Tektronix 2450-EC Primary User
tek.com/keithley
Models 2450-EC, 2460-EC, and 2461-EC
Potentiostats and Galvanostats
User’s Manual
077110403 / March 2020
*P077110403*
077110403
Model 2450-EC, 2460-EC, and 2461-EC
Potentiostats and Galvanostats User's
Manual
© 2020, 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.
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Document number: 077110403 / March 2020
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
Table of contents
Introduction .......................................................................................................................... 1-1
Getting started ...................................................................................................................... 1-2
Power the instrument on or off .................................................................................................. 1-3
Select the high-impedance, output-off state .............................................................................. 1-4
Copy a script to the instrument .................................................................................................. 1-5
Cable assembly details ........................................................................................................ 1-7
Connections and usage ....................................................................................................... 1-7
Make the SMU connections ...................................................................................................... 1-8
Make the device connections .................................................................................................... 1-9
Attach the alligator clips .......................................................................................................... 1-10
Prepare the analyte and assemble the test cell....................................................................... 1-10
Connect to the DUT ................................................................................................................ 1-10
Home and Menu screen overview ........................................................................................... 1-11
Cyclic voltammetry ................................................................................................ .. 2-1
Cyclic voltammetry ............................................................................................................... 2-1
Test application parameters ...................................................................................................... 2-2
Run the cyclic voltammetry test application............................................................................... 2-3
Review the menu controls ......................................................................................................... 2-4
Define the potential scan parameters ........................................................................................ 2-5
Define the scan settings ............................................................................................................ 2-7
Modify the measure settings ..................................................................................................... 2-8
Save or load the test parameter data ...................................................................................... 2-11
Run the test and view the graph .............................................................................................. 2-13
Acquire the open-circuit potential (Eoc) .................................................................................. 2-14
Save the test data to the flash drive ........................................................................................ 2-15
View the results saved to the flash drive ................................................................................. 2-15
View the test reading table ...................................................................................................... 2-16
View the event log ................................................................................................................... 2-16
End the test application ........................................................................................................... 2-17
Cyclic voltammetry theory ....................................................................................................... 2-17
Open-circuit potential .............................................................................................. 3-1
Open-circuit potential ........................................................................................................... 3-1
Test application parameters ...................................................................................................... 3-2
Run the open-circuit potential test application ........................................................................... 3-2
Review the menu controls ......................................................................................................... 3-4
Adjust the measure settings ...................................................................................................... 3-4
Save or load the test parameter data ........................................................................................ 3-6
Run the test and view the graph ................................................................................................ 3-8
Save the test data to the flash drive .......................................................................................... 3-9
View the results saved to the flash drive ................................................................................... 3-9
View the reading table or measurement statistics ................................................................... 3-10
View the event log ................................................................................................................... 3-10
End the test application ........................................................................................................... 3-11
Potential pulse and square wave ............................................................................ 4-1
Potential Pulse and Square Wave ....................................................................................... 4-1
Test application parameters ...................................................................................................... 4-2
Table of contents 2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual
Run the potential pulse and square wave test application ........................................................ 4-3
Review the menu controls ......................................................................................................... 4-4
Configure the pulse settings ...................................................................................................... 4-5
Adjust the end conditions .......................................................................................................... 4-8
Save or load the test parameter data ...................................................................................... 4-10
Run the test and view the graph .............................................................................................. 4-11
Save the test data to the flash drive ........................................................................................ 4-12
View the results saved to the flash drive ................................................................................. 4-13
View the reading table or measurement statistics ................................................................... 4-13
View the event log ................................................................................................................... 4-14
End the test application ........................................................................................................... 4-14
Current pulse and square wave .............................................................................. 5-1
Current pulse and square wave ........................................................................................... 5-1
Test application parameters ...................................................................................................... 5-2
Run the current pulse and square wave test application ........................................................... 5-3
Review the menu controls ......................................................................................................... 5-4
Configure the pulse settings ...................................................................................................... 5-5
Adjust the end conditions .......................................................................................................... 5-8
Save or load the test parameter data ...................................................................................... 5-10
Run the test and view the graph .............................................................................................. 5-11
Save the test data to the flash drive ........................................................................................ 5-12
View the results saved to the flash drive ................................................................................. 5-13
View the reading table or measurement statistics ................................................................... 5-13
View the event log ................................................................................................................... 5-14
End the test application ........................................................................................................... 5-14
Chronoamperometry ................................................................................................ 6-1
Chronoamperometry ............................................................................................................ 6-1
Test application parameters ...................................................................................................... 6-2
Run the chronoamperometry test application ............................................................................ 6-3
Review the menu controls ......................................................................................................... 6-4
Configure the step and measure settings .................................................................................. 6-4
Save or load the test parameter data ........................................................................................ 6-8
Run the test and view the graph ................................................................................................ 6-9
Save the test data to the flash drive ........................................................................................ 6-10
View the results saved to the flash drive ................................................................................. 6-11
View the reading table or measurement statistics ................................................................... 6-11
View the event log ................................................................................................................... 6-12
End the test application ........................................................................................................... 6-12
Chronopotentiometry............................................................................................... 7-1
Chronopotentiometry ............................................................................................................ 7-1
Test application parameters ...................................................................................................... 7-2
Run the chronopotentiometry test application ........................................................................... 7-3
Review the menu controls ......................................................................................................... 7-4
Configure the step and measure settings .................................................................................. 7-4
Save or load the test parameter data ........................................................................................ 7-8
Run the test and view the graph ................................................................................................ 7-9
Save the test data to the flash drive ........................................................................................ 7-10
View the results saved to the flash drive ................................................................................. 7-11
View the reading table or measurement statistics ................................................................... 7-11
View the event log ................................................................................................................... 7-12
End the test application ........................................................................................................... 7-12
In this section:
Introduction .............................................................................. 1-1
Getting started .......................................................................... 1-2
Cable assembly details ............................................................ 1-7
Connections and usage ........................................................... 1-7
Introduction
Section 1
Introduction
The Keithley Instruments Models 2450-EC, 2460-EC, and 2461-EC Potentiostat/Galvanostat systems
are alternatives to traditional electrochemistry potentiostats and galvanostats. Your instrument
features a full-color, high-resolution touchscreen, which lets you configure tests and immediately view
results.
The following electrochemistry test applications are loaded in the memory of your instrument:
• Cyclic voltammetry: Potential is swept at a user-programmable scan rate between two to four
defined potential vertices, and the resulting current is measured at specified intervals during the
sweep.
• Open-circuit potential: Measures the cell potential difference between two electrodes with high
input impedance as a function of time.
• Potential pulse and square wave with current measure: Sources potential at programmable
peak and base levels. The resulting current at the pulse peak level is recorded.
• Current pulse and square wave with potential measure: Sources current at programmable
peak and base levels. The resulting potential at the pulse peak level is recorded.
• Chronoamperometry: Potential is stepped to a programmed value and the resulting current is
measured as a function of time.
• Chronopotentiometry: Current is stepped to a programmed value and the resulting potential is
measured as a function of time.
Section 1: Introduction 2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual
1-2 077110403 / March 2020
This kit is not intended to be used with a SMU interlock enabled. To prevent electric shock
and possible damage to the test cable assembly or test setup, do not activate the Keithley
Instruments 2450, 2460, or 2461 interlock.
When the interlock is not engaged on the 2450, 2460, or 2461 the nominal output is limited to
±42 V. However, review the "Safety Precautions" section of this document to ensure
responsible operation.
Getting started
In addition to your SourceMeterTM instrument, you should have received the following items:
• One electrochemistry interface cable that connects the instrument to a 2-, 3-, or 4-terminal
electrochemical cell
• Four insulated miniature alligator clips
• One flash drive that contains the test applications and supporting documentation.
• Six electrochemistry test applications
Before you can run an electrochemistry test, you will need to configure the instrument and make basic
connections. The following topics will explain how to set up and configure your instrument.
The 2450-EC or 2460-EC instrument must have firmware version 1.5.0 or later to run the
electrochemistry test applications. The 2461-EC must have firmware version 1.6.0 or later.
Scripts with version numbers lower than 189427 are compatible with firmware versions 1.5.0 (1.6.0
for 2461) to 1.6.7. Scripts with version numbers of 189427 and higher are compatible with
firmware versions 1.5.0 (1.6.0 for 2461) to 1.6.7 and version 1.7.2 and higher. The script version
number is displayed near the top right corner of an application's Home screen.
To view the firmware version, press the MENU key, then select Info/Manage under System. The
firmware version is at the upper-left of your display. The latest firmware is available from the
Keithley Instruments website (tek.com/keithley).
2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual Section 1: Introduction
077110403 / March 2020 1-3
The following files are loaded onto the flash drive:
File
Description
CyclicVoltammetry.tsp
Application to perform cyclic voltammetry
OpenCircuitPotential.tsp
Application to measure the open-circuit potential
Chronoamperometry.tsp
Application to measure the current as a function of time at
a constant potential
Chronopotentiometry.tsp
Application to measure the potential as a function of time
at a constant current
CurrentPulseAndSquareWave.tsp
Application to output a current pulse or square wave while
measuring the potential
PotentialPulseAndSquareWave.tsp
Application to output a current pulse or square wave while
measuring the current
EC_Images.tsp
Potentiostat application images
EC_Framework.tsp
Potentiostat application framework
07711040x_2450-EC.pdf
Models 2450-EC, 2460-EC, and 2461-EC Potentiostats
User's Manual (this document)
07134730x_ECHEM-KIT.pdf
SMU Potentiostats and EC-UPGRADE Kit Quick Start
Guide
Power the instrument on or off
Follow the steps below to connect the 24xx-EC to line power and turn on the instrument. The
24xx-EC operates from a line voltage of 100 V to 240 V at a frequency of 50 Hz or 60 Hz. It
automatically senses line voltage and frequency. Make sure the operating voltage in your area is
compatible.
You must turn on the 24xx-EC and allow it to warm up for at least one hour to achieve rated
accuracies.
Operating the instrument on an incorrect line voltage may cause damage to the instrument,
possibly voiding the warranty.
The power cord supplied with the 2450-EC, 2460-EC, and 2461-EC contains a separate
protective earth (safety ground) wire for use with grounded outlets. When proper connections
are made, the instrument chassis is connected to power-line ground through the ground wire
in the power cord. In addition, a redundant protective earth connection is provided through a
screw on the rear panel. This terminal should be connected to a known protective earth. In
the event of a failure, not using a properly grounded protective earth and grounded outlet
may result in personal injury or death due to electric shock.
Do not replace detachable mains supply cords with inadequately rated cords. Failure to use
properly rated cords may result in personal injury or death due to electric shock.
Section 1: Introduction 2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual
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To connect the power cord:
1. Make sure that the front-panel POWER switch is in the off (O) position.
2. Connect the female end of the supplied power cord to the AC receptacle on the rear panel.
3. Connect the male end of the power cord to a grounded AC outlet.
To turn the instrument on or off:
1. Before turning the instrument on, disconnect any devices under test (DUTs) from the instrument.
2. To turn your instrument on, press the front-panel POWER switch to place it in the on (|) position.
The instrument displays a status bar as it powers on. The home screen is displayed when power
on is complete.
3. To turn your instrument off, press the front-panel POWER switch to place it in the off (O) position.
On some sensitive or easily damaged devices under test (DUTs), the instrument power-up and
power-down sequence can apply transient signals to the DUT that may affect or damage it. When
testing this type of DUT, do not make final connections to it until the instrument has completed its
power-up sequence and is in a known operating state. When testing this type of DUT, disconnect it
from the instrument before turning the instrument off.
To prevent any human contact with a live conductor, connections to the DUT must be fully insulated
and the final connections to the DUT must only use safety-rated safety jack socket connectors that do
not allow bodily contact.
Select the high-impedance, output-off state
Before making physical connections from the instrument to the test cell, set the output of the
instrument to the high-impedance, output-off state. When the high-impedance output-off state is
selected, the output relay opens, disconnecting the instrument from the load.
To set the output of your SMU to the high-impedance output-off state:
1. Press the MENU key.
2. Under Source, select Settings.
3. Select Output Off.
4. Choose High Z (high impedance).
You may receive a notification about making measurements with the output turned off. Select OK to
clear the message or select Details to see more information.
2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual Section 1: Introduction
077110403 / March 2020 1-5
Copy a script to the instrument
Your SMU is shipped with all test applications and supporting scripts loaded into memory.
If you accidentally delete a test application or a supporting script (EC_Framework.tsp or
EC_Images.tsp), you can copy the files from the flash drive to your instrument.
If you are upgrading your SMU with the EC-UPGRADE kit, you can run the test applications from the
flash drive or copy the files from the flash drive to the instrument. If you choose to copy the
applications, you must also copy the support files (EC_Framework.tsp and EC_Images.tsp) to
your SMU.
To copy a script to the SMU:
1. Insert the USB flash drive into the USB port on the front panel.
2. Press the MENU key.
3. Under Scripts, select Manage. The Manage Scripts menu opens. Your list of Internal Scripts may
appear different than the following figure.
Figure 1: Manage Scripts menu
Section 1: Introduction 2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual
1-6 077110403 / March 2020
4. In the USB Scripts list, select the test script you want to copy to the SMU. For this example, you
will copy the cyclic voltammetry test script.
Figure 2: Selecting the test script to be copied
5. Select <. The test script is transferred to the instrument, and the corresponding filename is
displayed in the Internal Scripts list.
Figure 3: Copying the file to the instrument
2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual Section 1: Introduction
077110403 / March 2020 1-7
Cable assembly details
Maximum voltage (assembly):
42 V
Maximum current (assembly):
7 A on HI and LO, less than 1 mA on SHI and SLO
The cable is an electrically-shielded 1 m (39.37 in.) assembly with stackable, safety banana plugs on
both ends. This cable simplifies the connections between your SMU potentiostat or galvanostat and
an electrochemical test cell.
Figure 4: ECHEM accessory cable dimensions
Electrical characteristics
Connections and usage
The cable assembly can be used with Keithley SMUs for electrochemistry applications. Each
connector of the assembly is labeled according to its function:
Figure 5: Cable assembly connector labels and definitions
Section 1: Introduction 2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual
1-8 077110403 / March 2020
Make the SMU connections
To connect to the instrument (all tests):
The front panel of your SMU has four banana-style input and output jacks. You use the supplied
cable to connect your electrochemical cell to these jacks.
The SENSE terminals are used to measure voltage at the device under test (DUT). When you use
sense leads, the voltage drop across the force leads is eliminated from a measurement. This
produces more accurate voltage sourcing and measurement at the DUT. Plug the SHI and SLO
connectors into the SENSE terminals.
The FORCE terminals are used to source or sink voltage or current to or from a DUT. Plug the HI and
LO connectors into the FORCE terminals.
Plug the four SMU-side cable connectors into the front of your SMU instrument as shown in the below
graphic.
Figure 6: Connecting SMU-side cable connectors to the SMU front-panel inputs
2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual Section 1: Introduction
077110403 / March 2020 1-9
Make the device connections
The test cable lets you make connections to test cells with two, three, or four electrodes.
For two-electrode applications, the device-side cable connectors are used in stacked pairs. Connect
the WE and WES pair to the working electrode of your electrochemical cell, and connect the CE and
RE pair to the counter electrode of the cell.
Figure 7: Two-electrode cell testing cable connections
For three-electrode applications, the WE and WES connectors are stacked and attached to the
working electrode. The CE and RE connectors connect to the counter electrode and reference
electrode, respectively.
Figure 8: Three-electrode cell testing cable connections
For four-electrode applications, each device-side cable connector is used separately.
Figure 9: Four-electrode cell testing cable connections
Section 1: Introduction 2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual
1-10 077110403 / March 2020
Attach the alligator clips
Four insulated alligator clips are supplied. You can attach these clips to the ends of the device-side
connectors, as shown in the following graphic. The clips provide a safe, secure way to connect to
your device.
Figure 10: Alligator clip attached to accessory cable connector
For small cells and electrodes, you can use commercially available banana-to-microclip connectors
by plugging them directly into the cable connectors.
Once the appropriate connectors or clips are attached, you are ready to connect to the test cell.
Prepare the analyte and assemble the test cell
Before connecting to the DUT, make sure to prepare the analyte and assemble the test cell for your
test.
Connect to the DUT
The next figure shows the connections from a SMU to a three-electrode test cell.
Figure 11: Front panel connections
2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual Section 1: Introduction
077110403 / March 2020 1-11
Home and Menu screen overview
Before you run a test application, the default Home and Menu screens of your SourceMeter
instrument appear like those in the next graphic. Press the HOME or MENU keys on your instrument
to access these screens.
Figure 12: SMU Home and Menu screens in standard mode
When you run an electrochemistry test application, the default Home and Menu screens are replaced
by application-specific Home and Menu screens. These screens vary, depending on the potentiostat
or galvanostat test application. You can access these screens with the HOME and MENU keys. You
will see examples of these screens later in this manual.
When a test application is running, you must select End App to exit the test and return to normal
SMU operation.
For more information on using your SMU, see your Interactive SourceMeter® Instrument Reference
Manual.
In this section:
Cyclic voltammetry ................................................................... 2-1
Section 2
Cyclic voltammetry
Cyclic voltammetry
Cyclic voltammetry, a type of potential sweep method, is the most commonly-used measurement
electrochemical technique.
In a cyclic voltammetry experiment, the working electrode potential is ramped linearly versus time.
The current that flows through the circuit is measured. The resulting I-V data provides important
electrochemical properties about the analyte under investigation.
You can make cyclic voltammetry measurements from the front panel of the instrument using the
cyclic voltammetry test application.
The cyclic voltammetry test application has adjustable parameter settings and enables real-time
graphing of a voltammogram on the display of the SMU potentiostat without using a computer. Test
parameters are input at source and measure setting screens that the user selects from an
application-specific menu. After the test executes, the data can be stored on a flash drive inserted in
the USB port on the front panel of the instrument.
The following topics describe how to set up and run the CyclicVoltammetry.tsp test application.
To ensure proper instrument operation, the potential difference between the reference electrode (RE)
and counter electrode (CE) terminals and between the working electrode (WE) and working
electrode sense (WES) terminals should not exceed 5 V.
Section 2: Cyclic voltammetry 2450-EC, 2460-EC, and 2461-EC Potentiostats and Galvanostats User's Manual
2-2 077110403 / March 2020
Test application parameters
You must enter test parameters that are consistent with the following values. Otherwise, you
may receive unsettled and inaccurate measurements.
The cyclic voltammetry test application parameters are listed below.
Model 2450-EC
• Potential range: – 20 V ≤ E ≤ +20 V
• Current measure ranges: 10 μA, 100 μA, 1 mA, 10 mA, 100 mA, 1 A
• Source limit (compliance): 100% of selected current range
• Scan rate: 0.1 mV per second to 3500 mV per second
• Potential step size during scanning:
▪ 100 μV (0.1 mV per second ≤ scan rate < 35 mV per second)
▪ 1 mV (35 mV per second ≤ scan rate < 350 mV per second )
▪ 10 mV (350 mV per second ≤ scan rate ≤ 3500 mV per second)
• Number of cycles: 1 to 100
• User-selectable sampling intervals:
▪ Points per test (10 to 10,000)
▪ Points per cycle (10 to 10,000)
▪ Seconds per point (0.01 to 100)
▪ Points per second (0.01 to 100)
• Maximum total number of samples: 100,000
• High-capacitance mode
Models 2460-EC and 2461-EC
• Potential range: –20 V ≤ E ≤ +20 V
• Current measure ranges: 1 mA, 10 mA, 100 mA, 1 A, 4 A, 5 A, 7 A
• Source limit (compliance): 100% of selected current range
• Scan rate: 0.1 mV per second to 3500 mV per second
• Potential step size during scanning:
▪ 100 μV (0.1 mV per second ≤ scan rate < 35 mV per second)
▪ 1 mV (35 mV per second ≤ scan rate < 350 mV per second )
▪ 10 mV (350 mV per second ≤ scan rate ≤ 3500 mV per second)
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• Number of cycles: 1 to 100
• User-selectable sampling intervals:
▪ Points per test (10 to 10000)
▪ Points per cycle (10 to 10000)
▪ Seconds per point (0.01 to 100)
▪ Points per second (0.01 to 100)
• Maximum total number of samples: 100,000
• High-capacitance mode
Run the cyclic voltammetry test application
To run the test application:
1. Press the HOME key.
2. Select the active script indicator at the top of your home screen. If there is no script activity, the
indicator displays No Script.
Figure 13: Active script indicator
3. Select the preloaded cyclic voltammetry test script (potentiostats and galvanostats only) or
connect the supplied USB drive to your SMU instrument to locate the included cyclic voltammetry
test. If you connect the USB drive, scripts on the drive are displayed with usb1/ before the script
file name.
Figure 14: Selecting the cyclic voltammetry test application
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4. Select CyclicVoltammetry. The test application begins to run immediately and the cyclic
End App
Select this control to immediately stop the test and return to normal SMU
operation.
Autoscale
Select this control to define the graph based upon the plotted data. This is
useful for constraining all of the data to the screen's viewing size.
Start Test
Select this control to immediately begin the test. This option becomes Stop
Test when the test runs.
Save Data
Select this control to save the test data to a .csv file on a flash drive. This
option is only visible after the test runs.
Cursor
Select this control to cycle through the available cursor placements: None,
Vertical, Horizontal, and Both.
voltammetry home screen is displayed.
Figure 15: Cyclic voltammetry home screen
The test home screen controls include:
Review the menu controls
You have different options in the Menu screen, depending on the application. The following graphic
shows the cyclic voltammetry main Menu. You will learn the function for each option later in this
section.
Figure 16: Cyclic voltammetry main Menu
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Define the potential scan parameters
You will define the potential scan parameters: Number of vertices, vertex potentials, potential
reference, scan rate, and number of cycles.
An example of a potential scan performed during a cyclic voltammetry test is shown in the next figure.
You can select up to four voltage potential vertices, which are defined as E1 (or E initial), E2, E3, and
E4 in the next figure. The slope of the lines is determined by the scan rate that you use. You will set
the scan rate later in this step of the test.
Figure 17: Potential sweep versus time of cyclic voltammetry example
For this step, you will set the Number of vertices, define their potentials, and specify the potential
reference.
To select the Number of Vertices:
1. Press the MENU key, then select Scan Settings.
2. Select Number of Vertices.
Figure 18: Scan Settings menu
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3. Enter the number of potential vertices. You can define two, three, or four vertices.
4. The vertex selections will change based on the number of vertices you choose. Select each
vertex to enter its potential. For this example, you will define four vertices.
Figure 19: Scan Settings menu, defining four vertices
5. Enter each vertex value in the range of ±20 V.
After you define the vertices, select the potential reference: Eref or Eoc. If you select Eref, the applied
potential is relative to the potential at the reference electrode. If you select Eoc, the applied potential
is relative to the open-circuit potential of the cell (Eoc), which is measured immediately before the
scan begins.
To select the potential reference:
1. From the Scan Settings menu, select Reference.
Figure 20: Scan Settings menu, selecting Reference
2. Select Eref or Eoc.
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Define the scan settings
You can specify the scan rate in units of millivolts per second. The scan rate, defined as the change
of the potential as a function of time (∆E/∆t), determines the rate at which the potential is linearly
scanned during the experiment. You can select a scan rate of 0.1 mV per second to 3500 mV per
second.
To select the scan rate:
1. From the scan Settings menu, select Scan Rate
Figure 21: Scan Settings menu, selecting Scan Rate
2. Enter a value.
3. Select OK.
After entering the scan rate, you will choose the number of cycles, from 1 to 100. The number of
cycles determines how many times each scan is repeated.
To select the number of scan cycles:
1. From the Scan Settings screen, select Number of Cycles.
Figure 22: Scan Settings menu, selecting the Number of Cycles
2. Enter a value.
3. Select OK.
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The following figure shows an example of a potential versus time graph showing three cycles of a
Sampling rate unit
Description
Sampling rate range of values
points/test
The number of points acquired during a test,
regardless of how many cycles
10 to 10,000
points/cycle
The number of points acquired in each cycle
10 to 10,000
s/point
The number of seconds per each point
0.01 to 100
points/s
The number of points taken per second
0.01 to 100
three-vertex voltage sweep.
Figure 23: Example potential versus time graph
Modify the measure settings
Specify how often to make measurements during the scan by selecting one of the sampling rate units
shown in the following table and setting a value for the sampling rate. The acquired measurements
are stored in the active buffer of the instrument, cvBuffer. The buffer can hold a maximum of
100,000 readings.
The following table describes the available interval units and accompanying range of values.
To select the sampling rate units:
1. From the Menu screen, select Measure Settings.
2. Select Sampling Rate Units.
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Figure 24: Measure Settings menu, selecting Sampling Rate Units
3. Select the units you want to use for the test. You can now set a sampling rate.
To set the sampling rate:
1. From the Measure Settings screen, select Sampling Rate.
2. Enter a value.
3. Select OK.
Now you will select the current range to measure the current from the scan. Choose the range based
upon the largest current magnitude you expect during the test.
To select the current measurement range:
1. From the Measure Settings screen, select Current Range.
Figure 25: Measure Settings menu, selecting Current Range
When the test runs, your potentiostat will limit the magnitude of the maximum current that can flow in
the test circuit to 100 percent of the selected current range. This could affect your experiment results.
If your expected current is near the full scale of a range, select the next highest current range to
minimize the influence of your potentiostat on the test.
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2. Choose a value. Note that the choices are different depending on your potentiostat model.
Figure 26: Selecting the current range
Although rare, you may encounter overshoot, ringing, or other instability on the output of your SMU
potentiostat depending the electrical impedance of your chemical cell. This is particularly an issue
when the impedance is capacitive and you are forcing voltage and measuring relatively low currents,
as with the cyclic voltammetry test.
In these cases, you can use the high-capacitance mode to minimize overshoot, ringing, and instability.
See your 24XX Interactive SourceMeterTM Reference Manual for more information.
To select the high-capacitance mode:
1. From the Menu screen, select Measure Settings.
2. Select High Capacitance.
Figure 27: High Capacitance Mode selection
3. Select Off or On.
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Save or load the test parameter data
You can save your test parameters to the front-panel flash drive at any time. Up to five test parameter
configurations can be stored.
To save the test parameters:
1. From the Menu screen, select Save Settings.
If you have saved a settings file previously with the same File Selection number, you will be
prompted to overwrite it.
Figure 28: Selecting Save Settings
2. Select a file number and then select Save Settings. You are notified when the save is complete,
as shown in the next figure. Select OK to clear the prompt.
Figure 29: Successful file save
To load saved test parameters:
Test parameters can only be loaded to the same instrument model on which they were created and
saved. For example, you cannot load test parameter settings created with a 2450-EC to a 2460-EC.
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1. From the Menu screen, select Load Settings.
Figure 30: Selecting Load Settings
2. Select a file by choosing File Selection and then a file number.
Figure 31: Choosing a file to load
3. Select Load Settings. You are notified when the load completes. Select OK to clear the prompt.
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