Ametek Amrel PLA Series User manual

M470039-01 Rev-F www.powerandtest.com
PLA/PLW SERIES
Programmable DC Electronic Load
OperationManual
Thismanual covers models:
PLA (Air-Cooled)Series
PLW (Water-Cooled)Series

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About AMETEK
AMETEK Programmable Power, Inc., a Business Unit of AMETEK, Inc., is a global leader in the design and
manufacture of precision, programmable power supplies for R&D, test and measurement, process control,
power bus simulation and power conditioning applications across diverse industrial segments. From bench top
supplies to rack-mounted industrial power subsystems, AMETEK Programmable Power is the proud
manufacturer of AMREL, Elgar, Sorensen, California Instruments, and Power Ten brand power supplies.
AMETEK, Inc. is a leading global manufacturer of electronic instruments and electromechanical devices with
annualized sales of $5 billion. The Company has over 18,000 colleagues working at more than 150
manufacturing facilities and more than 80 sales and service centers in the United States and around the world.
Trademarks
AMETEK is a registered trademark of AMETEK, Inc.
Other trademarks, registered trademarks, and product names are the property of their respective owners and
are used herein for identification purposes only.
Notice of Copyright
PLW/PLA Series Operation Manual © May 2019 AMETEK Programmable Power, Inc. All rights reserved.
Exclusion for Documentation
UNLESS SPECIFICALLY AGREED TO IN WRITING, AMETEK PROGRAMMABLE POWER, INC. (“AMETEK”):
(a) MAKES NO WARRANTY AS TO THE ACCURACY, SUFFICIENCY OR SUITABILITY OF ANY TECHNICAL OR
OTHER INFORMATION PROVIDED IN ITS MANUALS OR OTHER DOCUMENTATION.
(b) ASSUMES NO RESPONSIBILITY OR LIABILITY FOR LOSSES, DAMAGES, COSTS OR EXPENSES, WHETHER
SPECIAL, DIRECT, INDIRECT, CONSEQUENTIAL OR INCIDENTAL, WHICH MIGHT ARISE OUT OF THE USE
OF SUCH INFORMATION. THE USE OF ANY SUCH INFORMATION WILL BE ENTIRELY AT THE USER’S
RISK, AND
(c) REMINDS YOU THAT IF THIS MANUAL IS IN ANY LANGUAGE OTHER THAN ENGLISH, ALTHOUGH STEPS
HAVE BEEN TAKEN TO MAINTAIN THE ACCURACY OF THE TRANSLATION, THE ACCURACY CANNOT BE
GUARANTEED. APPROVED AMETEK CONTENT IS CONTAINED WITH THE ENGLISH LANGUAGE VERSION,
WHICH IS POSTED AT WWW.POWERANDTEST.COM.
Date and Revision
November 2019 Revision F
Part Number
M470039-01
Contact Information
Telephone: [phone] (toll free in North America)
858 450 0085 (direct)
Fax: [phone]
Email: [e-mail]
[e-mail]
ppssupport.ppd@ametek.
Web: www.powerandtest.com

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

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

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TABLE OF CONTENTS
ONE: FEATURES AND OPERATION OVERVIEW 12
INTRODUCTION 12
PLW MODEL NUMBER DESCRIPTION 13
PLA MODEL NUMBER DESCRIPTION 13
FEATURES AND OPTIONS 13
GENERAL INFORMATION AND OPERATING NOTES 14
OPERATING MODES 14
PROGRAMMING MODE PARAMETERS 15
INPUT CONTROL 16
TRANSIENT OPERATION 16
TRIGGER OPERATION 17
PROTECTION FEATURES 18
FRONT PANEL OPERATION QUICK GUIDE 22
LCD STATUS ENUCIATOR 22
LCD DESCRIPTION 22
FRONT PANEL KEYPAD DESCRIPTION 23
HOT KEY DESCRIPTION 23
ENCODER OPERATION 24
MODE AND MENU NAVIGATION 25
FRONT PANEL MENU TREE 26
EXTERNAL PROGRAMMING PORT 31
INPUT VOLTAGE LIMIT 32
INPUT CURRENT LIMIT 32
INPUT POWER LIMIT 32
DIMENSIONAL DRAWING & DESCRIPTIONS 34
PLW 2U MODEL 34
PLA 2U MODEL 36
PLA 3U MODEL 38
PLW 4U MODEL 40
PLA 4U and 6U MODEL 42
TWO: INSTALLATION 44
INTRODUCTION 44
BASIC SET UP PROCEDURE 44
INSPECTION, CLEANNING, AND PACKAGING 44
RETURNING ELECTRONIC LOAD TO THE MANUFACTURER 45
PACKAGING FOR SHIPPING OR STORAGE 45
LOCATION, MOUNTING, AND VENTILATION 46
FUSE REPLACEMENT 46
AC INPUT POWER CONNECTION 47
AC INPUT CONNECTOR AND VOLTAGE SELECTION 47
AC INPUT CORD 48
LOAD WIRING 48
REAR PANEL INLET & OUTLET PIPE INSTALLATION 49
RECOMMENDED WATER PIPING INSTALLATION FOR PLW SERIES 50
COOLANT WITH ANTI-FREEZE (GLYCOL) PRECAUTIONS 51
LOAD WIRING LENGTH FOR OPERATION WITH SENSE LINES 52
NOISE AND IMPEDANCE EFFECTS 52
LOAD CONNECTIONS 52
INPUT TERMINAL 52
INPUT TERMINAL CONNECTOR 53

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LOCAL SENSE CONFIGURATION 53
REMOTE SENSE CONFIGURATION 54
PARALLEL CONNECTION 54
TRIGGER OPERATION 55
ZERO-VOLT LOADING CONNECTION 56
THREE: LOCAL OPERATION 57
INTRODUCTION 57
VOLTAGE AND CURRENT METERING INFORMATION 57
OPERATING STATUS INFORMATION 57
LOCAL AND GPIB OPERATION INFORMATION 58
MODE MENU OPERATION AND RANGE SETTING 58
MAIN LEVEL LOCAL OPERATION 59
ENCODER OPERATION 60
MENU FUNCTION 60
LOAD CONTROL MENU 63
STEP PARAMETERS 63
MEASURE SENSE 63
PORT 0 63
EXTERNAL CONTROL 64
SHORT CONTROL 65
CROSS MODE 65
CROSS RANGE 65
TRIGGER SOURCE 65
PROTECTION 65
V-ON PROTECTION (UVL) 65
MAX/MIN SETTING FUNCTION 66
CALIBRATION PARAMETERS 66
OSCILLATE 66
OSC DETECTION DISABLE AND DELAY FEATURES 66
BOOT INPUT 67
LOAD PROFILE MENU 67
DISPLAY MENU 67
C OPERAND FOR BATTERY TESTING 67
SYSTEM FUNCTIONS MENU 67
GPIB FUNCTION 67
RS-232 FUNCTION 68
SYNTAX MODE 68
EOS CODE 68
BUZZER 68
PANEL LOCK 68
ETHERNET FUNCTION 68
USB FUNCTION 70
AUTHENTICATE MENU 81
SERIAL NUMBER 81
INTERFACE 81
CODE 81
TRANSIENT OPERATION 81
TRANSIENT MODE 81
ENTERING TRANSIENT MODE VALUES 82
TRANSIENT FREQUENCY, SLEW RATE AND DUTY CYCLE PROGRAMMING 82
LOCAL TRANSIENT OPERATION 83
CONTINUOUS MODE 83
TOGGLE MODE 84
PULSE MODE 85
TRIGGER MODE 86
STEP MODE 87

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STEP OPERATION SET-UP 87
STEP FUNCTION 87
STEP COUNT 87
STEP MODE 87
ENTERING STEPPING MODE VALUE 88
FOUR: REMOTE OPERATION 90
INTRODUCTION 90
INTRODUCTION TO GPIB & RS-232 (SCPI) COMMANDS 90
OVERVIEW SCPI LANGUAGE 90
SYNTAX OVERVIEW 91
LANGUAGE DICTIONARY 91
COMMAND STRUCTURE 91
SCPI (GPIB & RS-232) COMMAND SET 92
COMMON COMMANDS 101
COMMAND LIST 102
FIVE: CALIBRATION 104
INTRODUCTION 104
CALIBRATION SERVICE ENVIRONMENT AND PRECAUTIONS 104
CALIBRATION REQUIRED EQUIPMENT 104
CALIBRATION CONFIGURATION 105
CALIBRATION PARAMETERS 105
LOCAL CALIBRATION PROCEDURES 106
RE-INSTALLING CALIBRATION DATA 112
SIX: NEWELOAD FEATURES 113
POWER INTERRUPTION 113
UNDER TEMPERATURE WARNING 114
INPUT CONTACTOR CONTROL 114
ULTRA-LOW RANGE OPTION 115
STEP MODE MODIFICATION 117
OSC RANGE SELECTION 119
INTERLOCK FUNCTION 120
STEP TIME UNIT 121
OVERPOWER WARNING MESSAGE 121
PV SWEEP FUNCTION 122
MASTER-SLAVE PARALLEL OPERATION 126
REMOTE INHIBIT 130
SEVEN: SPECIFICATION AND POWER CURVE 131
COMMON SPECIFICATIONS 131
PLA POWER CURVES 133
PLW POWER CURVES 134
APPENDIX A: PEL & PLA/PLWCOMMAND COMPATIBILITY TABLE 135
APPENDIX B: PLW –COOLING SYSTEM GUIDELINE 139
APPENDIX C: PV SWEEP & PV OPERATION GUIDE 155

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TABLES AND FIGURES
TABLE 1.1a PLW GENERAL VOLTAGE AND CURRENT RANGES 12
TABLE 1.1b PLA GENERAL VOLTAGE AND CURRENT RANGES 13
FIGURE 1.1 LIQUID CRYSTAL DISPLAY 22
FIGURE 1.2 FRONT PANEL KEYPAD 23
TABLE 1.2 HOT KEY DESCRIPTION 23
TABLE 1.3 ENCODER OPERATION 24
FIGURE 1.5 INPUT VOLTAGE/CURRENT/POWER RELATION DIAGRAM 33
FIGURE 1.6 –PLW 2U FRONT PANEL 34
FIGURE 1.7 –PLW 2U REAR PANEL 35
FIGURE 1.8 –PLA 2U FRONT PANEL 36
FIGURE 1.9 –PLA 2U REAR PANEL 37
FIGURE 1.10–PLA 3U FRONT PANEL 38
FIGURE 1.11 –PLA 3U REAR PANEL 38
FIGURE 1.12–PLW 4U FRONT PANEL 40
FIGURE 1.13–PLW 4U REAR PANEL 40
FIGURE 1.14–PLA 4U FRONT PANEL 42
FIGURE 1.15–PLA 4U REAR PANEL 42
TABLE 2.1 BASIC SETUP PROCEDURE 44
FIGURE 2.1 SHIPPING OR STORAGE PACKAGE LABEL 46
TABLE 2.2 FUSE REPLACEMENT SPECIFICATIONS 47
TABLE 2.3 AC CORD SPECIFICATIONS 48
TABLE 2.4 CURRENT CARRYING WIRING CAPACITY FOR LOAD 48
FIGURE 2.2 PIPING AND COOLANT INSTALLATION 50
TABLE 2.5 VOLTAGE DROP COMPENSATION 52
FIGURE 2.3 LOCAL SENSE CONFIGURATION 53
FIGURE 2.4 REMOTE SENSE CONFIGURATION 54
FIGURE 2.5 PARALLEL CONFIGURATION 55
FIGURE 2.6 TRIGGER CONFIGURATION 56
FIGURE 2.7 ZERO-VOLT LOADING 56
TABLE 3.1 ENCODER OPERATION 60
FIGURE 3.2 EXTERNAL PROGRAMMING SETUP 64
TABLE 3.2 TRIGGER INPUT SOURCE 65
FIGURE 5.1 CALIBRATION SETUP CONFIGURATION SETUP 105

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ONE: FEATURES AND OPERATION OVERVIEW
INTRODUCTION
The PLA and PLW Series Programmable DC Electronic Load (eLoad) from AMREL offers a complete solution to the
electronic load system requirements. This instrument was designed to assist in the development and testing of new
products, as well as is being a standard instrument for automatic test systems and evaluation of dc power supplies,
batteries, and power components. Other applications include use as a power circuit breaker or crowbar, high current
function or pulse generator, fuel-cell and photovoltaic cell test, and de-energizing super conducting magnets. This
instrument uses advanced power MOSFETs to dissipate the input power. The electronic load consumes minimum power
to control maximum input power handling capability. Complex circuits are used to control the power balance and
dissipation of the MOSFET. This control circuit also supports the Constant Voltage (CV), Constant Current (CC),
Constant Resistance (CR), and Constant Power (CP) modes of operation. It comes with Standard Commands for
Programmable Instrument (SCPI) commands, remotemonitoring of input voltage and currents is a standard features. The
electronic load can be used either on your bench or in a standard 19 in. (483 mm) rack: occupies 3.5” - 8.75” (2U - 5 U)
of vertical rack space. Designed for continuous use in standalone or systems applications, this electronic load is typically
used to evaluateDC equipment,controlcircuits, or burn-in power applications.
TABLE 1.1a –PLW GENERAL VOLTAGE AND CURRENT RANGES
Note: √ = Max Voltage & Current Rated Model; Gray Highlight –Available Model Combinations

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PLW MODEL NUMBER DESCRIPTION
PLW 36K –400 –300 E
Model Type Power Rating Voltage Rating Current Rating E-Package Suffix
TABLE 1.1b –PLA GENERAL VOLTAGEAND CURRENTRANGES
Note: √ = Max Voltage & Current Rated Model; Gray Highlight –Available ModelCombinations
PLA MODEL NUMBER DESCRIPTION
PLA 5K –400 –300 E
Model Type Power Rating Voltage Rating Current Rating E-Package Suffix
FEATURES AND OPTIONS
•Four constant operating modes: Constant current (CC), constant voltage (CV), constant resistance (CR), and
constant current (CP) mode operation.
•Local control and remote programming for pulse amplitude,pulse width, and pulse cycle.
•Trig-In/Trig-Out and measurement functions.
•GPIB, RS-232, Ethernet,and USB interfaceprogramming with SCPI command language.
(Ethernet and USB are available as part of the E-Package).
•Front panelcontrol with keypad and rotary encoder(Tune Mode) for accuratesetting.

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•Built in pulse generator for continuous,pulsed, and toggled transient operation.
•Seven programmableprotection modes: Over Voltage Protection (OVP), Under Voltage Protection (UVP),
Over Current Protection (OCP), Under Current Protection (UCP), Overpower Protection (OPP), and Under
Power Protection (UPP).
•Fan speed control for reduced acousticnoise under light load conditions.
•0-10Vdc analogprogrammable.
•Simple closed-case calibration.
•Highest power density: up to 18KW in 2U height
•Field-upgradeable capability for GPIB, RS232, USB and Ethernet.
•Three ranges foreach operating mode; Auto or Manual
•External analogprogrammingcontrol for each mode and range
•Panel lock capability
•Program the Slew rise time and Slew falltime independently
•50us transient time at CC mode; 500ustransient time at CV mode
•Anti-Oscillation controls: System bandwidth controls
•Oscillation detection and protection
•Anti-Saturation controls: Under Voltage Lockout
•16 bits programming and read back capability
•Cross mode and Cross range capability; default off
•Remote Inhibit and Dry contact Fault output
•Pulse power capability with Overpower Protection
•Field-upgradeable firmware
•Self-diagnostic capability
•Redundant OverTemperature Protection
•Four Step profiles; 256 step points for each profile
•Soft-Start Functionality
•Convenient and efficient Hot Keys for mode and Transient Mode Selection, Input and Transient On/Off Control,
Slew Rate Settings, Front paneltrigger, and Short.
•Independent LargeNumerical Voltage and Current LED display
GENERAL INFORMATIONAND OPERATING NOTES
Operating Modes:
The four modesof operation are:
Constant Current (CC):
The electronic load will sink a current in accordancewith the programmed valueregardless of the input voltage.
Note 1: Never use CC mode for testing a constant current source. The regulation of the two units will fight forcontrol of
the current and an unstableoscillation will result.
Note 2: During CC mode,the electronic load can operate underthe fastest transient time.
Constant Voltage (CV):
The electronic load will attempt to sink enough current to control thesource voltage to theprogrammed value. It actsas a
shuntvoltage regulator when operatingin the CV mode.
Note 1: Never use CV modefor testing a constant voltagesource. The regulators of the two devices will buck each other
trying to gain controlof thevoltage which will lead toan unstablecondition.
Note 2: In CV mode,the transient time will be adjusted to a slower setting to ensure stable operation.

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Constant Resistance (CR):
The electronic load will sink a current linearly proportional to the input voltage in accordancewith the programmed
value.
Constant Power (CP):
The electronic load will dissipate the power in accordancewith the programmed value. It will automatically adjust the
current level inversely in response to a changein voltage.
Note: If thesource voltagedecaysto zero volts theload will attemptto draw max rated current. If theOCP limit of the
electronic load is greater than the current limit of the voltage source, the voltage source will be latched to the CC state.
Otherwise the OCP will trip to shut down the load.
Programming Mode Parameters:
When programmed to a mode,the electronic load remains in that mode until the mode is changed or until a fault
condition such asan overpower or over temperatureoccurrence. The current, voltage, resistance and power mode
parameterscan beprogrammed whetheror not the modeis presently activated. When a mode is selected via the front
panelor via the digital interfaces, the associated parameterswill then take effect at the instance of turning the input on.
Cross Mode:
According to AMREL eLoad design, the electronic load has fouroperating modes. As part of our factory default settings,
when switching from onemode to anothermode in manualrange(i.e. CV Low to CC High), the finalswitched statewill
have the input turned off. If an application requires the input to stay on when switching modes, the option “cross mode”
must be changed from “input off” to “input remain.” By changing the option, the load will switch between modes while
keeping the input on, to accommodate forthe different applicationsof the DUT.
Note: Cross mode operation will work under both “manual” and “auto” range control mode.
Ranges:
Parametersmay be programmed in any of the three overlapping ranges. The low range provides better resolution at low
settings. The range can be set using the front panelor via SCPI command. For auto-rangecontrol: when you program a
value, theelectronic load automaticallyselects the range that correspondsto thevalue youprogram. If the value falls in a
region where ranges overlap, the electronic load selects onewith thehighest resolution. In manual-rangecontrol: the
programmed valueswill be limited by the current range setting, an OUT OF RANGE message will appearon the front
paneldisplay when an invalid value is entered. When a range is selected, the associated parameters(preset value or value
from memory)will take into effect.
Cross Range Operation:
According to AMREL eLoad design specification, the electronic load hasthree overlapping operating ranges in each
mode. As partof our factory defaultsettings, when switching from one range to anotherrange in manualmode (i.e. CV
Low to CV High), the final switched state will have the input turned off. If an application requires the input to stay on
when switching ranges, the option “cross range” must be changed from “input off” to “input remain.” By changing the
option, theload will switch ranges while keeping the input on, to accommodateforthe different applicationsof the DUT.
The cross range featureallows the user to effectively switch between ranges based on the application needed by the DUT.
Note: Cross range operation will work under both “manual” and “auto” range control mode.
Immediate Level:
The immediate level can be set at front panelor via the digital interfaces. If the selected mode is active (Input on), the
new setting immediately changes the input at a rate determined by the soft-start turn-on sequence of the unit. If the
electronic load is not in theselected mode, thenew setting is saved until that particularmodeis activated.

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Transient Level:
The transient level can be set at front panelor via digital interfaces. The electronic load input will switch between the
mainlevel and thetransient level when transient operation is turned on. During transient operation,theload will switch
from the immediate level to thetransient level determined by theprogrammed slew time. When the load is in current
control mode,avoid the main level from zero. Because control circuits are potentially off.
TriggeredLevel:
The level can be preset (stored in the electronic load) allowing the input to be updated when a trigger is received. Trigger
level can only be changed via digital interfaces, and can be programmed to any value within the mode’s range settings.
Slew Rate:
The slew ratedetermines the rateat which the input to the electronic load changesto a new programmed value. Slew
time (positive and negative) and level change can be set at the front panel or via the digital interfaces. To better
accommodate userapplications,the positive and negative edge of the slew ratecan be set independently. The
programmed slew rate remains in effect forthe triggered and transient level changes previously described.
Input Control:
Short On/Off:
The electronic load can simulate a short circuit at its input by turning the load on with full-scale current. The short circuit
can be toggled on/off at the front panelor via the digital interfaceswhile Short On/Off is enabled. The short on/off
switch-over uses theslew rate setting of theactive modeand range. The actualvalue of the electronic short is dependent
on the mode and range that areactivewhen the short is turned on. In CV mode it is equivalent to programming zero
volts. In CC mode it is equivalent to programming full-scale current for the present current range. In CR mode it is
equivalent to programming theminimum resistance for the present resistance range.
Important Notes:
1) Turning the short on in CV modemay causetheload to draw so much current that thesoftware current limit
triggers, which may turn the input off (Protection Mode).
2) It is dangerous to activate short operation when testing batteries or other DUT without current limit. The
eLOAD will act as an infinite current sink, and drain Maximum Current until severe damagesoccurto both the
DUT and eLOAD. In the worst case scenario, the DUT/battery could catch on fire or explode.
Turning the short circuit on does not affect the programmed settings, and the load input will return to thepreviously
programmed valueswhen the short is turned off.
Input On/Off:
The electronic load’s input can be toggled on/off at the front panel,or via the digital interfaces. Turning the input off
(zero current) does not affect the programmed settings. The input will return to the previously programmed settings when
the input is activated again.
Note: The input on/off command supersedes the mode and short on/off command.
Transient Operation:
Transient operation enablesthe electronic load to periodically switch between two load levels. Transient operation can be
turned on and off at thefront panel or via the digital interfaces.Before you turn on the transient operation,you should set
the desired modeof operation as well as all of the parametersassociated with transient operation undervarying
combinations of load levels, frequency,duty cycle, and slew rate. Transient operation may be used in CC, CR, CV or CP
modesand can be continuous,pulsed, triggered, stepped or toggled. During transient operation,the load will switch from
the immediate level to the transient level determined by the programmed slew time. In cases where thetransition from

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one level to anotheris less than 5% of full rating, the smallsignal bandwidth of the load limits the minimum transition
time for all programmableslew rates.Because of this limitation, theactualtransition time is longer than the expected time
based on the slew rate.
Continuous Transient Operation
Generatea repetitive pulse train switches between two load levels via CONT (hot key) key or SCPI command.The two
load levels in the transient operation are main level and transient level for each mode.The rateat which the level switches
between is determined by the slew time setting.
Pulsed Transient Operation
Generatea load changethat returns to its original stateaftersome time period via SINGLE (hot key) key or SCPI
commands.
ToggledTransient Operation
Toggled transient operation causesthe electronic load input to alternate between two pre-defined load levels as in
Continuous Mode except that thetransient points can be controlled by explicit triggers instead of an internal transient
generator.
STEP Operation:
Step mode lets you generate complex sequencesof input changeswith rapid, precise timing, which may be synchronized
with internal or externalsignals.
You can program up to 256settings (or steps) in the profile, the time interval (dwell) that each setting is maintained,the
numberof times that thelist will be executed,and the setting’s changein response to thetriggers. The step data can be
stored in Profile 0, 1, 2 or 3 via either the front panelor the digital interfaces. Use RCL command to recall the saved state.
Trigger Operation:
The electronic load has various triggering modesto allow synchronization with other test equipment or events.
Triggeringa preset level
Transfers allpending preset levels to the actuallevel. For the presently activemode, the new level appearsat theinput.
For themodes which arenot presently active,the present levels will not takeeffect at theinput until the applicablemode
becomesactive. However, you must first initiate the trigger function by executingthe TRIG:IMMED command.
Triggeringa transient pulse
A trigger signal will generate a transient pulse of programmablewidth when pulsed transient operation is in effect.
Triggers can be sent from the front panel by pressing the TRIGGER key or via Remote Interface.
Toggling
A trigger signal will changethe input between the main level and the transient level when toggled transient operation is in
effect.Triggers can be sent from the front panel by pressing the TRIGGER key or via RemoteInterface.

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ProtectionFeatures:
The electronic load includes the following protection features:
Over Voltage (OV):
The eLOAD hasan Over Voltage Protection (OV) set at 105%of thefull voltage rating. If the input voltage exceeds
105% of the over voltage threshold, the input will shut off and an alarm message “OV” will display.
Over Current (OC):
The eLOAD hasan Over Current Protection (OC) set at 110%of the full current rating. If the input current exceeds
110% of the over current threshold, the input will shut off and an alarm message “OC” will display.
Overpower (OP):
The eLOAD has an Overpower Protection function set at 105% of rated power. If the power based on DC input terminals
voltage and current exceeds 105%of rated power, theunit will display warning message “OP” and theload will limit
input current level to maintain theinput power to prevent unit from over overload. Over temperatureprotection may trip
if the input power exceedsthe rated power persistently.
For eLOAD (with firmware version 2.86 or earlier), hasan Overpower Protection function set at 105%(PLW Models)
and 110% (PLA Models) of full Power Rating. If the accumulated energy based on operatingvoltage and current exceeds
the overpower threshold, the input will shut down and display the alarm message “OP”.
Over Temperature (OTP):
The electronic load has an over temperatureprotection circuit, which will turn off the input if the internal temperature
exceeds safe limits. Over-temperatureis usually the worse condition to happen to an electronic load due its highly
destructive effects. During high temperatureoperation(OTP condition), allinternal MOSFETS are working near their
full capacity andcan faildue to excessive heat. To prevent over temperature,theelectronic load hasa built in redundant
over temperatureprotection. In short, the OTP offers both a temperaturesensorcircuit that controlsthe internal cooling
system and a hardware thermalswitch that shuts down the input when the temperaturethreshold is exceeded.The
heatsink temperaturecan be display at front panelwith Meter Mode selection or Query via remotecommand.
Reverse Voltage (RCP):
The electronic load hasthe internal paralleldiodes to short the input in the presence of a reversed DC voltage input. The
front panel display with the alarm message “RCP” will indicate this condition hasbeen detected.
Remote Sense Fault (RSF):
If the connection to the sense leads is not proper when operating underremote sense mode,the input will be forced off
with the alarm message “RSF”; Remote Sense Fault. Two common errors that can result in “RSF” failure are while the
“Measure Sense” is set to remote, the sense leads are not connected or if the leads are connected and the connection is
lost. The latter can become a serious problem in CP mode. In Constant Power mode,the electronic load will maintain the
set wattageby balancingthevoltage and current. If the remote sense leads aredisconnected, the VMON of the load will
sense zero voltageand sink the amount of current needed to keep the same power level until OC or other protection are
triggered. The “RSF” protection will trigger if the voltagedeviation between the actualmeasured voltageand remote
sense voltage exceedsa set limit, forcing theinput off until theconditions is cleared.
Note: “RSF” error signal has precedence over OC with remote sense enabled,and will triggerif connectionislost.

M470039-01 REV-F Page 19
Unregulated state (UNR):
The “UNR” message cautions that the power stage of the electronic load is operating at its minimum resistance or
equivalent to it being shorted (marginal region forthe load). Another indication is that the load is being operated
improperly, i.e. not enough supply current/voltage or incorrect calibration data.
Supply Current and Voltage Below Main Level
A common causeforentering the unregulated state is supplying theload with a voltage or a current below the valueset
for electronic load’s main level. For example, if the input is off in CV mode and the main level of the load is set at 3 volts
and the power supply is programmed for2 volts. An “UNR” alarm message will appear when turning the input on. The
message is caused by the lack of voltageneeded to bring the main to 3 volts, and the voltage and current readings will be
unstable during this state. The same condition will occur forCC mode,if the needed current is lower than the supplied
current. To fix the problem, increase the voltage or current above the needed main value. The “UNR” threshold is set as
1% deviation from the maximum valuein that mode and/orrange.
Re-Calibration
Verify that the supply current and voltage is sufficient for the operating condition. If the “UNR” message still occurs,
check the current or voltageread back and compare it with the main value setting (CC mode: current; CV mode: voltage)
to make surethe difference is below 1%. If thedifference is above1%for CC/CV mode,30% forCR modeor 0.3% for
CP mode,that particularmode will need to be recalibrated. As a factory default,allloadsare calibrated to its optimal
condition. Please verify the calibration inaccuracy carefully or contact AMETEK Technical Support beforere-calibrating
the unit.
CR and CP Mode
In CR and CP mode,if thevoltage or current is below the needed value to reach a certain resistance or wattage,an
“UNR” alarm message will appear. For example,in order to obtain 300 watts, the input current value multiplied by the
input voltagevalue will need to equal300 watts, otherwise an error will occur. For CR mode, the input voltage value
divided by the input current value will need to equalthe resistance valueentered. To fix the problem, increase the voltage
or current above the needed power or resistance. The “UNR” threshold for constant power mode is set as 0.3% deviation
from the maximum value in that mode and/orrange. The constant resistance mode has a higher fluctuation in its value,so
it will have a higher “UNR” deviation range.
Note: When testing power supplies, a sudden current sink by the eLOAD in CP modemay cause the power supply to
latch in CC mode. At that time, the eLOAD will sink no current and display “UNR”. Simply power cycle the power
supply and repeat the application with a higher voltage setting to prevent the power supply from entering an
uncontrollablestate.
Precautions forTesting Batteries
As a precaution,when testing batteriesprevent from operatingin CV mode and make sure that the load does not enter the
unregulated state. If a battery is connected to a short circuited load (UNR state), the load will draw infinite current and
cause permanent damageto the load,battery undertest and possibly start a fire.
Under Voltage Lockout Protection (UVL):
The programmableundervoltage lockout featureallows the user to set a trip pointbetween zero and full-scale voltage (V-
On Voltage Threshold). The input will remain off until the input voltageis greater than thepre-programmed value or the
V-On Voltage threshold. For theV-On (UVL) feature,there are two modes that can be set. In “continuous”mode,the
UVL detection will remain active, and each time the voltage drops below the set threshold voltage, the UVL protection
will shut off theinput. Under “input on” mode, the UVL detection will only trigger once to shutdown the input and will
reset each time the input is cycled. The only way to clear a UVL protection messageis to increase the input voltage
beyond the V-On threshold. As a recommended setting, the V-On threshold should be set equivalent to at least 1 volt.