the current path setting of the commands.
Instrument commands are easy to be recognized because they contain a colon (:).A colon is used in the
beginning of an expression or between two keywords, for example: FREQuency[:CW? ]. According to
the internal function module of the instrument, instrument commands are divided into sub-sets of
corresponding subsystem commands. For example, the power subsystem (:POWer) contains
power-related commands, while the status subsystem (:STATus) contains commands for the status
control register.
Figure 2.1 Types of SCPI
3) Instrument Command Syntax
A typical command consists of a keyword prefixed with a colon. The keyword is followed by parameters.
Here is an example of a syntax statement.
[:SOURce]:POWer[:LEVel] MAXimum|MINimum
In the example above, [:LEVel] in the command immediately follows :POWer without any space.
MINimum|MAXimum immediately following [:LEVel] is the parameter. There is a space between the
command and the parameter. Other parts of the syntax expression are described in Table 2.2 and Table
2.3.
SCPI
Common
commands
Instrument
commands

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2.1 Remote Control Basics
9
Table 2.2 Special characters in command syntax
Symbol
Meaning
Example
|
The vertical bar between the keyword and the
parameter represents multiple options.
[:SOURce]:AM:
SOURce EXTernal|INTernal
EXTernal and INTernal are optional
[]
A square bracket indicates that the contained keyword
or parameter is optional when forming a command. The
command will be executed even when such implied
keyword or parameter is ignored.
[:SOURce]:AM[:DEPTh]:EXPon
ential?
SOURce and DEPTh are optional.
< >
The part in angle brackets indicates that the command
is not used in the literal sense. They represent the part
that must be contained.
[:SOURce]:FREQ:STOP
<val><uint>
In the command, <val> and <uint>
must be replaced with actual
frequency and unit.
For example: :FREQ:STOP 3.5GHz
{ }
The part in braces indicates that the parameter is
optional.
[:SOURce]:LIST:POWer
<val>{,<val>}
For example: LIST:POWer 5
Table 2.3 Command syntax
Characters, keywords, and syntax
Example
Uppercase character represents the minimum set of
characters required to execute the command.
[:SOURce]:FREQuency[:CW]?,
FREQ is the short format part of the
command.
Lowercase character of the command is optional; such
flexible format is called "flexible listening". Please refer to
"Command Parameters and Responses" for more
information.
:FREQuency
:FREQ,:FREQuency
or :FREQUENCY
Either of them is correct.
When a colon is between two command mnemonics, it will
move the current path down a level in the command tree.
Please refer to the command path of "Command Tree" for
more information.
:TRIGger[:SEQuence]:SOURce?
TRIGger is the top-level keyword for the
command.
If the command contains more than one parameter,
adjacent parameters are separated by commas. The
parameter is not part of the command path, so it does not
affect the path layer.
[:SOURce]:LIST:DWELl <val>{,<val>}
A semicolon separates two adjacent commands without
affecting the current command path.
:FREQ 2.5GHZ; :POW 10DBM
Blank characters, such as <space> or <tab>, are usually
ignored as long as they do not appear between
or within keywords. However, you must use blank
characters to separate commands and parameters
without affecting the current path.
:FREQ uency or :POWer :LEVel6.2 is not
allowed;
:LEVel and 6.2 must be separated by a
space; namely, :POWer:LEVel 6.2.

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10
4) Command Tree
Most remote control programs apply instrument commands. When parsing such commands, SCPI apply
a file system-like structure called command tree, as shown in Figure 2.2:
Figure 2.2 Simplified command tree
The top command is the root command, or "root" for short. When a command is parsed, follow a specific
path to the next level of command according to the tree structure. For example,
in :POWer:ALC:SOURce?, :POWer stands for AA, :ALC stands for BB, :SOURce stands for GG, and the
entire command path is (:AA:BB:GG).
A software module in instrument software - command interpreter, is responsible for parsing each
received SCPI. The command interpreter breaks commands into individual command elements by using
a series of rules that distinguish the path of the command tree.After parsing the current command, keep
the current command path unchanged. The advantage of this is to parse subsequent commands more
quickly and efficiently since that the same command keyword may appear in different paths. After
starting or *RST (resetting) the instrument, reset the current command path to root.
5) Command Parameters and Responses
SCPI define different data formats in the use of program and response messages to comply with the
principles of "flexible listening" and "precise speaking". For more information, please refer to
IEEE488.2. "Flexible listening" means that the formats of the commands and parameters are flexible.
For example, in setting frequency reference state command of signal
generator: :FREQuency:REFerence:STATe ON|OFF|1|0, the following command formats show that the
setting frequency reference function is ON:
:FREQuency:REFerence:STATe ON, :FREQuency:REFerence:STATe 1,
:FREQ:REF:STAT ON, :FREQ:REF:STAT 1.
Each parameter type has one or more corresponding response data types. During query, a data type will
be returned for a numerical parameter, and the response data is precise and strict, known as "precise
speaking."
For example, during query of the power state (:POWer:ALC:STATe?), when it is ON, the response data
returned is always 1 during query, regardless of whether the previously sent setting command
is :POWer:ALC:STATe 1 or :POWer:ALC:STATe ON.
AA
BB
CC
DD
EE
FF
GG
HH
JJ
Root

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11
Table 2.4 Parameter and response types of SCPI
Parameter type
Response data type
Numerical
Real number or integer
Extended numerical
Integer
Discrete
Discrete
Boolean
Digital boolean
String
String
Blocks
Finite-length blocks
Infinite-length blocks
Non-decimal numeric types
Hexadecimal
Octal
Binary
Numerical parameters
Numerical parameters can be used in both instrument commands and common commands. A numeric
parameter receives all the usual decimal counting methods, including signs, decimals, and scientific
notation. If a device only accepts a specified numeric type, such as an integer, it will automatically round
up the received numeric parameters.
Examples of numeric parameters:
0 No decimal point
100 Optional decimal point
1.23 Signed bit
4.56e<space>3 Index mark e can be followed by a space
-7.89E-01 Index marker e can be uppercase or lowercase
+256 Positive lookahead allowed
5 Decimal points can be used first
Extended numerical parameters
Most measurements related to instrument commands use extended numeric parameters to specify
physical quantities. Extended numerical parameters receive all numeric parameters and additional
special values. All the extended numeric parameters receive MAXimum and MINimum as parameter
values. Whether other special values, such as UP and DOWN, will be received is determined by the
ability of the instrument to parse.All effective parameters will be listed in the table of SCPI.
Note: Extended numeric arguments do not apply to common commands or STATus subsystem
commands.
Examples of extended numeric parameters:
101 Numeric parameter
1.2GHz GHz can be used as an index (E009)
200MHz MHz can be used as an index (E006)
-100mV -100 millivolts
10DEG 10 degrees
MAXimum Maximum effective setting
MINimum Minimum effective setting
UP Increase by a step
DOWN Reduce by a step

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Discrete parameters
When the number of parameter values to be set are finite, they are identified by discrete parameters.
Discrete parameters use mnemonics to represent each valid setting. Like program command
mnemonics, discrete parameter mnemonics have two formats, long and short, and allow for mixture of
upper and lower cases.
In the following examples, discrete parameters and commands are used together.
:TRIGger[:SEQuence]:SOURce BUS|IMMediate|EXTernal
BUS GPIB, LAN, RS-232 trigger
IMMediate Trigger immediately
EXTernal Trigger externally
Boolean parameters
A Boolean parameter represents a true or false binary condition, which can only have four possible
values.
Examples of Boolean parameters
ON Logically true
OFF Logically false
1 Logically true
0 Logically false
String parameters
String parameters allow ASCII strings to be sent as parameters. Single quotes and double quotes are
used as separators.
Examples of string parameters
‗This is Valid‘ ―This is also Valid‖ ‗SO IS THIS‘
Real response data
Most of the test data are of real number type, and their formats can be basic decimal notation or
scientific notation, which are supported by most advanced programming languages.
Examples of real response data:
1.23E+0
-1.0E+2
+1.0E+2
0.5E+0
0.23
-100.0
+100.0
0.5
Integer response data
An integer response data is a decimal expression of an integer value containing signed bit. When
querying the status register, most of the response data returned are of integer type.