Ametek LX series Operating and maintenance manual

Lx \ Ls Series
AC Power Source
Programming Manual
Contact Information
Telephone: [phone] (toll free in North America)
858 450 0085 (direct)
Fax: [phone]
Email:
Domestic Sales: [e-mail]
International Sales: [e-mail]
Customer Service: [email protected]
Web: www.programmablepower.com
March 2011 Document No. 7004-961 Rev. J

Refers to Lx and Ls Series AC Power Source/Analyzers
Models:
Single chassis: 3000Lx, 4500Lx, 6000Lx
Multiple chassis: 9000Lx/2, 12000Lx/2, 13500Lx/3, 18000Lx/3
Single chassis: 3000Ls, 4500Ls, 6000Ls
Multiple chassis: 9000Ls/2, 12000Ls/2, 13500Ls/3, 18000Ls/3
Manual revision: J, March 2011

i
About AMETEK
AMETEK Programmable Power, Inc., a Division of AMETEK, Inc., is a global leader in the design
and manufacture of precision, programmable power supplies for R&D, test and measurement,
process control, power bus simulation and power conditioning applications across diverse
industrial segments. From bench top supplies to rack-mounted industrial power subsystems,
AMETEK Programmable Power is the proud manufacturer of Elgar, Sorensen, California
Instruments and Power Ten brand power supplies.
AMETEK, Inc. is a leading global manufacturer of electronic instruments and electromechanical
devices with annualized sales of $2.5 billion. The Company has over 11,000 colleagues working
at more than 80 manufacturing facilities and more than 80 sales and service centers in the United
States and around the world.
Trademarks
AMETEK is a registered trademark of AMETEK, Inc.
Other trademarks, registered trademarks, and product names are the property of their respective
owners and are used herein for identification purposes only.
Notice of Copyright
Lx\Ls Series, AC Power Source, Programming Manual © 2010 AMETEK Programmable Power,
Inc. All rights reserved.
Exclusion for Documentation
UNLESS SPECIFICALLY AGREED TO IN WRITING, AMETEK PROGRAMMABLE POWER, INC.
(“AMETEK”):
(a) MAKES NO WARRANTY AS TO THE ACCURACY, SUFFICIENCY OR SUITABILITY OF ANY
TECHNICAL OR OTHER INFORMATION PROVIDED IN ITS MANUALS OR OTHER
DOCUMENTATION.
(b) ASSUMES NO RESPONSIBILITY OR LIABILITY FOR LOSSES, DAMAGES, COSTS OR
EXPENSES, WHETHER SPECIAL, DIRECT, INDIRECT, CONSEQUENTIAL OR INCIDENTAL,
WHICH MIGHT ARISE OUT OF THE USE OF SUCH INFORMATION. THE USE OF ANY SUCH
INFORMATION WILL BE ENTIRELY AT THE USER’S RISK, AND
(c) REMINDS YOU THAT IF THIS MANUAL IS IN ANY LANGUAGE OTHER THAN ENGLISH,
ALTHOUGH STEPS HAVE BEEN TAKEN TO MAINTAIN THE ACCURACY OF THE
TRANSLATION, THE ACCURACY CANNOT BE GUARANTEED. APPROVED AMETEK CONTENT
IS CONTAINED WITH THE ENGLISH LANGUAGE VERSION, WHICH IS POSTED AT
WWW.PROGRAMMABLEPOWER.COM.
Date and Revision
March 2011 Revision J
Part Number
7004-961
Contact Information
Telephone: [phone] (toll free in North America)
858 450 0085 (direct)
Fax: [phone]
Email: [e-mail]
[e-mail]
Web: www.programmablepower.com

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Important Safety Instructions
Before applying power to the system, verify that your product is configured properly for your
particular application.
WARNING
Hazardous voltages may be present when covers are removed. Qualified
personnel must use extreme caution when servicing this equipment.
Circuit boards, test points, and output voltages also may be floating above
(below) chassis ground.
WARNING
The equipment used contains ESD sensitive ports. When installing
equipment, follow ESD Safety Procedures. Electrostatic discharges might
cause damage to the equipment.
Only qualified personnel who deal with attendant hazards in power supplies, are allowed to perform
installation and servicing.
Ensure that the AC power line ground is connected properly to the Power Rack input connector or
chassis. Similarly, other power ground lines including those to application and maintenance
equipment must be grounded properly for both personnel and equipment safety.
Always ensure that facility AC input power is de-energized prior to connecting or disconnecting any
cable.
In normal operation, the operator does not have access to hazardous voltages within the chassis.
However, depending on the user’s application configuration, HIGH VOLTAGES HAZARDOUS TO
HUMAN SAFETY may be normally generated on the output terminals. The customer/user must
ensure that the output power lines are labeled properly as to the safety hazards and that any
inadvertent contact with hazardous voltages is eliminated.
Guard against risks of electrical shock during open cover checks by not touching any portion of the
electrical circuits. Even when power is off, capacitors may retain an electrical charge. Use safety
glasses during open cover checks to avoid personal injury by any sudden component failure.
Neither AMETEK Programmable Power Inc., San Diego, California, USA, nor any of the subsidiary
sales organizations can accept any responsibility for personnel, material or inconsequential injury,
loss or damage that results from improper use of the equipment and accessories.
SAFETY SYMBOLS

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Product Family: Lx \ Ls Series
Warranty Period: One Year
WARRANTY TERMS
AMETEK Programmable Power, Inc. (“AMETEK”), provides this written warranty covering the
Product stated above, and if the Buyer discovers and notifies AMETEK in writing of any defect in
material or workmanship within the applicable warranty period stated above, then AMETEK may,
at its option: repair or replace the Product; or issue a credit note for the defective Product; or
provide the Buyer with replacement parts for the Product.
The Buyer will, at its expense, return the defective Product or parts thereof to AMETEK in
accordance with the return procedure specified below. AMETEK will, at its expense, deliver the
repaired or replaced Product or parts to the Buyer. Any warranty of AMETEK will not apply if the
Buyer is in default under the Purchase Order Agreement or where the Product or any part
thereof:
is damaged by misuse, accident, negligence or failure to maintain the same as
specified or required by AMETEK;
is damaged by modifications, alterations or attachments thereto which are not
authorized by AMETEK;
is installed or operated contrary to the instructions of AMETEK;
is opened, modified or disassembled in any way without AMETEK’s consent; or
is used in combination with items, articles or materials not authorized by AMETEK.
The Buyer may not assert any claim that the Products are not in conformity with any warranty
until the Buyer has made all payments to AMETEK provided for in the Purchase Order Agreement.
PRODUCT RETURN PROCEDURE
1. Request a Return Material Authorization (RMA) number from the repair facility (must be
done in the country in which it was purchased):
In the USA, contact the AMETEK Repair Department prior to the return of the
product to AMETEK for repair:
Telephone: [phone], ext. 2295 or ext. 2463 (toll free North America)
858-450-0085, ext. 2295 or ext. 2463 (direct)
Outside the United States, contact the nearest Authorized Service Center
(ASC). A full listing can be found either through your local distributor or our
website, www.programmablepower.com, by clicking Support and going to the
Service Centers tab.
2. When requesting an RMA, have the following information ready:
Model number
Serial number
Description of the problem
NOTE: Unauthorized returns will not be accepted and will be returned at the shipper’s expense.
NOTE: A returned product found upon inspection by AMETEK, to be in specification is subject to
an evaluation fee and applicable freight charges.

Programming Manual Lx \ Ls Series
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Table of Contents
1. Introduction..........................................................................................................................................8
1.1 Documentation Summary...............................................................................................................8
1.2 Lx Series and Ls Series Differences...............................................................................................9
1.3 Manual organization and format .....................................................................................................9
1.4 Introduction to Programming ........................................................................................................10
2. Introduction to SCPI ..........................................................................................................................11
2.1 Conventions Used in This Manual................................................................................................11
2.2 The SCPI Commands and Messages ..........................................................................................11
2.3 Using Queries...............................................................................................................................14
2.4 Coupled Commands.....................................................................................................................14
2.5 Structure of a SCPI Message.......................................................................................................14
2.6 SCPI Data Formats.......................................................................................................................17
3. System Considerations.....................................................................................................................19
3.1 Assigning the IEEE-488 Address in Programs.............................................................................19
3.2 Instrument Drivers and Application Software................................................................................19
4. SCPI Command Reference................................................................................................................20
4.1 Introduction...................................................................................................................................20
4.2 Subsystem Commands.................................................................................................................21
4.3 Calibration Subsystem..................................................................................................................22
4.4 Diagnostic Subsystem ..................................................................................................................24
4.5 Instrument Subsystem..................................................................................................................25
4.6 Limit Subsystem ...........................................................................................................................26
4.7 Array Measurement Subsystem ...................................................................................................28
4.8 Current Measurement Subsystem................................................................................................33
4.9 Frequency Measurement Subsystem...........................................................................................38
4.10 Power Measurement Subsystem..................................................................................................39
4.11 Voltage Measurement Subsystem................................................................................................41
4.12 Output Subsystem ........................................................................................................................44
4.13 Power On Subsystem...................................................................................................................48
4.14 Sense Subsystem - Sweep...........................................................................................................49
4.15 Source Subsystem - Current ........................................................................................................51
4.16 Source Subsystem - Frequency....................................................................................................53
4.17 Source Subsystem - Function.......................................................................................................56
4.18 Source Subsystem - List...............................................................................................................59
4.19 Source Subsystem - Phase ..........................................................................................................65
4.20 Source Subsystem - Pulse ...........................................................................................................67
4.21 Source Subsystem - Voltage ........................................................................................................70
4.22 Status Subsystem Commands .....................................................................................................76
4.23 System Commands ......................................................................................................................83
4.24 Trace Subsystem Commands ......................................................................................................86
4.25 Trigger Subsystem........................................................................................................................88

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5. Common Commands.........................................................................................................................93
5.1 *CLS..............................................................................................................................................94
5.2 *ESR?...........................................................................................................................................94
5.3 *IDN? ............................................................................................................................................95
5.4 *OPC.............................................................................................................................................95
5.5 *OPT?...........................................................................................................................................95
5.6 *PSC.............................................................................................................................................95
5.7 *RCL .............................................................................................................................................96
5.8 *RST .............................................................................................................................................97
5.9 *SAV .............................................................................................................................................98
5.10 *SRE.............................................................................................................................................98
5.11 *STB?............................................................................................................................................98
5.12 *TRG.............................................................................................................................................99
5.13 *TST?............................................................................................................................................99
5.14 *WAI............................................................................................................................................100
6. Programming Examples..................................................................................................................101
6.1 Introduction.................................................................................................................................101
6.2 Programming the Output ............................................................................................................101
6.3 Coupled Commands...................................................................................................................105
6.4 Programming Output Transients ................................................................................................106
6.5 Step and Pulse Transients..........................................................................................................107
6.6 List Transients ............................................................................................................................109
6.7 Triggering Output Changes ........................................................................................................110
6.8 Making Measurements ...............................................................................................................114
6.9 Controlling the Instantaneous Voltage and Current Data Buffers...............................................119
6.10 Downloading Arbitrary Waveforms.............................................................................................122
6.11 Command Processing Times .....................................................................................................123
7. Programming the Status and Event Registers .............................................................................124
7.1 Power-On Conditions..................................................................................................................124
7.2 Operation Status Group..............................................................................................................124
7.3 Questionable Status Group ........................................................................................................127
7.4 Questionable Instrument Isummary Status Group .....................................................................128
7.5 Standard Event Status Group.....................................................................................................129
7.6 Status Byte Register ...................................................................................................................130
7.7 Examples....................................................................................................................................131
7.8 Remote Inhibit and Discrete Fault Indicator................................................................................134
7.9 SCPI Command Completion.......................................................................................................135
8. Option Commands...........................................................................................................................136
8.1 Introduction.................................................................................................................................136
8.2 APE Command Language (Abbreviated Plain English)..............................................................137
8.3 RTCA/DO-160D (-160)...............................................................................................................156
8.4 MIL-STD 704 Rev D - F (-704) ...................................................................................................163
8.5 MIL-STD 704 Rev A - F (-704F) .................................................................................................169
Appendix A: SCPI Command tree..........................................................................................................183
Appendix B: SCPI Conformance Information....................................................................................... 187
Appendix C: Error Messages .................................................................................................................190
Appendix D: iL Series / HP6834B Compatability.................................................................................197
Index.........................................................................................................................................................198

Programming Manual Lx \ Ls Series
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Table of Figures
Figure 2-1: Partial Command Tree..............................................................................................................12
Figure 2-2: Command Message Structure..................................................................................................15
Figure 6-1: Model of transient system.......................................................................................................107
Figure 6-2: Model of output trigger system................................................................................................111
Figure 6-3: Model of Measurement triggers..............................................................................................117
Figure 6-4: Pre- and Post Event Triggering...............................................................................................121
Figure 7-1: Status Register Model.............................................................................................................125
Figure 7-2: SMA Connector Trigger Model...............................................................................................133
Figure 8-1: APE Command Tree...............................................................................................................142
Table of Tables
Table 2-1: Command parameters Suffixes and Multipliers.........................................................................17
Table 4-1: PULSe:HOLD = WIDTh parameters.........................................................................................68
Table 4-2: PULSe:HOLD = DCYCle parameters ........................................................................................68
Table 4-3: Bit Configuration of Status Operation Registers........................................................................77
Table 4-4: Bit Configuration of Questionable Registers..............................................................................78
Table 4-5: Bit Configuration of Questionable Instrument Summary Registers ...........................................80
Table 5-1: Bit Configuration of Standard Event Status Enable Register.....................................................94
Table 5-2 : factory-defined *RST states......................................................................................................97
Table 5-3: Bit Configuration of Status Byte Register...................................................................................99
Table 6-1: Command Processing Times...................................................................................................123
Table 7-1: Operation Status registers .......................................................................................................124
Table 7-2: Bit Configurations of Status Registers.....................................................................................126
Table 7-3: Questionable Status registers..................................................................................................127
Table 7-4: Questionable Instrument Isummary Status registers...............................................................128
Table 8-1: APE to SCPI mode change commands...................................................................................137
Table 8-2: APE versus SCPI equivalent power initialization commands...................................................139
Table 8-3: APE language syntax program headers ..................................................................................144
Table 8-4: APE Language TLK Arguments...............................................................................................146
Table 8-5: Example TALK responses for 3 phase systems......................................................................152
Table 8-6: APE Status Byte Error Codes ..................................................................................................154
Table 8-7: MS704 Steady state frequency by group.................................................................................172
Table 8-8: SCPI error codes and messages.............................................................................................195

Programming Manual Lx \ Ls Series
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1. Introduction
This manual contains programming information for the Lx Series and Ls Series AC
source/Analyzers. The expression "AC source" as used in the manual also applies to the same
series. You will find the following information in the rest of this manual:
Chapter 2 Introduction to SCPI
Chapter 3 System Considerations
Chapter 4 SCPI Command Reference
Chapter 5 Common Commands
Chapter 6 Programming Examples
Chapter 7 Programming the Status and Event Registers
Chapter 8 Options
Appendix A SCPI command tree
Appendix B SCPI conformance information
Appendix C Error messages
1.1 Documentation Summary
The following document is related to this Programming Manual and may have additional helpful
information for using the AC source.
User's Manual. P/N 7004-960 Includes specifications and supplemental characteristics, how
to use the front panel, how to connect to the instrument, and calibration procedures.
1.1.1 External References
SCPI References
The following documents will assist you with programming in SCPI:
Beginner's Manual to SCPI. Highly recommended for anyone who has not had previous
experience programming with SCPI.
Controller programming manuals: consult the documentation supplied with the IEEE-488
controller or IEEE-488 PC plug in card for information concerning general IEEE-488.2
conventions and concepts.
The following are two formal documents concerning the IEEE-488 interface:
ANSI/IEEE Std. 488.1-1987 IEEE Standard Digital Interface for Programmable
Instrumentation. Defines the technical details of the IEEE-488 interface. While much of the
information is beyond the need of most programmers, it can serve to clarify terms used in this
manual and in related documents.
ANSI/IEEE Std. 488.2-1987 IEEE Standard Codes, Formats, Protocols, and Common
Commands. Recommended as a reference only if you intend to do fairly sophisticated
programming. Helpful for finding precise definitions of certain types of SCPI message
formats, data types, or common commands.
The above two documents are available from the IEEE (Institute of Electrical and Electronics
Engineers), 345 East 47th Street, New York, NY 10017, USA or via the web at www.ieee.org .

Programming Manual Lx \ Ls Series
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1.2 Lx Series and Ls Series Differences
The Lx Series and Ls Series of AC power sources are both based on the same AC power source
hardware platform and share many common components. The differences are primarily in
configuration and options. This manual covers both model series. Some commands listed may
not apply to Ls Series AC sources without the –ADV option and / or –MODE option.
1.2.1 Firmware differences
The Lx Series is fully featured and supports all commands listed in the programming manual.
The Ls Series provides most basic functions in its standard configurations. More advanced
features can be added by specifying the –ADV (advanced) option. If the –ADV option is installed,
all commands listed in this programming manual are supported. If not, commands related to
arbitrary waveforms and harmonic analysis measurements are not supported and will generate a
“-113 Syntax Error” message.
1.2.2 Hardware differences
In addition to the firmware differences described, the following hardware differences exist
between the standard Lx Ac source and the Ls AC source.
Lx has a 150V / 300 V rms output range pair. Optional ranges of 135/270 (-HV option)
and 200/400 (-EHV option) are available at time of order.
Ls has a 135 V / 270 V rms output range pair. Optional ranges of 156/312 (-HV option)
and 200/400 (-EHV option) are available at time of order.
The Lx rear panel connector labeling is compliant with the California Instruments iL Series
which it replaces and the HP/Agilent model 6834B.
The Ls rear panel connector labeling is compliant with the California Instruments L Series.
The Lx Series comes standard with both GPIB and RS232C interfaces.
The Ls Series comes standard with an RS232C only, An optional GPIB interface (-GPIB
option) is available.
Note: Both interfaces use the SCPI command syntax as described in the programming manual.
The Lx Series provides both three phase and single phase output modes which can be
selected from the front panel or over the bus.
The Ls Series provides either three phase (-3 models) or single phase (-1 models).
Three phase Ls Series sources may optionally be equipped with the –MODE option which
provides the same phase mode switching as the Lx Series.
1.3 Manual organization and format
All user documentation for California Instruments power sources is provided on CDROM in
electronic format. (Adobe Portable Document Format) The required Adobe PDF viewer is
supplied on the same CDROM. This manual may be printed for personal use if a hardcopy is
desired. To request a hardcopy from California Instruments, contact customer service at
[email protected]. There will be an additional charge for printed manuals.
This manual contains sections on programming the Lx or Ls Series over the bus. The Lx Series is
equipped with both GPIB and RS232C interfaces. The Ls Series is equipped with a RS232C
interface. An optional GPIB interface can be specified at the time of order. Refer to the Lx / Ls

Programming Manual Lx \ Ls Series
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Series User manual for information on using the remote control interface and command syntax.
The user manual (P/N 7004-960) is provided on the same CDROM as this user manual.
California Instruments may make updated versions of this manual available from time to time in
electronic format through it‟s website. To obtain an updated manual revision if available, check the
California Instruments Manual download page at www.calinst.com. You need to register as a
customer to obtain free access to manual and software downloads.
1.4 Introduction to Programming
This section provides some general information regarding programming IEEE-488 bus
instrumentation.
1.4.1 IEEE-488 Capabilities of the AC source
All AC source functions except for setting the IEEE-488 address are programmable over the
IEEE-488. The IEEE 488.2 capabilities of the AC source are listed in Chapter 2 of the User's
Manual. The Ls Series requires the –GPIB option.
1.4.2 IEEE-488 Address
The AC source operates from an IEEE-488 address that is set from the front panel. To set the
IEEE-488 address, press the Menu key on the front panel repeatedly until the CONFIGURATION
entry is shown on the LCD display.
Move the indicator on the right hand side of the display to point to CONFIGURATION and press
the ENTER key.
This will display the IEEE ADRRESS currently set. To change the address, use the Voltage knob
to increment or decrement the value. Press the ENTER key to confirm your selection.
1.4.3 RS232C Capabilities of the AC source
All AC source functions are programmable over the RS232C interface. The RS232C capabilities
of the AC source are listed in Chapter 2 of the User's Manual. Some capabilities support on the
GPIB interface such as ATN, GET and SRQ interrupts do not apply to the RS232C interface.
Baudrates from 9600 to 115200 are supported.
The RS232C interface may be used to install updated firmware for the Lx / Ls controller if needed.
Firmware updates and a Flash Loader utility program and instructions are available from the
California Instruments website for this purpose. (www.calinst.com )

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2. Introduction to SCPI
SCPI (Standard Commands for Programmable Instruments) is a programming language for
controlling instrument functions over the IEEE-488. SCPI is layered on top of the hardware-portion
of IEEE 488.2. The same SCPI commands and parameters control the same functions in different
classes of instruments.
2.1 Conventions Used in This Manual
Angle brackets <> Items within angle brackets are parameter abbreviations. For
example, <NR1> indicates a specific form of numerical data.
Vertical bar | Vertical bars separate alternative parameters. For example,
NORM | TEXT indicates that either "TEXT" or "NORM" can be used as a
parameter.
Square Brackets [] Items within square brackets are optional. The representation
[SOURce:]LIST means that SOURce: may be omitted.
Braces {} Braces indicate parameters that may be repeated zero or more
times. It is used especially for showing arrays. The notation <A> <,B>
shows that parameter "A" must be entered, while parameter "B" may be
omitted or may be entered one or more times.
2.2 The SCPI Commands and Messages
2.2.1 Types of SCPI Commands
SCPI has two types of commands, common and subsystem.
Common commands generally are not related to specific operation but to
controlling overall AC source functions, such as reset, status, and synchronization. All common
commands consist of a three-letter mnemonic preceded by an
asterisk: *RST, *IDN?, *SRE 8
Subsystem commands perform specific AC source functions. They are organized
into an inverted tree structure with the "root" at the top. Some are
single commands while others are grouped within specific
subsystems.
Refer to appendix A for the AC source SCPI tree structure.
2.2.2 Types of SCPI Messages
There are two types of SCPI messages, program and response.
A program message consists of one or more properly formatted SCPI commands sent from
the controller to the AC source. The message, which may be sent at any time, requests the
AC source to perform some action.
A response message consists of data in a specific SCPI format sent from the AC source to
the controller. The AC source sends the message only when commanded by a program
message called a "query."

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2.2.3 The SCPI Command Tree
As previously explained, the basic SCPI communication method involves sending one or more
properly formatted commands from the SCPI command tree to the instrument as program
messages. Figure 2-1 shows a portion of a subsystem command tree, from which you access the
commands located along the various paths (you can see the complete tree in appendix A).
Root
:OUTPut
:COUPling
:DFI
:PROTection
:OPERation
:SOURce
:CLEar
:DELay
:STATus
[:STATe]
[:STATe]
[:EVEN]?
:CONDition?
Figure 2-1: Partial Command Tree
The Root Level
Note the location of the ROOT node at the top of the tree. Commands at the root level are at the
top level of the command tree. The SCPI interface is at this location when:
the AC source is powered on
a device clear (DCL) is sent to the AC source
the SCPI interface encounters a message terminator (LF)
the SCPI interface encounters a root specifier (:)
Active Header Path
In order to properly traverse the command tree, you must understand the concept of the active
header path. When the AC source is turned on (or under any of the other conditions listed above),
the active path is at the root. That means the SCPI interface is ready to accept any command at
the root level, such as OUTPut or STATe.
If you enter OUTPut, the active header path moves one colon to the right. The interface is now
ready to accept :STATe, :COUPling,:DFI, or :PROTection as the next header. You must include
the colon, because it is required between headers.
If you now enter :PROTection, the active path again moves one colon to the right. The interface is
now ready to accept either :CLEar or :DELay as the next header.
If you now enter :CLEar, you have reached the end of the command string. The active header
path remains at :CLEar. If you wished, you could have entered :CLEar;DELay 20 and it would be
accepted as a compound message consisting of:
1. OUTPut:PROTection:CLEAr and

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2. OUTPut:PROTection:DELay 20.
The entire message would be:
OUTPut:PROTection:CLEar;DELay 20
The message terminator after DELay 20 returns the path to the root.
The Effect of Optional Headers
If a command includes optional headers, the interface assumes they are there. For example, if
you enter OUTPut OFF, the interface recognizes it as OUTPut:STATe OFF. This returns the
active path to the root (:OUTPut). But if you enter OUTPut:STATe OFF, then the active path
remains at :STATe. This allows you to send
OUTPut:STATe OFF;PROTection:CLEar
in one message. If you tried to send
OUTPut OFF;PROTection:CLEar
the header path would return to :OUTPut instead of :PROTection.
The optional header [SOURce] precedes the current, frequency, function, phase, pulse, list, and
voltage subsystems. This effectively makes :CURRent,:FREQuency, :FUNCtion, :PHASe,
:PULse, :LIST, and :VOLTage root-level commands.
Moving Among Subsystems
In order to combine commands from different subsystems, you need to be able to restore the
active path to the root. You do this with the root specifier (:). For example, you could clear the
output protection and check the status of the Operation Condition register as follows:
OUTPut:PROTection:CLEAr
STATus:OPERation:CONDition?
Because the root specifier resets the command parser to the root, you can use the root specifier
and do the same thing in one message:
OUTPut:PROTection:CLEAr;:STATus:OPERation:CONDition?
The following message shows how to combine commands from different subsystems as well as
within the same subsystem:
VOLTage:LEVel 70;PROTection 80;:CURRent:LEVel 3;PROTection:STATe ON
Note the use of the optional header LEVel to maintain the correct path within the voltage and
current subsystems and the use of the root specifier to move between subsystems.
Note: The "Enhanced Tree Walking Implementation" given in appendix A of the IEEE 488.2
standard is not implemented in the AC source.
Including Common Commands
You can combine common commands with system commands in the same message. Treat the
common command as a message unit by separating it with a semicolon (the message unit
separator). Common commands do not affect the active header path; you may insert them
anywhere in the message.
VOLTage:TRIGger 7.5;INITialize;*TRG
OUTPut OFF;*RCL 2;OUTPut ON

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2.3 Using Queries
Observe the following precautions with queries:
Set up the proper number of variables for the returned data.
Read back all the results of a query before sending another command to the AC source.
Otherwise a Query Interrupted error will occur and the unreturned data will be lost.
2.4 Coupled Commands
When commands are coupled it means that the value sent by one command is affected by the
settings of the other commands. The following commands are coupled in the AC source:
the voltage and function shape commands
the step, pulse, and list commands that control output voltages and function shapes
the pulse commands that program the width, duty cycle, period, and the hold parameter
the voltage range and current limit commands
As explained later in chapter 4, the order in which data is sent by these coupled commands can
be important when more than one parameter is changed.
2.5 Structure of a SCPI Message
SCPI messages consist of one or more message units ending in a message terminator. The
terminator is not part of the syntax, but implicit in the way your programming language indicates
the end of a line (such as a newline or end-of-line character).
2.5.1 The Message Unit
The simplest SCPI command is a single message unit consisting of a command header (or
keyword) followed by a message terminator.
ABORt<newline>
VOLTage?<newline>
The message unit may include a parameter after the header. The parameter usually is
numeric, but it can be a string:
VOLTage 20<newline>
VOLTage MAX<newline>
2.5.2 Combining Message Units
The following command message is briefly described here, with details in subsequent paragraphs.

Programming Manual Lx \ Ls Series
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VOLT : LEV 80 ; PROT 88 ; : CURR? <NL>
Headers
Data
Message UnitQuery Indicator
Header
Separator
Message
Unit
Separator Root Specifier
Message
Terminator
Figure 2-2: Command Message Structure
The basic parts of the above message are:
Message Component Example
Headers VOLT LEV PROT CURR
Header Separator The colon in VOLT:LEV
Data 80 88
Data Separator The space in VOLT 80 and PROT 88
Message Units VOLT:LEV 80 PROT 88 CURR?
Message Unit Separator The semicolons in VOLT:LEV 80; and PROT 88;
Root Specifier The colon in PROT 88;:CURR?
Query Indicator The question mark in CURR?
Message Terminator The <NL> (newline) indicator. Terminators are not part of the SCPI syntax
2.5.3 Headers
Headers are instructions recognized by the AC source. Headers (which are sometimes known as
"keywords") may be either in the long form or the short form.
Long Form The header is completely spelled out, such as VOLTAGE, STATUS, and
DELAY.
Short Form The header has only the first three or four letters, such as VOLT, STAT,
and DEL.
The SCPI interface is not sensitive to case. It will recognize any case mixture, such as TRIGGER,
Trigger, TRIGger. Short form headers result in faster program execution.
Header Convention
In the command descriptions in chapter 3 of this manual, headers are emphasized with boldface
type. The proper short form is shown in upper-case letters, such as DELay.
Header Separator
If a command has more than one header, you must separate them with a colon (VOLT:PROT
OUTPut:RELay:POLarity).
Optional Headers
The use of some headers is optional. Optional headers are shown in brackets, such as
OUTPut[:STATe] ON. As previously explained under "The Effect of Optional Headers", if you

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combine two or more message units into a compound message, you may need to enter the
optional header.
2.5.4 Query Indicator
Following a header with a question mark turns it into a query (VOLTage?,
VOLTage:PROTection?). If a query contains a parameter, place the query indicator at the end of
the last header (VOLTage:PROTection? MAX).
2.5.5 Message Unit Separator
When two or more message units are combined into a compound message, separate the units
with a semicolon (STATus:OPERation?;QUEStionable?).
2.5.6 Root Specifier
When it precedes the first header of a message unit, the colon becomes the root specifier. It tells
the command parser that this is the root or the top node of the command tree. Note the difference
between root specifiers and header separators in the following examples:
OUTPut:PROTection:DELay .1 All colons are header separators
:OUTPut:PROTection:DELay .1 Only the first colon is a root specifier
OUTPut:PROTection:DELay .1;:VOLTage 12.5 Only the third colon is a root specifier
Note: You do not have to precede root-level commands with a colon; there is an implied colon in
front of every root-level command.
2.5.7 Message Terminator
A terminator informs SCPI that it has reached the end of a message. Three permitted messages
terminators are:
newline (<NL>), which is ASCII decimal 10 or hex 0A.
end or identify (<END>)
both of the above (<NL><END>).
In the examples of this manual, there is an assumed message terminator at the end of each
message. If the terminator needs to be shown, it is indicated as <NL> regardless of the actual
terminator character.