I-Tech IT-M3100 Operating instructions

Programmable DC Power
Supply
IT-M3100 Programming Guide
Model: IT-M3100
Version: V1.0 / 03, 2019

Notices
© Itech Electronic, Co., Ltd. 2019
No part of this manual may be
reproduced in any form or by any means
(including electronic storage and
retrieval or translation into a foreign
language) without prior permission and
written consent from Itech Electronic,
Co., Ltd. as governed by international
copyright laws.
Manual Part Number
IT-M3100-402225
Revision
1st Edition: Mar. 4, 2019
Itech Electronic, Co., Ltd.
Trademarks
Pentium is U.S. registered trademarks
of Intel Corporation.
Microsoft, Visual Studio, Windows and
MS Windows are registered trademarks
of Microsoft Corporation in the United
States and/or other countries and
regions.
Warranty
The materials contained in this
document are provided “as is” , and
is subject to change, without prior
notice, in future editions. Further, to
the maximum extent permitted by
applicable laws, ITECH disclaims
all warrants, either express or
implied, with regard to this manual
and any information contained
herein, including but not limited to
the implied warranties of
merchantability and fitness for a
particular purpose. ITECH shall
not be held liable for errors or for
incidental or indirect damages in
connection with the furnishing, use
or application of this document or of
any information contained herein.
Should ITECH and the user enter
into a separate written agreement
with warranty terms covering the
materials in this document that
conflict with these terms, the
warranty terms in the separate
agreement shall prevail.
Technology Licenses
The hardware and/or software
described herein are furnished under a
license and may be used or copied only
in accordance with the terms of such
license.
Restricted Rights Legend
Restricted permissions of the U.S.
government. Permissions for software
and technical data which are authorized
to the U.S. Government only include
those for custom provision to end users.
ITECH provides this customary
commercial license in software and
technical data pursuant to FAR 12.211
( Technical Data) and 12.212
( Computer Software) and, for the
Department of Defense, DFARS
252.227-7015 ( Technical Data –
Commercial Items) and DFARS
227.7202-3 ( Rights in Commercial
Computer Software or Computer
Software Documentation).
Safety Notices
A CAUTION sign denotes a
hazard. It calls attention to an
operating procedure or practice
that, if not correctly performed
or adhered to, could result in
damage to the product or loss of
important data. Do not proceed
beyond a CAUTION sign until
the indicated conditions are fully
understood and met.
A WARNING sign denotes a
hazard. It calls attention to an
operating procedure or practice
that, if not correctly performed
or adhered to, could result in
personal injury or death. Do not
proceed beyond a WARNING
sign until the indicated
conditions are fully understood
and met.
NOTE
A NOTE sign denotes important
hint. It calls attention to tips or
supplementary information that
is essential for users to refer to

IT-M3100 Programming Guide
Copyright © Itech Electronic Co., Ltd. i
Quality Certification and Assurance
We certify that IT-M3100 power supply meets all the published specifications at
time of shipment from the factory.
Warranty ITECH warrants that the product will be free from defects in material and
workmanship under normal use for a period of one (1) year from the date of
delivery (except those described in the Limitation of Warranty below).
For warranty service or repair, the product must be returned to a service center
designated by ITECH.
⚫The product returned to ITECH for warranty service must be shipped
PREPAID. And ITECH will pay for return of the product to customer.
⚫If the product is returned to ITECH for warranty service from overseas, all
the freights, duties and other taxes shall be on the account of customer.
Limitation of Warranty
This Warranty will be rendered invalid in case of the following:
⚫Damage caused by circuit installed by customer or using customer own
products or accessories;
⚫Modified or repaired by customer without authorization;
⚫Damage caused by circuit installed by customer or not operating our
products under designated environment;
⚫The product model or serial number is altered, deleted, removed or made
illegible by customer;
⚫Damaged as a result of accidents, including but not limited to lightning,
moisture, fire, improper use or negligence.
Safety Symbols
Direct current
ON (power on)
Alternating current
OFF (power off)
Both direct and alternating
current
Power-on state
Protective conductor terminal
Power-off state

IT-M3100 Programming Guide
Copyright © Itech Electronic Co., Ltd. ii
Earth (ground) terminal
Reference
terminal
Caution, risk of electric shock
Positive terminal
Warning, risk of danger (refer
to this manual for specific
Warning or Caution
information)
Negative terminal
Frame or chassis terminal
-
-
Safety Precautions
The following safety precautions must be observed during all phases of
operation of this instrument. Failure to comply with these precautions or specific
warnings elsewhere in this manual will constitute a default under safety
standards of design, manufacture and intended use of the instrument. ITECH
assumes no liability for the customer’s failure to comply with these precautions.
⚫Do not use the instrument if it is damaged. Before operation, check the
casing to see whether it cracks. Do not operate the instrument in the
presence of inflammable gasses, vapors or dusts.
⚫The power supply is provided with a three-core power line during delivery
and should be connected to a three-core junction box. Before operation, be
sure that the instrument is well grounded.
⚫Make sure to use the power cord supplied by ITECH.
⚫Check all marks on the instrument before connecting the instrument to
power supply.
⚫Use electric wires of appropriate load. All loading wires should be capable
of bearing maximum short-circuit current of power supply without
overheating. If there are multiple electronic loads, each pair of the power
cord must be capable of bearing the full-loaded rated short-circuit output
current.
⚫Ensure the voltage fluctuation of mains supply is less than 10% of the
working voltage range in order to reduce risks of fire and electric shock.
⚫Do not install alternative parts on the instrument or perform any
unauthorized modification.
⚫Do not use the instrument if the detachable cover is removed or loosen.
⚫To prevent the possibility of accidental injuries, be sure to use the power
adapter supplied by the manufacturer only.
⚫We do not accept responsibility for any direct or indirect financial damage
or loss of profit that might occur when using the instrument.
⚫This instrument is used for industrial purposes, do not apply this product to
IT power supply system.

IT-M3100 Programming Guide
Copyright © Itech Electronic Co., Ltd. iii
⚫Never use the instrument with a life-support system or any other equipment
subject to safety requirements.
⚫Failure to use the instrument as directed by the manufacturer may render
its protective features void.
⚫Always clean the casing with a dry cloth. Do not clean the internals.
⚫Make sure the vent hole is always unblocked.
Environmental Conditions
The instrument is designed for indoor use and an area with low condensation.
The table below shows the general environmental requirements for the
instrument.
Environmental Conditions
Requirements
Operating temperature
0°C to 40°C
Operating humidity
20%-80% (non-condensation)
Storage temperature
-20°C to 70 °C
Altitude
Operating up to 2,000 meters
Pollution degree
Pollution degree 2
Installation category
II
Note
To make accurate measurements, allow the instrument to warm up for 30 min before
operation.
Regulatory Markings
The CE mark indicates that the product
complies with all the relevant European
legal directives. The specific year (if any)
affixed refers to the year when the design
was approved.
The instrument complies with the WEEE
Directive (2002/96/EC) marking
requirement. This affixed product label
indicates that you must not discard the
electrical/electronic product in domestic
household waste.

IT-M3100 Programming Guide
Copyright © Itech Electronic Co., Ltd. iv
This symbol indicates the time period
during which no hazardous or toxic
substances are expected to leak or
deteriorate during normal use. The
expected service life of the product is 10
years. The product can be used safely
during the 10-year Environment Friendly
Use Period (EFUP). Upon expiration of
the EFUP, the product must be
immediately recycled.
Waste Electrical and Electronic Equipment (WEEE)
Directive
2002/96/EC Waste Electrical and Electronic Equipment
(WEEE) Directive
This product complies with the WEEE Directive (2002/96/EC)
marking requirement. This affix product label indicates that you
must not discard the electrical/electronic product in domestic
household waste.
Product Category
With reference to the equipment classifications described in the
Annex I of the WEEE Directive, this instrument is classified as a
“Monitoring and Control Instrument”.
To return this unwanted instrument, contact your nearest
ITECH office.

IT-M3100 Programming Guide
Copyright © Itech Electronic Co., Ltd. v
Compliance Information
Complies with the essential requirements of the following applicable European
Directives, and carries the CE marking accordingly:
⚫Electromagnetic Compatibility (EMC) Directive 2014/30/EU
⚫Low-Voltage Directive (Safety) 2014/35/EU
Conforms with the following product standards:
EMC Standard
IEC 61326-1:2012/ EN 61326-1:2013 ¹²³
Reference Standards
CISPR 11:2009+A1:2010/ EN 55011:2009+A1:2010 (Group 1, Class A)
IEC 61000-4-2:2008/ EN 61000-4-2:2009
IEC 61000-4-3:2006+A1:2007+A2:2010/ EN 61000-4-3:2006+A1:2008+A2:2010
IEC 61000-4-4:2004+A1:2010/ EN 61000-4-4:2004+A1:2010
IEC 61000-4-5:2005/ EN 61000-4-5:2006
IEC 61000-4-6:2008/ EN 61000-4-6:2009
IEC 61000-4-11:2004/ EN 61000-4-11:2004
1. The product is intended for use in non-residential/non-domestic environments. Use of the
product in residential/domestic environments may cause electromagnetic interference.
2. Connection of the instrument to a test object may produce radiations beyond the specified
limit.
3. Use high-performance shielded interface cable to ensure conformity with the EMC standards
listed above.
Safety Standard
IEC 61010-1:2010/ EN 61010-1:2010

IT-M3100 Programming Guide
Copyright © Itech Electronic Co., Ltd. vi
Content
Quality Certification and Assurance............................................................................................................................i
Warranty .....................................................................................................................................................................i
Limitation of Warranty ................................................................................................................................................i
Safety Symbols ............................................................................................................................................................i
Safety Precautions......................................................................................................................................................ii
Environmental Conditions.........................................................................................................................................iii
Regulatory Markings .................................................................................................................................................iii
Waste Electrical and Electronic Equipment (WEEE) Directive...................................................................................iv
Compliance Information ............................................................................................................................................v
Chapter1 SCPI Introduction ........................................................................................................................... 1
1.1 Overview ..............................................................................................................................................................1
1.2 Command Type of SCPI ........................................................................................................................................1
1.3 Message Type of SCPI...........................................................................................................................................3
1.4 Response Data Type .............................................................................................................................................5
1.5 Command Format ................................................................................................................................................6
1.6 Data Type .............................................................................................................................................................8
1.7 Remote Interface Connections.............................................................................................................................9
Chapter2 Status register ................................................................................................................................ 1
Chapter3 Channel Selection Commands ........................................................................................................ 4
CHANnel <NR1> .........................................................................................................................................................4
INSTrument[:SELect] <NR1>.......................................................................................................................................4
CHANnel:STATe? <NR1> .............................................................................................................................................5
Chapter4 Output Commands ......................................................................................................................... 6
OUTPut[:STATe] <bool> ..............................................................................................................................................6
[OUTPut:]PROTection:CLEar .......................................................................................................................................6
OUTPut:DELay[:ON] <NRf+>.......................................................................................................................................7
OUTPut:DELay:OFF <NRf+> ........................................................................................................................................7
OUTPut:DELay[:RISE] <NRf+> .....................................................................................................................................8
OUTPut:DELay:FALL <NRf+> .......................................................................................................................................8
[OUTPut:]TIMer[:STATe] .............................................................................................................................................9
[OUTPut:]TIMer:DELay...............................................................................................................................................9
OUTPut:PONSetup[:STATe] <RST|LAST|LOFF>.........................................................................................................10
[OUTPut:]PROTection:WDOG[:STATe] <Bool> ..........................................................................................................10
[OUTPut:]PROTection:WDOG:DELay [MINimum|MAXimum]..................................................................................11
Chapter5 Measurement Commands ............................................................................................................ 12
MEASure[:SCALar]:CURRent[:DC]?...........................................................................................................................12
FETCh[:SCALar]:CURRent[:DC]?................................................................................................................................12
MEASure[:SCALar]:POWer[:DC]? .............................................................................................................................12
FETCh[:SCALar]:POWer[:DC]?...................................................................................................................................13
MEASure[:SCALar]:VOLTage[:DC]? ...........................................................................................................................13
FETCh[:SCALar]:VOLTage[:DC]? ................................................................................................................................14
MEASure[:SCALar]:CAPacity? ...................................................................................................................................14

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FETCh[:SCALar]:CAPacity? ........................................................................................................................................15
MEASure?.................................................................................................................................................................15
FETCh?......................................................................................................................................................................15
FETCh:TIME? ............................................................................................................................................................16
Chapter6 Sense Commands ......................................................................................................................... 17
SENSe[:REMote][:STATe] <bool> ..............................................................................................................................17
SENSe:FILTer:LEVel <SLOW|MEDium|FAST>............................................................................................................17
SENSe:AHOur:CLEar .................................................................................................................................................18
Chapter7 Source Commands........................................................................................................................ 19
[SOURce:]CURRent[:LEVel][:IMMediate][:AMPLitude] <NRf+> ...............................................................................19
[SOURce:]CURRent[:LEVel]:TRIGgered[:AMPLitude] <NRf+> ...................................................................................19
[SOURce:]CURRent[:OVER]:PROTection[:LEVel] <NRf+> ..........................................................................................20
[SOURce:]CURRent[:OVER]:PROTection:DELay <NRf+> ...........................................................................................20
[SOURce:]CURRent[:OVER]:PROTection:STATe <bool> .............................................................................................21
[SOURce:]CURRent:UNDer:PROTection[:LEVel] <NRf+>...........................................................................................21
[SOURce:]CURRent:UNDer:PROTection:DELay <NRf+> ............................................................................................22
[SOURce:]CURRent:UNDer:PROTection:STATe <bool> .............................................................................................22
[SOURce:]CURRent:UNDer:PROTection:WARM <NRf+> ..........................................................................................23
[SOURce:]CURRent:SLEW[:BOTH] <NRf+>,<NRf+>...................................................................................................23
[SOURce:]CURRent:SLEW:NEGative <NRf+> ............................................................................................................24
[SOURce:]CURRent:SLEW:POSitive <NRf+>..............................................................................................................24
[SOURce:]VOLTage[:LEVel][:IMMediate][:AMPLitude] <NRf+> ................................................................................25
[SOURce:]VOLTage[:LEVel]:TRIGgered[:AMPLitude] <NRf+>....................................................................................25
[SOURce:]VOLTage:SLEW[:BOTH] <NRf+>,<NRf+> ...................................................................................................26
[SOURce:]VOLTage:SLEW:NEGative <NRf+> .............................................................................................................26
[SOURce:]VOLTage:SLEW:POSitive <NRf+> ..............................................................................................................27
[SOURce:]VOLTage[:OVER]:PROTection[:LEVel] <NRf+> ...........................................................................................27
[SOURce:]VOLTage[:OVER]:PROTection:DELay <NRf+> ............................................................................................28
[SOURce:]VOLTage[:OVER]:PROTection:STATe <bool>..............................................................................................28
[SOURce:]VOLTage:UNDer:PROTection[:LEVel] <NRf+> ...........................................................................................29
[SOURce:]VOLTage:UNDer:PROTection:DELay <NRf+>.............................................................................................30
[SOURce:]VOLTage:UNDer:PROTection:STATe <bool> ..............................................................................................30
[SOURce:]VOLTage:UNDer:PROTection:WARM <NRf+> ...........................................................................................31
[SOURce:]VOLTage[:LEVel]:LIMit[:HIGH] <NRf+> .....................................................................................................31
[SOURce:]VOLTage[:LEVel]:LIMit:LOW <NRf+>.........................................................................................................32
[SOURce:]POWer[:LEVel][:IMMediate][:AMPLitude] <NRf+> ..................................................................................32
[SOURce:]POWer:PROTection[:LEVel] <NRf+> .........................................................................................................33
[SOURce:]POWer:PROTection:DELay <NRf+>...........................................................................................................33
[SOURce:]POWer:PROTection:STATe <Bool> ............................................................................................................34
[SOURce:]FUNCtion:MODE <FIXed|LIST|BATTery>..................................................................................................34
[SOURce:]FUNCtion:PRIority <VOLTage|CURRent> .................................................................................................35
[SOURce:]APPLy <NRf+>,<NRf+>..............................................................................................................................35
[SOURce:]EXTernal[:STATe] <bool>...........................................................................................................................36
[SOURce:]BLEeder[:STATe] .......................................................................................................................................36

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Chapter8 System Commands ....................................................................................................................... 37
SYSTem:BEEPer:IMMediate......................................................................................................................................37
SYSTem:BEEPer[:STATe] <bool> ................................................................................................................................37
SYSTem:VERSion? .....................................................................................................................................................38
SYSTem:ERRor?.........................................................................................................................................................38
SYSTem:CLEar ...........................................................................................................................................................39
SYSTem:REMote .......................................................................................................................................................39
SYSTem:LOCal ...........................................................................................................................................................40
SYSTem:RWLock .......................................................................................................................................................40
SYSTem:KEY <NR1>...................................................................................................................................................41
SYSTem:REBoot ........................................................................................................................................................41
SYSTem:COMMunicate:GPIB[:SELF]:ADDRess <NR1> ..............................................................................................42
SYSTem:COMMunicate:LAN:CURRent:ADDRess <SPD> ...........................................................................................42
SYSTem:COMMunicate:LAN:CURRent:DGATeway <SPD>.........................................................................................43
SYSTem:COMMunicate:LAN:CURRent:SMASk <SPD> ..............................................................................................43
SYSTem:COMMunicate:LAN:DHCP <Bool>...............................................................................................................44
SYSTem:COMMunicate:LAN:SOCKetport <NR1>......................................................................................................44
SYSTem:COMMunicate:LAN:MACaddress? ..............................................................................................................45
SYSTem:COMMunicate:LAN:RESTart ........................................................................................................................45
SYSTem:COMMunicate:SERial:BAUDrate .................................................................................................................46
SYSTem:COMMunicate:LAN:DNS1 <SPD> ................................................................................................................46
SYSTem:COMMunicate:LAN:DNS2 <SPD> ................................................................................................................47
SYSTem:COMMunicate:LAN:RESTore .......................................................................................................................47
SYSTem:COMMunicate:LAN:RESet ...........................................................................................................................48
SYSTem:COMMunicate:LAN:STATe? .........................................................................................................................48
SYSTem:COMMunicate:LAN:HOSTname? ................................................................................................................49
SYSTem:COMMunicate:LAN:DESCription? ...............................................................................................................49
SYSTem:COMMunicate:LAN:DOMain? .....................................................................................................................50
SYSTem:READy?........................................................................................................................................................50
Chapter9 List Commands ............................................................................................................................. 52
LIST:STEP:COUNt <NR1> ..........................................................................................................................................52
LIST:STEP:VOLTage <NR1>,<NRf+> ..........................................................................................................................52
LIST:STEP:CURRent <NR1>,<NRf+> ..........................................................................................................................53
LIST:STEP:SLEW <NR1>,<NRf+>................................................................................................................................53
LIST:STEP:WIDTh <NR1>,<NRf+>..............................................................................................................................54
LIST:REPeat <NR1> ...................................................................................................................................................54
LIST:FUNCtion <VOLTage|CURRent> .......................................................................................................................55
LIST:SAVE <NR1> ......................................................................................................................................................55
LIST:RECall <NR1> ....................................................................................................................................................56
LIST[:STATe] <bool> .................................................................................................................................................56
LIST:TERMinate <NORMal|LAST> ............................................................................................................................57
LIST:PAUSe[:STATe] <BOOLEAN> .............................................................................................................................57
LIST:RUN:STEP? ........................................................................................................................................................58
LIST:RUN:REPeat? ....................................................................................................................................................58
Chapter10 Trace Commands ...................................................................................................................... 59

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TRACe:CLEar.............................................................................................................................................................59
TRACe:POINts <NR1> ...............................................................................................................................................59
TRACe:FEED:CONTrol <NEVer|NEXT|ALWays> .......................................................................................................60
TRACe:FEED[:SELected] <VOLTage|CURRent|BOTH> .............................................................................................60
TRACe:DELay <NRf+> ...............................................................................................................................................61
TRACe:TIMer <NRf+> ...............................................................................................................................................61
TRACe:POINts:ACTual?.............................................................................................................................................62
TRACe:DATA? ...........................................................................................................................................................62
TRACe:FILTer[:STATe]...............................................................................................................................................63
Chapter11 Battery Commands................................................................................................................... 64
BATTery:CHARge:VOLTage <NRf+> ..........................................................................................................................64
BATTery:CHARge:CURRent <NRf+>..........................................................................................................................64
BATTery:STOP:VOLTage <NRf+> ..............................................................................................................................65
BATTery:STOP:CURRent <NRf+> ..............................................................................................................................65
BATTery:STOP:CAPacity <NRf+> ..............................................................................................................................66
BATTery:STOP:TIME <NRf+> ....................................................................................................................................66
BATTery[:STATe] ......................................................................................................................................................67
Chapter12 Parallel Commands................................................................................................................... 68
PARallel:ROLE <SINGle|SLAVe|MASTer>.................................................................................................................68
PARallel:GROup <NR1> ............................................................................................................................................68
PARallel[:UNIT]:NUMBer <NR1> ..............................................................................................................................69
Chapter13 Link Commands........................................................................................................................ 70
LINK:MODE <OUTPut|TRACk|DUPLicate>...............................................................................................................70
LINK[:STATe] <bool>.................................................................................................................................................70
LINK:REFerence <NRf+> ...........................................................................................................................................71
Chapter14 Status Commands..................................................................................................................... 72
STATus:OPERation[:EVENt]? ....................................................................................................................................72
STATus:OPERation:CONDition?................................................................................................................................72
STATus:OPERation:ENABle <NR1> ...........................................................................................................................73
STATus:OPERation:NTRansition <NR1> ...................................................................................................................73
STATus:OPERation:PTRansition <NR1>....................................................................................................................74
STATus:QUEStionable[:EVENt]? ...............................................................................................................................74
STATus:QUEStionable:CONDition? ..........................................................................................................................74
STATus:QUEStionable:ENABle <NR1> ......................................................................................................................75
STATus:QUEStionable:NTRansition <NR1> ..............................................................................................................75
STATus:QUEStionable:PTRansition <NR1>...............................................................................................................76
STATus:PRESet .........................................................................................................................................................76
Chapter15 Trigger Commands ................................................................................................................... 78
TRIGger[:IMMediate] ...............................................................................................................................................78
TRIGger:SOURce <KEYPad|BUS|EXT>......................................................................................................................78
TRIGger:PIN:DIRection <IN|OUT> ............................................................................................................................79
Chapter16 Common Commands ................................................................................................................ 80

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*CLS..........................................................................................................................................................................80
*ESE..........................................................................................................................................................................80
*ESR?........................................................................................................................................................................81
*IDN?........................................................................................................................................................................81
*OPC.........................................................................................................................................................................82
*PSC .........................................................................................................................................................................83
*RCL .........................................................................................................................................................................83
*RST..........................................................................................................................................................................84
*SAV .........................................................................................................................................................................84
*SRE .........................................................................................................................................................................85
*STB?........................................................................................................................................................................85
*TRG.........................................................................................................................................................................86
*TST?........................................................................................................................................................................86
*WAI.........................................................................................................................................................................87
Chapter17 Programming Examples ............................................................................................................ 88
Example1: Identifying the Power Supply in Use...........................................................................................88
Example2: Setting the Common Output Arguments....................................................................................88
Example3: List Function...................................................................................................................................89
Example4: Battery Charging Test Function...................................................................................................90
Chapter18 Error Messages......................................................................................................................... 91
Error List...................................................................................................................................................................91

SCPI Introduction
Copyright © Itech Electronic Co., Ltd. 1
Chapter1 SCPI Introduction
1.1 Overview
SCPI is short for Standard Commands for Programmable Instruments which
defines a communication method of bus controller and instrument. It is based
on ASCII and supply for testing and measuring instruments. SCPI command is
based on hierarchical architecture which also known as tree system. In this
system, Relevant Command is returned to a common node or root, so that a
subsystem is formed.A part of OUTPut subsystem is listed below:
OUTPut:
•SYNC {OFF|0|ON|1}
•SYNC:
–MODE {NORMal|CARRier}
–POLarity {NORMal|INVerted}
OUTPut is the root class keyword, SYNC is the second keyword, MODE and
POLarity are the third keyword. Colon(:) is used for separating the command
keyword and the next level keyword.
1.2 Command Type of SCPI
SCPI has two types of commands, common and subsystem.
⚫Common commands generally are not related to specific operation but to
controlling overall instrument functions, such as reset, status, and
synchronization. All commoncommands consist of a three-letter mnemonic
preceded by an asterisk: *RST *IDN? *SRE 8.
⚫Subsystem commands perform specific instrument functions. They are
organized into an inverted tree structure with the "root" at the top. The
following figure shows a portion of a subsystem command tree, from which
you access the commands located along the various paths.
Multiple Commands in a Message
Multiple SCPI commands can be combined and sent as a single
message with one message terminator. There are two important
considerations when sending several commands within a single

SCPI Introduction
Copyright © Itech Electronic Co., Ltd. 2
message:
⚫Use a semicolon to separate commands within a message.
⚫Head paths influence how the instrument interprets commands.
We consider the head path as a string which will be inserted in front of
every command of a message. As for the first command of a message,
the head path is a null string; for each subsequent command, the head
path is a string which is defined to form the current command until and
including the head of the last colon separator. A message with two
combined commands:
CURR:LEV 3;PROT:STAT OFF
The example indicates the effect of semicolon and explains the concept
of head path. Since the head path is defined to be "CURR" after "curr: lev
3", the head of the second command, "curr", is deleted and the
instrument explains the second command as:
CURR:PROT:STAT OFF
If "curr" is explicitly included in the second command, it is semantically
wrong. Since combining it with the head path will become
"CURR:CURR:PROT:STAT OFF", resulting in wrong command.
Movement in the Subsystem
In order to combine commands from different subsystems, you need to
be able to reset the header path to a null string within a message. You do
this by beginning the command with a colon (:), which discards any
previous header path. For example, you could clear the output protection
and check the status of the Operation Condition register in one message
by using a root specifier as follows:
PROTection:CLEAr;:STATus:OPERation:CONDition?
The following message shows how to combine commands from different
subsystems as well as within the same subsystem:
POWer:LEVel 200;PROTection 28; :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.
Including Common Commands
You can combine common commands with subsystem 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 header path; you may insert them anywhere
in the message.
VOLTage:TRIGgered 17.5;:INITialize;*TRG
OUTPut OFF;*RCL 2;OUTPut ON

SCPI Introduction
Copyright © Itech Electronic Co., Ltd. 3
Case Sensitivity
Common commands and SCPI commands are not case sensitive. You
can use upper or lower, for example:
*RST = *rst
:DATA? = :data?
:SYSTem:PRESet = :system:preset
Long-Form and Short-Form Versions
A SCPI command word can be sent in its long-form or short-form version.
However, the short-form version is indicated by upper case characters.
Examples:
:SYSTem:PRESet long-form
:SYST:PRES short form
:SYSTem:PRES long-form and short-form combination
Note that each command word must be in long-form or short-form, and
not something in between.
For example, :SYSTe:PRESe is illegal and will generate an error. The
command will not be executed.
Query Observe the following precautions with queries:
⚫Set up the proper number of variables for the returned data. For example, if
you are reading back a measurement array, you must dimension the array
according to the number of measurements that you have placed in the
measurement buffer.
⚫Read back all the results of a query before sending another command to
the instrument. Otherwise a Query Interrupted error will occur and the
unreturned data will be lost.
1.3 Message Type of SCPI
There are two types of SCPI messages, program and response.
⚫Program message: A program message consists of one or more properly
formatted SCPI commands sent from the controller to the instrument. The
message, which may be sent at any time, requests the instrument to
perform some action.
⚫Response message: A response message consists of data in a specific
SCPI format sent from the instrument to the controller. The instrument
sends the message only when commanded by a program message called
a "query."
The next figure illustrates SCPI message structure:

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Copyright © Itech Electronic Co., Ltd. 4
The message unit
The simplest SCPI command is a single message unit consisting of a command
header (or keyword) followed by a message terminator. The message unit may
include a parameter after the header. The parameter can be numeric or a
string.
ABORt<NL>
VOLTage 20<NL>
Headers Headers, also referred to as keywords, are instructions recognized by the
instrument. Headers may be either in the long form or the short form. In the long
form, the header is completely spelled out, such as VOLTAGE, STATUS and
DELAY. In the short form, the header has only the first three or four letters, such
as VOLT, STAT and DEL.
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).
Message unit separator
When two or more message units are combined into a compound message,
separate the units with a semicolon (STATus:OPERation?;QUEStionable?).
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.
Message terminator
A terminator informs SCPI that it has reached the end of a message. Three
permitted message terminators are:
⚫newline (<NL>), decimal 10 or hexadecimal 0X0Ain ASCII.
⚫end or identify (<END>)
⚫both of the above (<NL><END>).
In the examples of this guide, there is an assumed message terminator at the

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Copyright © Itech Electronic Co., Ltd. 5
end of each message.
Command execution rules
⚫Commands execute in the order that they are presented in the program
message.
⚫An invalid command generates an error and, of course, is not executed.
⚫Valid commands that precede an invalid command in a multiple command
program message are executed.
⚫Valid commands that follow an invalid command in a multiple command
program message are ignored.
1.4 Response Data Type
Character strings returned by query statements may take either of the following
forms, depending on the length of the returned string:
⚫<CRD>: character response data. Permits the return of character strings.
⚫<AARD>: arbitrary ASCII response data. Permits the return of undelimited
7-bit ASCII. This data type has an implied message terminator.
⚫<SRD>: string response data. Returns string parameters enclosed in
double quotes.
⚫<Block>: arbitrary block data.
Response messages
A response message is the message sent by the instrument to the computer in
response to a query command.
Sending a response message
After sending a query command, the response message is placed in the Output
Queue. When the instrument is then addressed to talk, the response message
is sent from the Output Queue to the computer
Multiple response messages
If you send more than one query command in the same program message, the
multiple response messages for all the queries is sent to the computer when
the instrument is addressed to talk. The responses are sent in the order that the
query commands were sent and are separated by semicolons (;). Items within
the same query are separated by commas (,). The following example shows the
response message for a program message that contains four single item query
commands:
0; 1; 1; 0
Response message terminator (RMT)
Each response is terminated with an LF (line feed) and EOI (end or identify).
The following example shows how a multiple response message is terminated:
0; 1; 1; 0; <RMT>
Message exchange protocol
Two rules summarize the message exchange protocol:

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⚫Rule 1: You must always tell the instrument what to send to the computer.
The following two steps must always be performed to send information
from the instrument other computer:
1. Send the appropriate query command(s) in a program message.
2. Address the instrument to talk.
⚫Rule 2: The complete response message must be received by the
computer before another program message can be sent to the instrument.
1.5 Command Format
Formats for command display are as follows:
[SOURce[1|2]:]VOLTage:UNIT {VPP|VRMS|DBM}
[SOURce[1|2]:]FREQuency:CENTer
{<frequency>|MINimum|MAXimum|DEFault}
Based on the command syntax, most commands (and certain Parameter) are
expressed in both upper and lower cases. Upper case refers to abbreviation of
commands. Shorter program line may send commands in abbreviated format.
Long-format commands may be sent to ensure better program readability.
For example, both formats of VOLT and VOLTAGE are acceptable in the above
syntax statements. Upper or lower case may be used. Therefore, formats of
VOLTAGE, volt and Volt are all acceptable. Other formats (such as VOL and
VOLTAG) are invalid and will cause errors.
⚫Parameter options with given command strings are included in the brace
({ }). The brace is not sent along with command strings.
⚫Vertical stripes (|) separate several parameter options with given command
strings. For example, {VPP|VRMS|DBM} indicates that you may assign
"APP", "VRMS" or "DBM" in the above commands. Vertical stripes are not
sent along with command strings.
⚫Angle brackets (< >) in the second example indicates that a value must be
assigned to the parameter in the brace. For example, the parameter in the
angle bracket is <frequency> in the above syntax statements. Angle
brackets are not sent along with command strings. You must assign a value
(such as "FREQ:CENT 1000") to the parameter, unless you select other
options displayed in the syntax (such as "FREQ:CENT MIN").
⚫Some syntax elements (such as nodes and Parameter) are included in
square brackets ([ ]). It indicates that these elements can be selected and
omitted. Angle brackets are not sent along with command strings. If no
value is assigned to the optional Parameter, the instrument will select a
default value. In the above examples, "SOURce[1|2]" indicates that you
may refer to source channel 1 by "SOURce" or "SOURce1" or "SOUR1" or
"SOUR". In addition, since the whole SOURce node is optional (in the
square bracket), you can refer to the channel 1 by omitting the whole
SOURce node. It is because the channel 1 is the default channel for
SOURce language node. On the other hand, if you want to refer to channel
2, "SOURce2" or "SOUR2" must be used in the program line.
Colon (:) It is used to separate key words of a command with the key words in next level.
As shown below:
APPL:SIN 455E3,1.15,0.0

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In this example, APPLy command assigns a sine wave with frequency of 455
KHz, amplitude of 1.15 V and DC offset of 0.0 V.
Semicolon (;) It is used to separate several commands in the same subsystem and can also
minimize typing. For example, to send the following command string:
TRIG:SOUR EXT; COUNT 10
has the same effect as sending the following two commands:
TRIG:SOUR EXT
TRIG:COUNT 10
Question mark (?)
You can insert question marks into a command to query current values of most
Parameter. For example, the following commands will trigger to set the count as
10:
TRIG:COUN 10
Then, you may query count value by sending the following command:
TRIG:COUN?
You may also query the allowable minimum or maximum count as follows:
TRIG:COUN?MIN
TRIG:COUN?MAX
Comma (,) If a command requires several Parameter, then a comma must be used to
separate adjacent Parameter.
Space You must use blank characters, [TAB] or [Space] to separate Parameter with
key words of commands.
Common commands (*)
The IEEE-488.2 standard defines a set of common commands that perform
functions such as reset, self-test, and status operations. Common commands
always start with a asterisk (*) and occupy 3 character sizes, including one or
more Parameter. Key words of a command and the first parameter are
separated by a space. Semicolon (;) can separate several commands as
follows:
*RST; *CLS; *ESE 32; *OPC?
Command terminator
Command strings sent to the instrument must end with a <Newline> (<NL>)
character. IEEE-488 EOI (End or Identify) information can be used as <NL>
character to replace termination command string of <NL> character. It is
acceptable to place one <NL> after a <Enter>. Termination of command string
always resets current SCPI command path to root level.

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NOTE
As for every SCPI message with one query sent to the instrument, the
instrument will use a <NL> or newline sign (EOI) to terminate response of
return. For example, if "DISP:TEXT?" is sent, <NL> will be placed after
the returned data string to terminate response. If an SCPI message
includes several queries separated by semicolon (such as
"DISP?;DISP:TEXT?"), <NL> will terminate response returned after
response to the last query. In all cases, the program must read <NL> in
response before another command is sent to the instrument, otherwise
errors will be caused.
1.6 Data Type
SCPI language defines several data types used for program message and
response messages.
⚫Numerical parameter
Commands requiring numerical parameter support the notations of all
common decimal notations, including optional signs, decimal points,
scientific notation, etc. Special values of numerical parameter are also
acceptable, such as MIN, MAX and DEF. In addition, suffixes for
engineering units can also be sent together with numerical parameter
(including M, k, m or u). If the command accepts only some specific values,
the instrument will automatically round the input parameter to acceptable
values. The following commands require numerical parameter of frequency
value:
[SOURce[1|2]:]FREQuency:CENTer
{<Frequency>|MINimum|MAXimum}
–<NR1>: represents an integer value, such as 273;
–<NR2>: represents a real number in floating-point format, such as .273;
–<NR3>: represents a real number in scientific notation, such as
2.73E+2;
–<Nrf>: The extensible form includes <NR1>, <NR2> and <NR3>;
–<Nrf+>: The extensible decimal form includes <Nrf>, MIN, MAX and
DEF. MIN and MAX are the minimum and maximum finite number. Within
the range of the parameter definition, DEF is the default of the parameter.
⚫Discrete parameter
Discrete parameter are used for settings with limited number of
programming values (such as IMMediate, EXTernal or BUS). They can use
short and long format like key words of commands. They may be
expressed in both upper and lower case. The query response always
returns uppercase Parameter in short format. The following commands
require discrete parameter in voltage unit:
[SOURce[1|2]:]VOLTage:UNIT {VPP|VRMS|DBM}
⚫Boolean parameter
Boolean parameter refer to true or false binary conditions. In case of false
conditions, the instrument will accept "OFF" or "0". In case of true
conditions, the instrument will accept "ON" or "1". In query of Boolean
settings, the instrument will always return "0" or "1". Boolean parameter are
required by the following commands:
DISPlay {OFF|0|ON|1}
⚫ASCII string parameter
String parameter may actually include all ASCII character sets. Character