Tektronix Keithley 2281 Series User manual

Reference Manual
077114601 / March 2019
*P077114601*
077114601
Model 2281S-20-6 Precision DC
Power Supply and Battery Simulator
tek.com/keithley

DC Power Supply and Battery Simulator
Reference Manual
Model 2281S-20-6

© 2019, Keithley Instruments, LLC
Cleveland, Ohio, U.S.A.
All rights reserved.
Any unauthorized reproduction, photocopy, or use of the information herein, in whole or in part,
without the prior written approval of Keithley Instruments, LLC, is strictly prohibited.
These are the original instructions in English.
All Keithley Instruments product names are trademarks or registered trademarks of Keithley
Instruments, LLC. Other brand names are trademarks or registered trademarks of their respective
holders.
Microsoft, Visual C++, Excel, and Windows are either registered trademarks or trademarks of
Microsoft Corporation in the United States and/or other countries.
Document number: 077114601 / March 2019

Safety precautions
The following safety precautions should be observed before using this product and any associated instrumentation. Although
some instruments and accessories would normally be used with nonhazardous voltages, there are situations where hazardous
conditions may be present.
This product is intended for use by personnel who recognize shock hazards and are familiar with the safety precautions required
to avoid possible injury. Read and follow all installation, operation, and maintenance information carefully before using the
product. Refer to the user documentation for complete product specifications.
If the product is used in a manner not specified, the protection provided by the product warranty may be impaired.
The types of product users are:
Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring that the
equipment is operated within its specifications and operating limits, and for ensuring that operators are adequately trained.
Operators use the product for its intended function. They must be trained in electrical safety procedures and proper use of the
instrument. They must be protected from electric shock and contact with hazardous live circuits.
Maintenance personnel perform routine procedures on the product to keep it operating properly, for example, setting the line
voltage or replacing consumable materials. Maintenance procedures are described in the user documentation. The procedures
explicitly state if the operator may perform them. Otherwise, they should be performed only by service personnel.
Service personnel are trained to work on live circuits, perform safe installations, and repair products. Only properly trained
service personnel may perform installation and service procedures.
Keithley products are designed for use with electrical signals that are measurement, control, and data I/O connections, with low
transient overvoltages, and must not be directly connected to mains voltage or to voltage sources with high transient
overvoltages. Measurement Category II (as referenced in IEC 60664) connections require protection for high transient
overvoltages often associated with local AC mains connections. Certain Keithley measuring instruments may be connected to
mains. These instruments will be marked as category II or higher.
Unless explicitly allowed in the specifications, operating manual, and instrument labels, do not connect any instrument to mains.
Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or test
fixtures. The American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels greater than
30 V RMS, 42.4 V peak, or 60 VDC are present. A good safety practice is to expect that hazardous voltage is present in any
unknown circuit before measuring.
Operators of this product must be protected from electric shock at all times. The responsible body must ensure that operators
are prevented access and/or insulated from every connection point. In some cases, connections must be exposed to potential
human contact. Product operators in these circumstances must be trained to protect themselves from the risk of electric shock. If
the circuit is capable of operating at or above 1000 V, no conductive part of the circuit may be exposed.
Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance-limited
sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective
devices to limit fault current and voltage to the card.
Before operating an instrument, ensure that the line cord is connected to a properly-grounded power receptacle. Inspect the
connecting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use.
When installing equipment where access to the main power cord is restricted, such as rack mounting, a separate main input
power disconnect device must be provided in close proximity to the equipment and within easy reach of the operator.
For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under
test. ALWAYS remove power from the entire test system and discharge any capacitors before: connecting or disconnecting
cables or jumpers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers.
Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth)
ground. Always make measurements with dry hands while standing on a dry, insulated surface capable of withstanding the
voltage being measured.

For safety, instruments and accessories must be used in accordance with the operating instructions. If the instruments or
accessories are used in a manner not specified in the operating instructions, the protection provided by the equipment may be
impaired.
Do not exceed the maximum signal levels of the instruments and accessories. Maximum signal levels are defined in the
specifications and operating information and shown on the instrument panels, test fixture panels, and switching cards.
When fuses are used in a product, replace with the same type and rating for continued protection against fire hazard.
Chassis connections must only be used as shield connections for measuring circuits, NOT as protective earth (safety ground)
connections.
If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation requires the use
of a lid interlock.
If a screw is present, connect it to protective earth (safety ground) using the wire recommended in the user documentation.
The symbol on an instrument means caution, risk of hazard. The user must refer to the operating instructions located in the
user documentation in all cases where the symbol is marked on the instrument.
The symbol on an instrument means warning, risk of electric shock. Use standard safety precautions to avoid personal
contact with these voltages.
The symbol on an instrument shows that the surface may be hot. Avoid personal contact to prevent burns.
The symbol indicates a connection terminal to the equipment frame.
If this symbol is on a product, it indicates that mercury is present in the display lamp. Please note that the lamp must be
properly disposed of according to federal, state, and local laws.
The WARNING heading in the user documentation explains hazards that might result in personal injury or death. Always read
the associated information very carefully before performing the indicated procedure.
The CAUTION heading in the user documentation explains hazards that could damage the instrument. Such damage may
invalidate the warranty.
The CAUTION heading with the symbol in the user documentation explains hazards that could result in moderate or minor
injury or damage the instrument. Always read the associated information very carefully before performing the indicated
procedure. Damage to the instrument may invalidate the warranty.
Instrumentation and accessories shall not be connected to humans.
Before performing any maintenance, disconnect the line cord and all test cables.
To maintain protection from electric shock and fire, replacement components in mains circuits —including the power
transformer, test leads, and input jacks —must be purchased from Keithley. Standard fuses with applicable national safety
approvals may be used if the rating and type are the same. The detachable mains power cord provided with the instrument may
only be replaced with a similarly rated power cord. Other components that are not safety-related may be purchased from other
suppliers as long as they are equivalent to the original component (note that selected parts should be purchased only through
Keithley to maintain accuracy and functionality of the product). If you are unsure about the applicability of a replacement
component, call a Keithley office for information.
Unless otherwise noted in product-specific literature, Keithley instruments are designed to operate indoors only, in the following
environment: Altitude at or below 2,000 m (6,562 ft); temperature 0 °C to 50 °C (32 °F to 122 °F); and pollution degree 1 or 2.
To clean an instrument, use a cloth dampened with deionized water or mild, water-based cleaner. Clean the exterior of the
instrument only. Do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Products that
consist of a circuit board with no case or chassis (e.g., a data acquisition board for installation into a computer) should never
require cleaning if handled according to instructions. If the board becomes contaminated and operation is affected, the board
should be returned to the factory for proper cleaning/servicing.
Safety precaution revision as of June 2017.

Introduction..............................................................................................................1-1
Welcome.............................................................................................................................. 1-1
Extended warranty............................................................................................................... 1-1
Contact information.............................................................................................................. 1-2
Product documentation and drivers ..................................................................................... 1-2
Organization of manual sections.......................................................................................... 1-3
Key features......................................................................................................................... 1-4
Standard accessories........................................................................................................... 1-5
Optional accessories............................................................................................................ 1-6
Available services ................................................................................................................ 1-6
General ratings..................................................................................................................... 1-7
Terminology in this manual.................................................................................................. 1-7
General operation ....................................................................................................2-1
Front-panel overview............................................................................................................ 2-1
Rear-panel overview............................................................................................................ 2-3
Front-panel user interface.................................................................................................... 2-4
Startup screen........................................................................................................................... 2-4
Home screens...........................................................................................................................2-4
Power supply menu overview..................................................................................................2-19
Battery test menu overview.....................................................................................................2-32
Battery simulator menu overview............................................................................................2-42
Adjusting the backlight brightness and timer...........................................................................2-51
Installing the system........................................................................................................... 2-52
Bumpers..................................................................................................................................2-52
Dimensions .............................................................................................................................2-53
Power the instrument on and off ............................................................................................. 2-58
Test connections................................................................................................................ 2-61
Front-panel connector.............................................................................................................2-62
Rear-panel output mating connector.......................................................................................2-63
Two-wire local sense connection ............................................................................................2-63
Four-wire sense connection....................................................................................................2-64
Open leads detection..............................................................................................................2-66
Reversed sense leads.............................................................................................................2-67
Remote communications interfaces................................................................................... 2-68
Supported remote interfaces...................................................................................................2-69
GPIB communications.............................................................................................................2-69
LAN communications..............................................................................................................2-72
USB communications..............................................................................................................2-88
How to install the Keithley I/O Layer .......................................................................................2-92
Set voltage and current limit .............................................................................................. 2-93
Constant voltage (CV) and constant current (CC) mode.........................................................2-94
Select a measurement function ......................................................................................... 2-96
Table of contents

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual
Power supply...........................................................................................................................2-96
Battery test..............................................................................................................................2-97
Battery simulator.....................................................................................................................2-97
Select a specific measurement range................................................................................ 2-97
Selecting a specific measurement range ................................................................................2-98
Using autoranging for current measurements.........................................................................2-99
Protection......................................................................................................................... 2-100
Overvoltage protection..........................................................................................................2-101
Overcurrent protection ..........................................................................................................2-102
Overtemperature protection ..................................................................................................2-103
Overprotection error..............................................................................................................2-103
Maximum voltage limits.........................................................................................................2-104
Saving setups................................................................................................................... 2-105
Save a user setup.................................................................................................................2-105
Recall a user setup ...............................................................................................................2-106
Specify a default setup..........................................................................................................2-107
Using the event log .......................................................................................................... 2-107
Information provided for each event log entry.......................................................................2-107
Save the event log to an external flash drive ........................................................................2-108
Clear the event log................................................................................................................2-108
System information .......................................................................................................... 2-108
Instrument sounds............................................................................................................ 2-109
Resets.............................................................................................................................. 2-109
Reset the instrument.............................................................................................................2-110
Reset default values..............................................................................................................2-110
Functions and features............................................................................................ 3-1
Instrument access................................................................................................................ 3-1
Changing the instrument access mode.....................................................................................3-2
Changing the password ............................................................................................................3-2
Graph ................................................................................................................................... 3-3
Changing the window position and zoom..................................................................................3-3
Adjusting the scale and offset of the Y-axis ..............................................................................3-4
Graphing the battery test function.............................................................................................3-6
Graphing the battery simulation function...................................................................................3-7
Output delay, slew rate, and source delay........................................................................... 3-8
Output delay..............................................................................................................................3-8
Slew rate...................................................................................................................................3-9
Source delay...........................................................................................................................3-10
Data buffer ......................................................................................................................... 3-11
Effects of reset and power cycle on buffer .............................................................................. 3-11
Buffer fill status........................................................................................................................3-12
Setting reading buffer size and buffer mode............................................................................3-12
Viewing and saving buffer content ..........................................................................................3-14
Configuring the statistics applied to data in the buffer.............................................................3-18
Clearing the buffer................................................................................................................... 3-21
Automatically clearing a buffer................................................................................................3-21
Digital I/O ........................................................................................................................... 3-22
Digital I/O port.........................................................................................................................3-22
Configuring digital I/O lines .....................................................................................................3-27
Trigger model..................................................................................................................... 3-30

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents
Idle and initiate........................................................................................................................3-31
Arm layer................................................................................................................................. 3-31
Trigger layer............................................................................................................................3-31
Source, source delay, and measure actions ...........................................................................3-32
Counter ...................................................................................................................................3-32
Meter complete .......................................................................................................................3-32
Running the trigger model.......................................................................................................3-33
Level trigger ....................................................................................................................... 3-35
Configuring a voltage level trigger...........................................................................................3-35
Configuring a current level trigger...........................................................................................3-37
List operation...................................................................................................................... 3-39
Configuring a list .....................................................................................................................3-40
Importing a list from an external USB flash drive ....................................................................3-42
Exporting a list to an external USB flash drive ........................................................................3-43
Configuring and running a list..................................................................................................3-43
Aborting a list ..........................................................................................................................3-53
Sink operation.................................................................................................................... 3-54
Battery test......................................................................................................................... 3-55
Battery charging and discharging............................................................................................3-56
Battery discharging test...........................................................................................................3-57
Battery charging test ...............................................................................................................3-59
Generating and editing a battery model ..................................................................................3-60
ESR measurement..................................................................................................................3-63
A-H measurement...................................................................................................................3-66
Capacitance measurement .....................................................................................................3-69
Battery simulation............................................................................................................... 3-70
Battery simulation settings ......................................................................................................3-70
Simulating a battery ................................................................................................................ 3-71
Measurement optimization......................................................................................4-1
Introduction .......................................................................................................................... 4-1
Optimizing either measurement accuracy or speed ............................................................ 4-1
Resolution................................................................................................................................. 4-2
NPLC ........................................................................................................................................4-4
Autozero measurements...........................................................................................................4-5
Displayed digits......................................................................................................................... 4-6
Filtering measurement data....................................................................................................... 4-7
Math calculations that you can apply to measurements.................................................... 4-11
mx+b.......................................................................................................................................4-11
Setting mx+b math operations ................................................................................................4-12
Relative offset .................................................................................................................... 4-13
Establishing a relative offset value..........................................................................................4-13
Displayed measurements................................................................................................... 4-15
Select the source of readings..................................................................................................4-17
ESR measurement............................................................................................................. 4-18
Introduction to the ESR measurement....................................................................................4-18
Measuring ESR in the battery test function.............................................................................4-20
A-H measurement.............................................................................................................. 4-21
Introduction to the A-H measurement .....................................................................................4-21
Measuring A-H in the battery test function..............................................................................4-22

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual
Application examples ..............................................................................................5-1
Simple voltage output and current measurement................................................................ 5-1
Equipment required...................................................................................................................5-1
Set up remote communications.................................................................................................5-1
Device connections...................................................................................................................5-2
Set the voltage and current limit................................................................................................5-2
Configure and execute a 10-step linear list sweep.............................................................. 5-3
Equipment required...................................................................................................................5-3
Set up remote communications.................................................................................................5-4
Device connections...................................................................................................................5-4
Configure a 10-step linear list sweep ........................................................................................5-4
Execute a 10-step linear list sweep...........................................................................................5-6
Perform a fast current load measurement ........................................................................... 5-7
Equipment required...................................................................................................................5-7
Set up remote communications.................................................................................................5-8
Device connections...................................................................................................................5-8
Measure the fast current load changes...................................................................................5-10
Battery test......................................................................................................................... 5-13
Equipment required.................................................................................................................5-13
Device connections.................................................................................................................5-13
Test a battery and generate a battery model...........................................................................5-13
Battery simulation test........................................................................................................ 5-16
Equipment required.................................................................................................................5-16
Device connections.................................................................................................................5-16
Simulate a battery with the 2281S........................................................................................... 5-17
Explanations of the test...........................................................................................................5-18
Introduction to SCPI commands.............................................................................6-1
Introduction to SCPI............................................................................................................. 6-1
Command messages ................................................................................................................6-1
Command execution rules.........................................................................................................6-2
SCPI command programming notes.................................................................................... 6-2
SCPI command formatting........................................................................................................6-2
Using the SCPI command reference.........................................................................................6-5
SCPI command reference........................................................................................7-1
Common commands............................................................................................................ 7-1
*CLS..........................................................................................................................................7-2
*ESE .........................................................................................................................................7-3
*ESR? .......................................................................................................................................7-4
*IDN? ........................................................................................................................................7-4
*LANG?.....................................................................................................................................7-5
*OPC.........................................................................................................................................7-6
*RCL .........................................................................................................................................7-6
*RST .........................................................................................................................................7-7
*SAV .........................................................................................................................................7-7
*SRE .........................................................................................................................................7-8
*STB?........................................................................................................................................7-9
*TRG.........................................................................................................................................7-9
*TST?......................................................................................................................................7-10
*WAI........................................................................................................................................7-10
:ABORt[n]................................................................................................................................7-12

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents
:CONFigure[n]:<function> .......................................................................................................7-13
:ENTRy[n]:FUNCtion...............................................................................................................7-14
:FETCh[n]?..............................................................................................................................7-15
:FORCe:TRIGger....................................................................................................................7-16
:FORMat:ELEMents................................................................................................................7-17
:MEASure[n]:<function>?........................................................................................................7-18
:READ[n]?............................................................................................................................... 7-20
ARM subsystem................................................................................................................. 7-21
:ARM[:SEQuence[n]]:COUNt ..................................................................................................7-21
:ARM[:SEQuence[n]]:SOURce................................................................................................7-22
BATTery subsystem........................................................................................................... 7-23
:BATTery[n]:DATA:CLEar .......................................................................................................7-23
:BATTery[n]:DATA:DATA?......................................................................................................7-23
:BATTery[n]:DATA:DATA:SELected? .....................................................................................7-25
:BATTery[n]:DATA:SAVE........................................................................................................7-26
:BATTery:DIGital:LINE<line_index>:CONFigure.....................................................................7-27
:BATTery:DIGital:LINE<n>:EDGe...........................................................................................7-28
:BATTery:DIGital:LINE<n>:MANual:INPut:DATA?.................................................................. 7-28
:BATTery[n]:MODel:LOAD:USB..............................................................................................7-29
:BATTery[n]:MODel<modelindex>:<element>.........................................................................7-30
:BATTery[n]:MODel<modelindex>:<element>:APPend ..........................................................7-31
:BATTery[n]:MODel<modelindex>:<element>:SIMPlify ..........................................................7-32
:BATTery[n]:MODel<modelindex>:<element>:STEPs? ..........................................................7-33
:BATTery[n]:MODel<modelindex>:ROW<rowindex>..............................................................7-34
:BATTery[n]:MODel:RCL......................................................................................................... 7-35
:BATTery[n]:MODel:SAVE:INTernal........................................................................................7-36
:BATTery[n]:MODel:SAVE:USB.............................................................................................. 7-37
:BATTery[n]:SIMulator:CAPacity?...........................................................................................7-37
:BATTery[n]:SIMulator:CAPacity:LIMit ....................................................................................7-38
:BATTery[n]:SIMulator:CURRent? ..........................................................................................7-39
:BATTery[n]:SIMulator:CURRent:LIMit....................................................................................7-39
:BATTery[n]:SIMulator:CURRent:PROTection[:LEVel] ...........................................................7-40
:BATTery[n]:SIMulator:HV.......................................................................................................7-41
:BATTery[n]:SIMulator:LV .......................................................................................................7-42
:BATTery[n]:SIMulator:METHod.............................................................................................. 7-43
:BATTery[n]:SIMulator:RESistance?.......................................................................................7-44
:BATTery[n]:SIMulator:RESistance:OFFSet............................................................................7-44
:BATTery[n]:SIMulator:SAMPle:INTerval ................................................................................7-45
:BATTery[n]:SIMulator:SOC....................................................................................................7-46
:BATTery[n]:SIMulator:TVOLtage? .........................................................................................7-47
:BATTery[n]:SIMulator:TVOLtage:PROTection[:LEVel] ..........................................................7-47
:BATTery[n]:SIMulator:VOC....................................................................................................7-48
:BATTery[n]:SIMulator:VOC:EMPTy .......................................................................................7-49
:BATTery[n]:SIMulator:VOC:FULL..........................................................................................7-50
:BATTery[n]:TEST:MEASure:EVOC? .....................................................................................7-51
:BATTery[n]:TEST:SENSe:AH:ESRInterval............................................................................7-51
:BATTery[n]:TEST:SENSe:AH:EXECute.................................................................................7-52
:BATTery[n]:TEST:SENSe:AH:GMODel:RANGe....................................................................7-52
:BATTery[n]:TEST:SENSe:AH:GMODel:SAVE:INTernal........................................................7-53
:BATTery[n]:TEST:SENSe:AH:GMODel:SAVE:USB ..............................................................7-54
:BATTery[n]:TEST:SENSe:AH:ILIMit ......................................................................................7-55
:BATTery[n]:TEST:SENSe:AH[:LEVel]?..................................................................................7-55
:BATTery[n]:TEST:SENSe:AH:VFULl .....................................................................................7-56
:BATTery[n]:TEST:SENSe:EVOC:DELAy...............................................................................7-56
:BATTery[n]:TEST:SENSe:SAMPle:INTerval..........................................................................7-57
:BATTery[n]:TEST[:SOURce]:CURRent:END.........................................................................7-58
:BATTery[n]:TEST[:SOURce]:CURRent:LIMit:SOURce..........................................................7-59
:BATTery[n]:TEST[:SOURce]:CURRent:PROTection[:LEVel].................................................7-60
:BATTery[n]:TEST[:SOURce]:HV............................................................................................ 7-61
:BATTery[n]:TEST[:SOURce]:LV ............................................................................................7-62

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual
:BATTery[n]:TEST[:SOURce]:VOLTage[:LEVel]..................................................................... 7-63
:BATTery[n]:TEST[:SOURce]:VOLTage:LIMit.........................................................................7-64
:BATTery[n]:TEST[:SOURce]:VOLTage:PROTection[:LEVel].................................................7-65
:BATTery[n]:TRACe:TRIGger:CURRent:DIRection.................................................................7-66
:BATTery[n]:TRACe:TRIGger:CURRent[:LEVel].....................................................................7-66
:BATTery[n]:TRACe:TRIGger:CURRent:STATe .....................................................................7-67
:BATTery[n]:TRACe:CLEar..................................................................................................... 7-67
:BATTery[n]:TRACe:DATA?....................................................................................................7-68
:BATTery[n]:TRACe:DATA:SELected?...................................................................................7-70
:BATTery[n]:TRACe:SAVE......................................................................................................7-71
:BATTery[n]:TRACe:TRIGger:OCCur? ...................................................................................7-72
:BATTery[n]:TRACe:TRIGger:OFFSet....................................................................................7-72
:BATTery[n]:TRACe:TRIGger:VOLTage:DIRection.................................................................7-73
:BATTery[n]:TRACe:TRIGger:VOLTage[:LEVel].....................................................................7-73
:BATTery[n]:TRACe:TRIGger:VOLTage:STATe.....................................................................7-74
:BATTery[n]:OUTPut:PROTection:CLEar ...............................................................................7-74
:BATTery[n]:OUTPut:PROTection:TRIPped?..........................................................................7-75
:BATTery[n]:OUTPut[:STATe].................................................................................................7-76
:BATTery[n]:STATus?.............................................................................................................7-76
CALCulate subsystem........................................................................................................ 7-77
:CALCulate[1]:<function>:FORMat..........................................................................................7-77
:CALCulate[1]:<function>:KMATh:MBFactor...........................................................................7-78
:CALCulate[1]:<function>:KMATh:MMFactor..........................................................................7-79
:CALCulate[1]:<function>:KMATh:MUNits...............................................................................7-80
:CALCulate[1]:<function>:STATe............................................................................................ 7-81
:CALCulate2:DATA?...............................................................................................................7-82
:CALCulate2:FORMat .............................................................................................................7-84
:CALCulate2:FORMat:ELEMents............................................................................................ 7-86
:CALCulate2:FUNCtion...........................................................................................................7-87
:CALCulate2:IMMediate..........................................................................................................7-88
:CALCulate2:STATe................................................................................................................7-90
CALibration subsystem...................................................................................................... 7-91
:CALibration:PROTected:CANCel........................................................................................... 7-91
:CALibration:PROTected:CODE .............................................................................................7-92
:CALibration:PROTected:COUNt?..........................................................................................7-92
:CALibration:PROTected:DATA?............................................................................................7-93
:CALibration:PROTected:DATE..............................................................................................7-93
:CALibration:PROTected[:DC[n]]:STEP<step> .......................................................................7-94
:CALibration:PROTected[:DC[n]]:STEP<step>:DATA.............................................................7-96
:CALibration:PROTected:SAVE..............................................................................................7-98
:CALibration:PROTected:STATe............................................................................................. 7-99
Digital subsystem............................................................................................................. 7-100
:DIGital:LINE<n>:FUNCtion ..................................................................................................7-100
:DIGital:LINE<n>:MANual:INPut:DATA?...............................................................................7-101
DISPlay subsystem.......................................................................................................... 7-102
:DISPlay:BRIGhtness............................................................................................................7-102
:DISPlay:CLEar.....................................................................................................................7-103
:DISPlay:SCREen.................................................................................................................7-103
:DISPlay:USER:TEXT[:DATA]...............................................................................................7-104
INITiate subsystem .......................................................................................................... 7-105
:INITiate[n]:CONTinuous.......................................................................................................7-105
:INITiate[n][:IMMediate].........................................................................................................7-106
MMEMory subsystem....................................................................................................... 7-106
:MMEMory:LOAD:SETup......................................................................................................7-106
:MMEMory:SAVE:SETup ......................................................................................................7-107
OUTPut subsystem.......................................................................................................... 7-108

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents
:OUTPut:DELay:FALLing......................................................................................................7-108
:OUTPut:DELay:RISing.........................................................................................................7-109
:OUTPut:DELay:STATe ........................................................................................................7-110
:OUTPut:PROTection:CLEar.................................................................................................7-111
:OUTPut:PROTection:TRIPped?[<channel>]........................................................................7-112
:OUTPut[:STATe]..................................................................................................................7-113
SENSe subsystem........................................................................................................... 7-114
:SENSe[n]:FUNCtion.............................................................................................................7-114
:SENSe[n]:<function>:AVERage:COUNt ..............................................................................7-115
:SENSe[n]:<function>:AVERage[:STATe].............................................................................7-116
:SENSe[n]:<function>:AVERage:TCONtrol...........................................................................7-117
:SENSe[n]:<function>:AVERage:WINDow............................................................................7-118
:SENSe[n]:<function>:DIGits.................................................................................................7-119
:SENSe[n]:<function>:NPLCycles.........................................................................................7-120
:SENSe[n]:<function>:RANGe ..............................................................................................7-121
:SENSe[n]:<function>:RANGe:AUTO ...................................................................................7-122
:SENSe[n]:<function>:REFerence......................................................................................... 7-123
:SENSe[n]:<function>:REFerence:ACQuire..........................................................................7-124
:SENSe[n]:<function>:REFerence:STATe ............................................................................7-125
:SENSe[n]:<function>:RESolution.........................................................................................7-126
SOURce subsystem......................................................................................................... 7-127
[:SOURce[n]]:DELay.............................................................................................................7-127
[:SOURce[n]]:DELay:STATe................................................................................................. 7-128
[:SOURce[n]]:<function>:PROTection[:LEVel] ......................................................................7-129
[:SOURce[n]]:<function>[:LEVel][:IMMediate][:AMPLitude]...................................................7-130
[:SOURce[n]]:VOLTage:LIMit[:AMPLitude] ...........................................................................7-131
[:SOURce[n]]:VOLTage:SLEW:RISing..................................................................................7-132
[:SOURce[n]]:VOLTage:SLEW:FALLing ...............................................................................7-133
[:SOURce[n]]:LIST<listNumber>:<element> .........................................................................7-134
[:SOURce[n]]:LIST<listNumber>:<element>:APPend...........................................................7-135
[:SOURce[n]]:LIST<listNumber>:<element>:POINts?...........................................................7-136
[:SOURce[n]]:LIST:END:ZERO.............................................................................................7-137
[:SOURce[n]]:LIST:HTIMe.....................................................................................................7-137
[:SOURce[n]]:LIST:LOAD:USB .............................................................................................7-138
[:SOURce[n]]:LIST:MCOMPlete............................................................................................ 7-139
[:SOURce[n]]:LIST:RCL ........................................................................................................7-140
[:SOURce[n]]:LIST:SAVE:INTernal.......................................................................................7-143
[:SOURce[n]]:LIST:SAVE:USB..............................................................................................7-144
[:SOURce[n]]:LIST:STATe ....................................................................................................7-145
STATus subsystem.......................................................................................................... 7-148
:STATus:MEASurement[:EVENt]?........................................................................................7-148
:STATus:MEASurement:ENABle ..........................................................................................7-148
:STATus:MEASurement:INSTrument[:EVENt]?....................................................................7-149
:STATus:MEASurement:INSTrument:ENABle......................................................................7-149
:STATus:MEASurement:INSTrument:ISUMmary[:EVENt]?..................................................7-150
:STATus:MEASurement:INSTrument:ISUMmary:ENABle ....................................................7-151
:STATus:MEASurement:INSTrument:ISUMmary:CONDition?..............................................7-152
:STATus:OPERation[:EVENt]?..............................................................................................7-152
:STATus:OPERation:ENABle................................................................................................7-153
:STATus:OPERation:INSTrument[:EVENt]? .........................................................................7-153
:STATus:OPERation:INSTrument:ENABle ...........................................................................7-154
:STATus:OPERation:INSTrument:ISUMmary[:EVENt]? .......................................................7-154
:STATus:OPERation:INSTrument:ISUMmary:ENABle..........................................................7-155
:STATus:OPERation:INSTrument:ISUMmary:CONDition?...................................................7-156
:STATus:PRESet ..................................................................................................................7-156
:STATus:QUEStionable[:EVENt]?.........................................................................................7-157
:STATus:QUEStionable:ENABle........................................................................................... 7-158
:STATus:QUEStionable:INSTrument[:EVENt]?.....................................................................7-158
:STATus:QUEStionable:INSTrument:ENABle.......................................................................7-159

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual
:STATus:QUEStionable:INSTrument:ISUMmary[:EVENt]?................................................... 7-160
:STATus:QUEStionable:INSTrument:ISUMmary:ENABle.....................................................7-160
:STATus:QUEStionable:INSTrument:ISUMmary:CONDition? ..............................................7-161
SYSTem subsystem......................................................................................................... 7-162
:SYSTem:AZERo[n][:STATe]................................................................................................7-162
:SYSTem:BEEPer:ERRor[:STATe].......................................................................................7-163
:SYSTem:COMMunication:ABORt........................................................................................7-163
:SYSTem:COMMunication:LAN:CONFigure.........................................................................7-164
:SYSTem:COMMunication:LAN:MACaddress?.....................................................................7-165
:SYSTem:DATE....................................................................................................................7-166
:SYSTem:ERRor?.................................................................................................................7-166
:SYSTem:ERRor:CLEar........................................................................................................7-167
:SYSTem:ERRor:CODE?......................................................................................................7-167
:SYSTem:ERRor:COUNt?.....................................................................................................7-168
:SYSTem:EVENtlog:SAVE....................................................................................................7-168
:SYSTem:GPIB:ADDRess.....................................................................................................7-169
:SYSTem:KCLick ..................................................................................................................7-170
:SYSTem:LOCal....................................................................................................................7-170
:SYSTem:LFRequency? .......................................................................................................7-171
:SYSTem:PASSword:LOCK..................................................................................................7-171
:SYSTem:PASSword:MODE.................................................................................................7-172
:SYSTem:PASSword:NEW...................................................................................................7-173
:SYSTem:PASSword:UNLock...............................................................................................7-174
:SYSTem:POSetup:STATe...................................................................................................7-174
:SYSTem:PRESet.................................................................................................................7-175
:SYSTem:RWLock................................................................................................................7-176
:SYSTem:TIME.....................................................................................................................7-176
:SYSTem:VERSion?.............................................................................................................7-177
TRACe subsystem........................................................................................................... 7-177
:DATA[n]:CLEar ....................................................................................................................7-177
:DATA[n]:CLEar:AUTO .........................................................................................................7-178
:DATA[n]:DATA?...................................................................................................................7-178
:DATA[n]:DATA:SELected?...................................................................................................7-180
:DATA[n]:FEED.....................................................................................................................7-182
:DATA[n]:FEED:CONTrol......................................................................................................7-183
:DATA[n]:POINts...................................................................................................................7-184
:DATA[n]:POINts:ACTual?....................................................................................................7-184
:DATA[n]:SAVE..................................................................................................................... 7-185
:TRACe[n]:CLEar..................................................................................................................7-186
:TRACe[n]:CLEar:AUTO .......................................................................................................7-186
:TRACe[n]:DATA?.................................................................................................................7-187
:TRACe[n]:DATA:SELected? ................................................................................................7-188
:TRACe[n]:FEED................................................................................................................... 7-190
:TRACe[n]:FEED:CONTrol....................................................................................................7-191
:TRACe[n]:POINts.................................................................................................................7-192
:TRACe[n]:POINts:ACTual?..................................................................................................7-192
:TRACe[n]:SAVE................................................................................................................... 7-193
:TRACe[n]:TRIGger:CURRent:DIRection..............................................................................7-194
:TRACe[n]:TRIGger:CURRent[:LEVel] ............................................................................ 7-194
:TRACe[n]:TRIGger:CURRent:STATe ..................................................................................7-195
:TRACe[n]:TRIGger:OCCur?.................................................................................................7-195
:TRACe[n]:TRIGger:OFFSet................................................................................................. 7-196
:TRACe[n]:TRIGger:VOLTage:DIRection..............................................................................7-196
:TRACe[n]:TRIGger:VOLTage[:LEVel]..................................................................................7-197
:TRACe[n]:TRIGger:VOLTage:STATe ..................................................................................7-197
TRIGger subsystem......................................................................................................... 7-198
:TRIGger[:SEQuence[n]]:COUNt...........................................................................................7-198
:TRIGger[:SEQuence[n]]:SAMPle:COUNt.............................................................................7-199

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents
:TRIGger[:SEQuence[n]]:SOURce........................................................................................7-200
Troubleshooting guide ............................................................................................8-1
Introduction .......................................................................................................................... 8-1
Contacting support............................................................................................................... 8-1
What to do if the power supply does not turn on ................................................................. 8-2
LAN troubleshooting suggestions ........................................................................................ 8-3
Error summary ..................................................................................................................... 8-3
Next steps.................................................................................................................9-1
Additional 2281S information............................................................................................... 9-1
Maintenance.............................................................................................................A-1
Introduction ..........................................................................................................................A-1
Line fuse replacement..........................................................................................................A-1
Upgrading the firmware........................................................................................................A-2
From the front panel..................................................................................................................A-3
Perform DIN VDE 701 test...................................................................................................A-4
Cleaning the front-panel display ..........................................................................................A-4
Verification ...............................................................................................................B-1
Overview ..............................................................................................................................B-1
Test record...........................................................................................................................B-1
DC voltage setting accuracy with remote sense........................................................................B-3
DC voltage setting accuracy without remote sense...................................................................B-4
DC voltage readback accuracy with remote sense ...................................................................B-5
DC voltage readback accuracy without remote sense ..............................................................B-6
DC voltage line regulation without remote sense......................................................................B-6
DC voltage load regulation without remote sense.....................................................................B-6
DC overvoltage protection.........................................................................................................B-7
Maximum continuous average sink current...............................................................................B-7
Sink current readback accuracy (1 A range).............................................................................B-8
Sink current readback accuracy (10 mA range)........................................................................B-8
Sink current readback accuracy (100 mA range)......................................................................B-9
DC current accuracy ...............................................................................................................B-10
DC current readback accuracy (10 A range)...........................................................................B-11
DC current readback accuracy (1 A range).............................................................................B-11
DC current readback accuracy (10 mA range)........................................................................B-12
DC current readback accuracy (100 mA range)......................................................................B-12
DC current line regulation........................................................................................................B-13
DC current load regulation ......................................................................................................B-13
DC overcurrent protection.......................................................................................................B-13
Voltage noise at 20 MHz.........................................................................................................B-14
Current noise at 20 MHz.........................................................................................................B-14
Performance verification procedures .................................................................................B-15
Performance verification conditions ........................................................................................B-15
Required equipment................................................................................................................B-16
Check DC voltage setting readback accuracy with remote sense...........................................B-16

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual
Check DC voltage setting accuracy without remote sense .....................................................B-19
Check DC voltage readback accuracy without remote sense .................................................B-21
Check DC voltage line regulation............................................................................................B-23
Check DC voltage load regulation...........................................................................................B-25
Check DC overvoltage protection............................................................................................B-26
Check sink current capability...................................................................................................B-27
Check sink current readback accuracy (1 A range).................................................................B-28
Check sink current readback accuracy (100 mA and 10 mA ranges)......................................B-30
Check DC current accuracy ....................................................................................................B-32
Check DC current readback accuracy (10 A and 1 A ranges).................................................B-34
Check DC current readback accuracy (100 mA and 10 mA ranges).......................................B-36
Check DC current line regulation ............................................................................................B-38
Check DC current load regulation...........................................................................................B-40
Check overcurrent protection..................................................................................................B-41
Check voltage noise (20 MHz)................................................................................................B-42
Check current noise (20 MHz).................................................................................................B-44
Calibration and adjustment.....................................................................................C-1
Overview ..............................................................................................................................C-1
Environmental conditions.....................................................................................................C-1
Warmup period..........................................................................................................................C-2
Line power.................................................................................................................................C-2
Calibration considerations....................................................................................................C-2
Calibration cycle........................................................................................................................C-2
Required equipment..................................................................................................................C-3
Characterization shunts ............................................................................................................C-4
Calibration connection..........................................................................................................C-6
Voltage calibration connections.................................................................................................C-7
Current calibration connections.................................................................................................C-8
Sink current calibration connections........................................................................................C-11
Front-panel calibration procedure......................................................................................C-12
Voltage calibration...................................................................................................................C-12
Low-current calibration............................................................................................................C-13
High-current calibration...........................................................................................................C-15
Low-sink current calibration.....................................................................................................C-16
High-sink current calibration....................................................................................................C-18
Saving calibration constants from the front panel....................................................................C-19
Remote calibration procedure............................................................................................C-20
Remote voltage calibration......................................................................................................C-21
Remote low-current calibration................................................................................................C-22
Remote high-current calibration..............................................................................................C-23
Remote low-sink current calibration........................................................................................C-25
Remote high-sink-current calibration.......................................................................................C-27
Saving calibration constants using SCPI commands..............................................................C-28
Configure the calibration date .................................................................................................C-29
Exit the calibration procedure using SCPI commands ............................................................C-29
Change the calibration password.......................................................................................C-30
Calibration constants..........................................................................................................C-31
Status model ............................................................................................................D-1
Overview ..............................................................................................................................D-1
Status model structure ..............................................................................................................D-3

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents
Programming and reading registers.....................................................................................D-5
Programming enable registers..................................................................................................D-5
Reading the registers................................................................................................................D-6
Clearing the registers...........................................................................................................D-6
Status byte and service request...........................................................................................D-7
Status Byte Register .................................................................................................................D-7
Service Request Enable Register .............................................................................................D-8
Status register sets ..............................................................................................................D-9
Register bit descriptions............................................................................................................D-9
Event registers........................................................................................................................D-20
Event enable registers ............................................................................................................D-20
Condition registers..................................................................................................................D-20
Queues...............................................................................................................................D-20
Output queue ..........................................................................................................................D-20
Error queue.............................................................................................................................D-21
Serial polling and SRQ.......................................................................................................D-21
Status model programming examples ...............................................................................D-22
SRQ when reading buffer becomes full...................................................................................D-22
SRQ when trigger model is finished........................................................................................D-23

In this section:
Welcome.................................................................................. 1-1
Extended warranty................................................................... 1-1
Contact information.................................................................. 1-2
Product documentation and drivers.......................................... 1-2
Organization of manual sections.............................................. 1-3
Key features............................................................................. 1-4
Standard accessories............................................................... 1-5
Optional accessories................................................................ 1-6
Available services .................................................................... 1-6
General ratings......................................................................... 1-7
Terminology in this manual ...................................................... 1-7
Welcome
Thank you for choosing a Keithley Instruments product. The 2281S Precision DC Power Supply and
Battery Simulator is a high-sensitivity, low-noise, programmable instrument that sources stable,
low-noise voltage and can monitor load currents over a wide dynamic range, from amperes to
nanoamperes.
In addition to serving as a power supply, it can conduct battery testing by charging and discharging
the battery under test and creating a model for the battery. The 2281S can also simulate batteries to
facilitate tests conducted on the products supplied by batteries.
The high-resolution, 4.3-inch TFT color display presents numerous parameters that describe the state
of the instrument to enable you to get the most information from your measurements.
Extended warranty
Additional years of warranty coverage are available on many products. These valuable contracts
protect you from unbudgeted service expenses and provide additional years of protection at a fraction
of the price of a repair. Extended warranties are available on new and existing products. Contact your
local Keithley Instruments office, sales partner, or distributor for details.
Section 1
Introduction

Section 1: Introduction Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual
1-2 077114601 / March 2019
Contact information
If you have any questions after you review the information in this documentation, please contact your
local Keithley Instruments office, sales partner, or distributor. You can also call the corporate
headquarters of Keithley Instruments (toll-free inside the U.S. and Canada only) at 1-800-935-5595,
or from outside the U.S. at [phone]. For worldwide contact numbers, visit the Keithley
Instruments website (tek.com/keithley).
Product documentation and drivers
The following documentation and drivers for the 2281S are available for download from the Keithley
Instruments support website (tek.com/support).
Quick Start Guide: Provides unpacking instructions, describes basic connections, reviews basic
operation information, and provides a quick test procedure to ensure the instrument is
operational.
Reference Manual: Includes advanced operation topics, maintenance information,
troubleshooting procedures, and in-depth descriptions of programming commands.
Accessories information: Documentation for accessories that are available for the 2281S.
Drivers and release notes: IVI Instrument Driver, National Instruments LabVIEW™ driver, and
related release notes.

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Section 1: Introduction
077114601 / March 2019 1-3
Organization of manual sections
The information in this manual is organized into the following major categories:
General operation: Describes the components of the instrument and basic operation.
Functions and features: Describes features and functions, such as measure operations, battery test,
battery simulation, list mode, reading buffers, triggering, the digital I/O port, graph function, output
delay, and slew rate.
Measurement optimization: Describes best practices and recommended procedures that can
increase measurement speed, accuracy, and sensitivity.
Application examples: Contains examples of several applications that you can use as a starting
point for your own application.
Introduction to SCPI commands: Describes how to control the instrument using SCPI commands.
SCPI command reference: Contains programming notes and an alphabetical listing of all SCPI
commands available for the 2281S.
Troubleshooting guide: Describes the event log and basic LAN troubleshooting.
Next steps: Contains sources of additional information.
Maintenance: Contains information about instrument maintenance, including line fuse replacement
and firmware upgrades.
Verification: Contains performance verification procedures.
Calibration and adjustment: Contains information about instrument calibration from the front panel
and using SCPI commands.
Status model: Describes the 2281S status model.

Section 1: Introduction Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual
1-4 077114601 / March 2019
Key features
The 2281S has three basic functions: High-performance power supply, battery test, and battery
simulation.
As a high-performance power supply:
High-current resolution and sensitivity to measure a wide range of load currents
6½-digit measurement resolution to enable a wide range of measurements on a single current range
Fast current measurements to test or study load current pulses as narrow as 100 μs
Linear mode, low noise output
As a battery test instrument:
Battery capacity test with charging and discharging functions
Battery charge and discharge process and data logging (voltage, current, resistance, and amp-hour
information)
Generate a battery model based on battery test results
Measure open-circuit voltage and resistance
As a battery simulator:
Simulate a real battery based on a battery model
Dynamic and static simulation mode to simulate battery output
Intuitive way to show battery capacity and battery voltage on home screen
Other features:
Color TFT display with icon-based and soft-key user interface
Data logging and analysis with graphical display and statistics for trend analysis
GPIB, USB-TMC, and LAN LXI interfaces for automated test development
Digital I/O for rich trigger functions
Direct parameter entry using the front-panel keypad, soft keys, or the navigation control
Front-panel USB-A connector for flash-drive support
Front and rear inputs with remote sense connections on the rear-panel connector
Overcurrent, overvoltage, and overtemperature protection
Compact, 2U, half rack, stackable form factor fits easily in a test rack
Model
Description
2281S-20-6
Precision-measurement DC power supply, 20 V, 6 A