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Technique Command
Use this command to select an electrochemical technique.
This command presents an Electrochemical Techniques dialog box:
The following options allow you to select an electrochemical technique:Technique Selection
Select the electrochemical technique you want to use. This box lists the techniques
available in the instrument. Double clicking the technique you want to select is equivalent toselecting the technique and clicking the OK button.Polarographic Mode
Check this box will enable the polarographic mode. In the polarographic mode, themercury drop will be allowed to grow and be dislodged for every data point.
Only a few techniques are allowed to have polarographic mode: Sampling Current(Staircase) Polarography (SCP), Differential Pulse Polarography (DPP), Normal Pulse
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Chapter 4. Setup Menu
________________________________________________________________________Polarography (NPP), Differential Normal Pulse Polarography (DNPP), A.C. Polarography(ACP), and Second Harmonic A.C. Polarography (SHACP).
Once polarographic mode is enabled, stripping mode is disabled. In order to set strippingmode by using the Stripping Mode command in Control Menu, you have to uncheck thepolarographic mode.
This command has a toolbar button:
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Chapter 4. Setup Menu
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Parameters Command
Use this command to set experimental parameters.
This command presents a Parameter dialog box so you can select the parameters youwant to use.
Depending on the technique, the parameters dialog box will be different. The followingsare the parameters for different techniques:
Parameters for Cyclic Voltammetry
Parameters for Linear Sweep VoltammetryParameters for Sampled Current VoltammetryParameters for Tafel Plot
Parameters for ChronoamperometryParameters for Chronocoulometry
Parameters for Differential Pulse VoltammetryParameters for Normal Pulse Voltammetry
Parameters for Differential Normal Pulse VoltammetryParameters for Square Wave VoltammetryParameters for A.C. Voltammetry
Parameters for 2nd Harmonic A.C. VoltammetryParameters for Amperometric i-t Curve
Parameters for Differential Pulse Amperometry
Parameters for Double Differential Pulse AmperometryParameters for Triple Pulse Amperometry
Parameters for Integrated Pulse Amperometric DetectionParameters for Bulk Electrolysis with Coulomtery
Parameters for Hydrodynamic Modulation VoltammetryParameters for Sweep-Step FunctionsParameters for Multi-Potential StepsParameters for A.C. ImpedanceParameters for Impedance - TimeParameters for Impedance - PotentialParameters for Chronopotentiometry
Parameters for Chronopotentiometry with Current RampParameters for Multi-Current Steps
Parameters for Potentiometric Stripping AnalysisParameters for Open Circuit Potential - Time
For details of the parameters of each technique, see the description of individual dialogbox of related techniques.
This command has a toolbar button:
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Chapter 4. Setup Menu
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Parameters for Cyclic Voltammetry
In Cyclic Voltammetry (CV), potential is scanned from Init E toward either High E orLow E depending on the Init P/N. The potential will then scan back. The following diagramshows the potential waveform applied as the function of time. The current is recorded as thefunction of potential.
High E
Potential(V)Scan Rate (V/s)
Init E
Low E
Segment 1
Segment 2
Segment 3
Time (s)
The following are the experimental parameters, their range and descriptions:
ParametersInit E (V)High E (V)Low E (V)Init P/N
Scan Rate (V/s)Sweep SegmentsSample Interval (V)Quiet Time (sec)Sensitivity (A/V)Auto Sens
Scan Complete CyclesAuxiliary SignalRecording
Notes:
Range-10 - +10-10 - +10-10 - +10
Positive or Negative1e-6 - 200001 - 10000001e-6 - 0.0640 - 1000001e-12 - 0.1
Check or UncheckCheck or UncheckCheck or Uncheck
DescriptionInitial potential
High limit of potential scanLow limit of potential scanInitial scan directionPotential scan rate
Sweep segments, each segments is half cycleData sampling interval
Quiescent time before potential scanSensitivity scale
Automatic sensitivity switching during runScan complete cycles
Simultaneously external signal recordingwhen the scan rate is less than 0.25V/s
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Chapter 4. Setup Menu
________________________________________________________________________1.High E and Low E should be at least 0.01 V apart.
2.If unreasonable High E and Low E are entered, the system will automatically readjustthem.
3.Depending on the Init E, High E and Low E value, the system will automatically readjustinitial scan direction.
4.The maximum potential scan range is 13.1V.
5.The potential increment is 0.1 mV if the scan rate is below 500 V/s. The potentialincrement is 1 mV at the scan rate of 5000 V/s, and 4 mV at 20000 V/s.
6.The sample interval can be 1 mV When the scan rate is below 1000 V/s. The sampleinterval is 2 mV at the scan rate of 2000 V/s, 5 mV at 5000 V/s, and 20 mV at 20000 V/s. Ifthe scan rate is high, the data sampling interval will be automatically increased.
7.When large number of sweep segments are involved, the data sampling interval will beautomatically increased up to 0.02V. If the scan rate is higher than 0.5V/s, the number ofsweep segments will be limited by the memory size (64000 points). If the scan rate is below0.5V/s, the maximum data length set by the System command will take effect. When the scanrate is low, the specified sweep segments will be executed, but only limited number ofsegments will be stored. Large sweep segments might be useful for conditioning ofelectrodes.
8.When scan rate is below 0.01 V/s, the sensitivity scale during run can be automaticallyswitched according to the current level. When it is activated, the sensitivity selection willhave no effect on the measurement. However, the automatic sensitivity switching range willbe from 1e-8 - 0.1 A/V, instead of 1e-12 - 0.1 A/V. The Picoamp Booster will not workeither. In order to select higher sensitivities, automatic sensitivity switching option needs tobe disabled.
9.Scan Complete Cycles will only work for Sweep Segments at 3, 5, 7, 9, (odd numbers)and if Initial E is different from High E and Low E. When it works, the last segment will stopat Initial E instead of High E or Low E.
10.If the scan rate is lower than 0.25V/s, it is possible to record external voltage signal (suchs spectroscopic signal) simultaneously with the voltammogram. Use the 9-pin D-connectoron the real panel for signal input. Check the User's Manual for the pin-out and signal levelrequirements.
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Chapter 4. Setup Menu
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Parameters for Linear Sweep Voltammetry
In Linear Sweep Voltammetry (LSV), potential is scanned from Init E toward Final E.The following diagram shows the potential waveform applied as the function of time. Thecurrent is recorded as the function of potential.
Final E
Potential(V)Scan Rate (V/s)
Init E
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Scan Rate (V/s)Sample Interval (V)Quiet Time (sec)Sensitivity (A/V)Auto SensAuxiliary SignalRecording
Range-10 - +10-10 - +101e-6 - 200001e-6 - 0.0640 - 1000001e-12 - 0.1Check orUncheckCheck orUncheck
DescriptionInitial potentialFinal potentialPotential scan rateData sampling interval
Quiescent time before potential scanSensitivity scale
Automatic sensitivity switchingduring run
Simultaneously external signalrecording when the scan rate is lessthan 0. 25V/s
Notes:
1.Init E and Final E should be at least 0.01 V apart.2.The maximum potential scan range is 13.1 V.
3.When the scan rate is high, the data sampling interval will be automatically increased.
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________________________________________________________________________4.The potential increment is 0.1 mV if the scan rate is below 500 V/s. The potentialincrement is 1 mV at the scan rate of 5000 V/s, and 4 mV at 20000 V/s.
5.The sample interval can be 1 mV When the scan rate is below 1000 V/s. The sampleinterval is 2 mV at the scan rate of 2000 V/s, 5 mV at 5000 V/s, and 20 mV at 20000 V/s. Ifthe scan rate is high, the data sampling interval will be automatically increased.
6.When scan rate is below 0.01 V/s, the sensitivity scale during run can be automaticallyswitched according to the current level. When it is activated, the sensitivity selection willhave no effect on the measurement. However, the automatic sensitivity switching range willbe from 1e-8 - 0.1 A/V, instead of 1e-12 - 0.1 A/V. The Picoamp Booster will not workeither. In order to select higher sensitivities, automatic sensitivity switching option needs tobe disabled.
7.If the scan rate is lower than 0.25V/s, it is possible to record external voltage signal (suchs spectroscopic signal) simultaneously with the voltammogram. Use the 9-pin D-connectoron the real panel for signal input. Check the User's Manual for the pin-out and signal levelrequirements.
8. Linear polarization resistance plot can be obtained by the Special Plots command underthe Graphics menu.
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Parameters for Staircase Voltammetry
In Staircase Voltammetry (SCV), potential is increment from Init E toward Final E. Thepotential may be scanned back. The following diagram shows the potential waveform applied asthe function of time. The current is sampled at every potential increment and recorded as thefunction of potential.
Potential(V)Final EIncr E
Init E
Sample WidthSegment 1
Step PeriodSegment 2
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Incr E (V)
Segments
Range-10 - +10-10 - +101e-3 - 0.05
1 - 10000
DescriptionInitial potentialFinal potential
Increment potential of each step
Number of scan segments
Sampling Width (sec)Step Period (sec)Quiet Time (sec)Sensitivity (A/V)1e-4 - 500.001 - 500 - 1000001e-12 - 0.1Data sampling width for each pointPotential step period or dropping timeQuiescent time before potential scanSensitivity scale
Notes:
1.Init E and Final E should be at least 0.01 V apart.
2.Sampling Width should be no more than half of Step Period, otherwise the system willautomatically readjust Sampling Width.
3.Data sampling always occurs at the end of each step.
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Parameters for Tafel Plot
In Tafel Plot (TAFEL), potential is scanned from Init E toward Final E. The potentialmay be scanned back. The following diagram shows the potential waveform applied as thefunction of time. The logarithm of current is recorded as the function of potential.
Final E
Potential(V)Hold Time
Scan Rate (V/s)
Init E
Segment 1
Segment 2
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)
Sweep Segments
Hold Time at Final E (s)Scan Rate (V/s)Quiet Time (sec)Sensitivity (A/V)Auto Sens
Range-10 - +10-10 - +101 - 2
0 - 1000001e-6 - 0.10 - 1000001e-12 - 0.1Check orUncheck
DescriptionInitial potentialFinal potential
Sweep segments, each segments is half cyclePotential hold time atfer 1st sweep segentPotential scan rate
Quiescent time before potential scanSensitivity scale
Automatic sensitivity switching during run
Notes:
1.Init E and Final E should be at least 0.01 V apart.
2.Corrosion rate calculation can be obtained by Special Analysis command under theAnalysis menu.
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Parameters for Chronoamperometry
In Chronoamperometry (CA), potential is stepped from Init E toward either High E orLow E depending on the Init P/N. The potential will then step back. The following diagramshows the potential waveform applied as the function of time. The current is recorded as thefunction of time.
High EHigh E
Potential(V)Pulse Width
Init E
Pulse Width
Low E
Step1
0
Step2Step 3
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)High E (V)Low E (V)Init P/N
Number of StepsPulse Width (sec)Sample Interval (s)Quiet Time (sec)Sensitivity (A/V)Auxiliary SignalRecording
Range-10 - +10-10 - +10-10 - +10
Positive or Negative1 - 3201e-4 - 10001e-6 - 100 - 1000001e-12 - 0.1
Check or Uncheck
DescriptionInitial potential
High limit of potential scanLow limit of potential scanInitial step direction
Number of potential stepsPotential pulse widthSampling Interval
Quiescent time before potential stepSensitivity scale
Simultaneously external signal
recording when the sample interval isgreater than 0.005 s
Notes:
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________________________________________________________________________1.High E and Low E should be at least 0.01 V apart.
2.If unreasonable High E and Low E are entered, the system will automatically readjustthem.
3.Depending on the Init E, High E and Low E value, the system will automatically readjustinitial step direction.
4.The maximum potential step range is 13.1 V.
5.Shorter sample interval will increase data density, but will reduce the signal-noise ratio.If earlier transient data is important, shorter sample interval is recommended. If the later partof data is of interest, longer sample interval is recommended. However, minimum 100 pointsper step are required.
6.If the sample interval is less than 0.002s, the data will not be transferred on the real-timebase. Instead the data will be transferred after the experiment is completed. Cell is turned offduring the data transfer unless the Cell On between Run option is selected. From start ofexperiment and data transfer there is a delay. The total number of data points will be limitedto 64K due to internal memory size limitation. Sample interval might be automaticallyaltered to adjust the data points in the reasonable range.
7.If the sample interval is longer than 0.002s, data will be transferred during experiment.Maximum 64K total data points are allowed for each step. Sample interval might beautomatically altered to adjust the data points in the reasonable range.
8.If the sample interval is greater than 0.005s, it is possible to record external voltagesignal (such s spectroscopic signal) simultaneously with the current. Use the 9-pin D-connector on the real panel for signal input. Check the Appendix of the User's Manual for thepin out.
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Parameters for Chronocoulometry
In Chronocoulometry (CC), potential is stepped from Init E toward Fianl E. The potentialmay step back. The following diagram shows the potential waveform applied as the function oftime. The charge passing through the working electrode is recorded as the function of time.
Final EFinal E
Potential(V)Pulse WidthPulse Width
Init E
Step 1
0
Init E
Step 2Step 3
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)
Number of StepsPulse Width (sec)Sample Interval (s)Quiet Time (sec)Sensitivity (C orA/V)
Range-10 - +10-10 - +101 - 3201e-4 - 10001e-6 - 100 - 1000001e-12 - 0.1or 1e-9C/V -1e-6 C/V
DescriptionInitial potentialFinal potential
Number of potential stepsPotential pulse widthSampling Interval
Quiescent time before potential stepSensitivity scale
Notes:
1.Init E and Final E should be at least 0.01 V apart.2.The maximum potential step range is 13.1 V.
3.A true integrator (charge-to-voltage converter) can be chosen. In this case, the sensitivityis 1e-9C/V to 1e-6C/V. If the charge exceeds the 8e-6 coulomb, the capacitor of the
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Chapter 4. Setup Menu
________________________________________________________________________integrator will be discharged and the new charge will be added to the previous value. Thisallows higher charge to be measured with the integrator. There might be discontinuity incharge-time curve due to the capacitor discharge. The discontinuity should be negligible.However, if it is significant to the measurement, you may choose to use the current-to-voltage converter and integrate the current measured by software.
4.Current-to-voltage converter is not ideal for chronocoulometry, particularly if the earlytransient data is important, such as double layer capacitance, or surface reactions. Charge-to-voltage converter (true integrator) is a better choice.
5. If current-to-voltage converter is selected due to high total charge, shorter sample intervalwill increase data density, but will reduce the signal-to-noise ratio. If earlier transient data isimportant, shorter sample interval is recommended. If the later part of data is of interest,longer sample interval is recommended. However, minimum 1000 points per step arerequired, unless sampling rate does not allow it.
6.If the sample interval is less than 0.002s, the data will not be transferred on the real-timebase. Instead the data will be transferred after the experiment is completed. Cell is turned offduring the data transfer unless the Cell On between Run option is selected. From start ofexperiment and data transfer there is a delay. The total number of data points will be limitedto 64K due to internal memory size limitation. Sample interval might be automaticallyaltered to adjust the data points in the reasonable range.
7.If the sample interval is longer than 0.002s, data will be transferred during experiment.Maximum 64K total data points are allowed for each step. Sample interval might beautomatically altered to adjust the data points in the reasonable range.
8.If the current-to-voltage converter is used, during the run, an “Overflow” warning mightappear. This is due to the current transient immediately after the potential step. If the
intercept (that gives information of double layer capacitance and adsorption) of Anson plot(Q-t1/2 plot) is not your primary interest, you may not worry about it. However, if the datadistortion can be seen visually, you have to lower the sensitivity scale.
Sometimes, you may use i/E converter filter to slow the system down, but make sure thatthe time constant of the filter (1/cutoff freq) is much shorter than the pulse width.In order to reduce noise and enhance the accuracy of the measurement, it isrecommended to use the highest sensitivity scale possible.
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Parameters for Differential Pulse Voltammetry
In Differential Pulse Voltammetry (DPV), the base potential is incremented from Init Etoward Final E. A potential pulse is applied. The current before the potential pulse and at the endof the potential pulse are sampled. The difference of these two current samples is recorded as thefunction of potential. The following diagram shows the potential waveform applied as thefunction of time and the current sampling scheme.
Potential(V)Pulse Width
Amplitude
Final E
Incr EInit E
Pulse Period
Sample Width
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Incr E (V)Amplitude (V)Pulse Width (sec)Sampling Width (sec)Pulse Period (sec)Quiet Time (sec)Sensitivity (A/V)
Range-10 - +10-10 - +10±0.001 - ±0.050.001 - 0.50.001 - 101e-4 - 100.01 - 500 - 1000001e-12 - 0.1
DescriptionInitial potentialFinal potential
Increment potential of each pointPotential pulse amplitudePotential pulse widthData sampling width
Potential pulse period or dropping timeQuiescent time before potential scanSensitivity scale
Notes:
1.Init E and Final E should be at least 0.01 V apart.
2.Pulse Width should be no more than half of Pulse Period, otherwise the system willautomatically readjust Pulse Width.
3.Sampling Width should be no more than half of Pulse Width, otherwise the system willautomatically readjust Sampling Width.
4.When amplitude is negative, the pulse direction is different from the potential scandirection.
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Parameters for Normal Pulse Voltammetry
In Normal Pulse Voltammetry (NPV), the base potential is held at Init E. A sequence ofpotential pulse with increasing amplitude is applied. The current at the end of the potential pulseis sampled. This current is recoded as the function of the pulsed potential. The following
diagram shows the potential waveform applied as the function of time and the current samplingscheme.
Potential(V)Pulse Width
Incr E
Init E
Pulse Period
Sample Width
Final E
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Incr E (V)
Pulse Width (sec)Sampling Width (sec)Pulse Period (sec)Quiet Time (sec)Sensitivity (A/V)
Range-10 - +10-10 - +100.001 - 0.050.001 - 101e-4 - 100.01 - 500 - 1000001e-12 - 0.1
DescriptionInitial potentialFinal potential
Increment potential of each pointPotential pulse widthData sampling width
Potential pulse period or dropping timeQuiescent time before potential scanSensitivity scale
Notes:
1.Init E and Final E should be at least 0.01 V apart.
2.Pulse Width should be no more than half of Pulse Period, otherwise the system willautomatically readjust Pulse Width.
3.Sampling Width should be no more than half of Pulse Width, otherwise the system willautomatically readjust Sampling Width.
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Parameters for Differential Normal Pulse Voltammetry
In Differential Normal Pulse Voltammetry (DNPV), the base potential is held at Init E. Asequence of dual potential pulses are applied. The first pulse will increment its magnitude foreach pulse. The second pulse has the constant amplitude. The current at the end of two potentialpulses are sampled. The difference of these two current is recoded as the function of the firstpulsed potential. The following diagram shows the potential waveform applied as the function oftime and the current sampling scheme.
Potential(V)Pulse WidthPulse Width
Final EIncr E
Init E
Amplitude
Pulse PeriodSample Width
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Incr E (V)Amplitude (V)
1st Pulse Width (sec)2nd Pulse Width (sec)Sampling Width (sec)Pulse Period (sec)Quiet Time (sec)Sensitivity (A/V)
Open Circuit at Initial E
Range-10 - +10-10 - +100.001 - 0.050.001 - 0.50.01 - 100.01 - 100.001 - 50.05 - 500 - 1000001e-12 - 0.1Check oruncheck
DescriptionInitial potentialFinal potential
Increment potential of each pointPotential pulse amplitudeFirst potential pulse widthSecond potential pulse widthData sampling width
Potential pulse period or dropping timeQuiescent time before potential scanSensitivity scale
Step 1 could be either held at a constantpotential or open circuit
Notes:
1.Init E and Final E should be at least 0.01 V apart.
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Chapter 4. Setup Menu
________________________________________________________________________2.In Differential Normal Pulse Voltammetry, the potential of first step is normally held atInitial E where no electrochemical reaction will occur. The second step is incremented everycycle. A current sample is taken at the later part of the period. The potential of the third isalso incremented like the second step, but it is more positive (for positive scan) or morenegative (for negative scan) than the second potential by a constant magnitude (amplitude).The second sample is taken at the later part of the period. The difference between the twocurrent samples is reported as the function of the second potential.
3.Pulse Width should be no more than half of Pulse Period, otherwise the system willautomatically readjust Pulse Width.
4.Sampling Width should be no more than half of Pulse Width, otherwise the system willautomatically readjust Sampling Width.
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Parameters for Square Wave Voltammetry
In Square Wave Voltammetry (SWV), the base potential is increment from Init E towardsFinal E. A square wave potential is superimposed to the base potential. The base potentialincrements after each cycles of the square wave. The current at the end of forward and reversesteps are sampled. These two current are recoded as the function of the base potential. During theexperiment, only the difference of two current samples is displayed. After experiment, theforward and reverse current are also available for display. The following diagram shows thepotential waveform applied as the function of time and the current sampling scheme.
Potential(V)Incr E
Final E
AmplitudeInit E
1/Frequency
Sample Width
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Incr E (V)Amplitude (V)Frequency (Hz)Quiet Time (sec)Sensitivity (A/V)
Range-10 - +10-10 - +100.001 - 0.050.001 - 0.51 - 1000000 - 1000001e-12 - 0.1
DescriptionInitial potentialFinal potential
Increment potential of each point
Square wave amplitude, half peak-to-peakSquare wave frequency
Quiescent time before potential scanSensitivity scale
Notes:
1.Init E and Final E should be at least 0.01 V apart.
2.Forward, reverse and difference currents are recorded. Use the Graph Option commandunder the Graphics menu to choose data display options.
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Chapter 4. Setup Menu
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Parameters for A.C. Voltammetry
In AC Voltammetry (ACV), the base potential is increment from Init E towards Final E.A sequential sine waveform is superimposed to the base potential. The current is sampled whenac signal is applied and analyzed using a software lock-in amplifier. During the experiment, onlythe absolute ac current is displayed. After experiment, the phase-selective current at any phaseangle are also available for display. The following diagram shows the potential waveformapplied as the function of time.
Potential(V)Incr E
AmplitudeInit E
Sample Period
Final E
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Incr E (V)Amplitude (V)Frequency (Hz)Sample Period (sec)Quiet Time (sec)Sensitivity (A/V)Bias DC CurrentAuto Sens
Range-10 - +10-10 - +100.001 - 0.050.001 - 0.40.1 - 100001 - 65
0 - 1000001e-12 - 0.1off - range - onCheck orUncheck
DescriptionInitial potentialFinal potential
Increment potential of each pointA.C. amplitudeA.C. frequency
Data sampling period or dropping timeQuiescent time before potential scanSensitivity scale
Enable dc current bias during run
Automatic sensitivity switching during run
Notes:
1.Init E and Final E should be at least 0.01 V apart.
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________________________________________________________________________2.Depending on the frequency range, sometimes the exact frequency can not be obtained. Ifthis occurs, the closest possible frequency will be applied.
3.When frequency is 2 Hz or lower, Sample Period should be at least 2 seconds, otherwise,the system will automatically readjust Sample Period.
4.When dc current is high and ac current is low, the sensitivity can not be increasedbecause dc current will overflow. This problem is more serious when the frequency is
relatively low. By applying dc current bias, it allows higher ac signal amplification. A 16-bitDAC is used for this purpose. If dc current is not expected to be large and the frequency ishigh, one may not want to bias dc current.
5.Both absolute current and phase selective current are available. Use the Graph Optioncommand under the Graphics menu to choose data display options.
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Parameters for Second Harmonic A.C. Voltammetry
In Second Harmonic AC Voltammetry (SHACV), the base potential is increment fromInit E towards Final E. A sequential sine waveform is superimposed to the base potential. Thecurrent is sampled when ac signal is applied and its second harmonic components are analyzedusing a software lock-in amplifier. During the experiment, only the absolute second harmonic accurrent is displayed. After experiment, the phase-selective second harmonic current at any phaseangle are also available for display. The following diagram shows the potential waveformapplied as the function of time.
Potential(V)Incr E
AmplitudeInit E
Sample Period
Final E
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Incr E (V)Amplitude (V)Frequency (Hz)Sample Period (sec)Quiet Time (sec)Sensitivity (A/V)Bias DC CurrentAuto Sens
Range-10 - +10-10 - +100.001 - 0.050.001 - 0.40.1 - 50001 - 65
0 - 1000001e-12 - 0.1off - range - onCheck or Uncheck
DescriptionInitial potentialFinal potential
Increment potential of each pointA.C. amplitudeA.C. frequency
Data sampling period or dropping timeQuiescent time before potential scanSensitivity scale
Enable dc current bias during run
Automatic sensitivity switching during run
Notes:
1.Init E and Final E should be at least 0.01 V apart.
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________________________________________________________________________2.Depending on the frequency range, sometimes the exact frequency can not be obtained. Ifthis occurs, the closest possible frequency will be applied.
3.When frequency is 2 Hz or lower, Sample Period should be at least 2 seconds, otherwise,the system will automatically readjust Sample Period.
4.When dc current is high and ac current is low, the sensitivity can not be increasedbecause dc current will overflow. This problem is more serious when the frequency is
relatively low. By applying dc current bias, it allows higher ac signal amplification. A 16-bitDAC is used for this purpose. If dc current is not expected to be large and the frequency ishigh, one may not want to bias dc current.
5.Both absolute current and phase selective current are available. Use the Graph Optioncommand under the Graphics menu to choose data display options.
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Parameters for Amperometric i-t Curve
In Amperometric i-t Curve (i-t), a constant potential is applied and the current is recordedas the function of time. The following diagram shows the potential waveform applied as thefunction of time and the sample scheme.
Potential(V)Sample IntervalInit E0Run TimeTime (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)
Sample Interval (sec)Run Time (sec)Quiet Time (sec)Scales During RunSensitivity (A/V)Auxiliary SignalRecording
High Resolution ADC
Range-10 - +101e-6 - 500.001 - 5e50 - 1000001, 2, 3
1e-12 - 0.1Check orUncheckCheck orUncheck
DescriptionInitial potential
Data sample intervalTotal measurement time
Quiescent time before taking dataNumber of current display scalesSensitivity scale
Simultaneously external signalrecording when the sample intervalis greater than 0.005 s
Use high resolution ADC sampleinterval is greater than 0.002 s
Notes:
1.The data sample interval should be chosen according to the length of the experiment. Thelonger the experiment, the larger the sample interval. Long sample interval will have bettersignal averaging and less noise.
2.During experiment, whenever the data exceed the maximum allowed points, the datastorage interval will be doubled automatically. Therefore, data points will not overflow foran unexpected long experiment.
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________________________________________________________________________3.If the sample interval is greater than 0.005s, it is possible to record external voltagesignal (such s spectroscopic signal) simultaneously with the amperometric i-t response. Usethe 9-pin D-connector on the real panel for signal input. Check the User’s Manual for thepinout.
4.If the sample interval is greater than 0.002s, High resolution ADC can be used to acquiredata. High resolution ADC usually provide better signal-to-noise ratio. The data quality lessdepends on the sensitivity setting because of its higher resolution.
5.When 1 current scale is displayed during run, it will automatically fit the data in scale.When 2 current scales are displayed during run, they is 1/100 and 1/10 of full scale. When 3current scales are displayed during run, they is 1/100, 1/10, and 1/1 of full scale.
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Parameters for Differential Pulse Amperometry
In Differential Pulse Amperometry (DPA), a clean potential could be applied forelectrode conditioning with no current sampling. Two potential pulses are applied after thecleaning step and the current at the end of each pulses are recorded as the function of time.During the experiment, only the difference of two current samples is displayed. After
experiment, the current responses to the two potential pulses are also available for display. Thefollowing diagram shows the potential waveform applied as the function of time and the currentsampling scheme.
Data Sampling
Potential(V)Clean EE 1Init E
E 2Clean T
Cycle 1
0
T 1Cycle 2
T 2
Cycle 3
Time (s)
The following are the experimental parameters, their range and descriptions:ParamInit E (V)
Cleaning E (V)
Cleaning Time (sec)Pulse E1 (V)Pulse T1 (sec)Pulse E2 (V)Pulse T2 (sec)Number of CyclesQuiet Time (sec)Scales During RunSensitivity (A/V)Open Circuit DuringCleaning
Range-10 - +10-10 - +100 - 32-10 - +`0.01 - 32-10 - +10.01 - 3210 - 1000000 - 1000001, 2, 3
1e-12 - 0.1Check orUncheck
DescriptionInitial potential during quiescent timeElectrode cleaning potentialElectrode cleaning timeFirst pulse potentialFirst pulse time
Second pulse potentialSecond pulse time
Number of Repetitive CyclesQuiescent time before taking dataNumber of current display scalesSensitivity scale
Cleaning step could be either held at aconstant potential or open circuit
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Chapter 4. Setup Menu
________________________________________________________________________Notes:
1.The experimental sequence follows cleaning, first pulse, and second pulse. This sequencewill be repeated until the total number of cycles is reached or interrupted by user. There is nodata acquisition during cleaning step. If the cleaning time is zero, this step will be ignored.Data are sampled for first and second pulses and the difference is reported.
2.The data is sampled at later ½ period of pulse 1 and 2. The longer the pulse width, thelonger the sample interval. Long sample interval will have better signal averaging and lessnoise.
3.During experiment, whenever the data exceed the maximum allowed points, the datastorage interval will be doubled automatically. Therefore, data points will not overflow foran unexpected long experiment.
4.When 1 current scale is displayed during run, it will automatically fit the data in scale.When 2 current scales are displayed during run, they is 1/100 and 1/10 of full scale. When 3current scales are displayed during run, they is 1/100, 1/10, and 1/1 of full scale.
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Chapter 4. Setup Menu
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Parameters for Double Differential Pulse Amperometry
In Double Differential Pulse Amperometry (DDPA), it combines two sets of thedifferential pulse amperometry. Two sets of data will be recorded and displayed. Each setconsists of a cleaning potential without current sampling and two pulsed potential with currentsampling. The current at the end of each pulses are recorded as the function of time. During theexperiment, only the difference of two current samples is displayed. After experiment, thecurrent responses to the two potential pulses are also available for display. The following
diagram shows the potential waveform applied as the function of time and the current samplingscheme.
Data Sampling
Data Sampling
Potential(V)Clean E1E1Init E
Clean T1
T1
E2
Clean E2E3E4Clean T2T3
T4
Cycle 2
T2
Cycle 1
0
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersFirst DPA:
Cleaning E1 (V)Cleaning Time (sec)Pulse E1 (V)Pulse T1 (sec)Pulse E2 (V)Pulse T2 (sec)
Open Circuit DuringCleaning
Second DPA:Cleaning E2 (V)Cleaning Time (sec)
Range -10 - +100 - 32-10 - +10.01 - 32-10 - +10.01 - 32Check orUncheck
DescriptionElectrode cleaning potentialElectrode cleaning timeFirst pulse potentialFirst pulse time
Second pulse potentialSecond pulse time
Cleaning step 1 could be either held ata constant potential or open circuit
-10 - +100 - 32Electrode cleaning potentialElectrode cleaning time
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Chapter 4. Setup Menu
________________________________________________________________________
Pulse E3 (V)Pulse T3 (sec)Pulse E4 (V)Pulse T4 (sec)
Open Circuit DuringCleaning
Init E (V)
Number of CyclesQuiet Time (sec)Scales During RunSensitivity (A/V)
-10 - +10.01 - 32-10 - +10.01 - 32Check orUncheck-10 - +1010 - 1000000 - 1000001, 2, 3
1e-12 - 0.1
First pulse potentialFirst pulse time
Second pulse potentialSecond pulse time
Cleaning step 2 could be either held ata constant potential or open circuitInitial potential during quiescent timeNumber of Repetitive CyclesQuiescent time before taking dataNumber of current display scalesSensitivity scale
Notes:
1.The experimental sequence follows the first DPA cleaning, first pulse, and second pulse,then the second DPA cleaning, first pulse, and second pulse. This sequence will be repeateduntil the total running time is reached or interrupted by user. There is no data acquisitionduring cleaning step. If the cleaning time is zero, this step will be ignored. Data are sampledfor first and second pulses and the difference is reported. Two sets of data will be obtained.2.The data is sampled at later ½ period of pulse 1 and 2. The longer the pulse width, thelonger the sample interval. Long sample interval will have better signal averaging and lessnoise.
3.During experiment, whenever the data exceed the maximum allowed points, the datastorage interval will be doubled automatically. Therefore, data points will not overflow foran unexpected long experiment.
4.When 1 current scale is displayed during run, it will automatically fit the data in scale.When 2 current scales are displayed during run, they is 1/100 and 1/10 of full scale. When 3current scales are displayed during run, they is 1/100, 1/10, and 1/1 of full scale.
5.To display data for 1st, 2nd DPA or both, use the Graph Option command under theGraphics menu to choose data display options.
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Chapter 4. Setup Menu
________________________________________________________________________
Parameters for Triple Pulse Amperometry
In Triple Pulse Amperometry (TPA), three potential pulses are applied. First two pulsesare for electrode conditioning or cleaning. The current is sampled at the end of the third potentialpulse. The current is recorded as the function of time. The third potential pulse could be at aconstant potential, or be incremented after each cycle. The following diagram shows thepotential waveform applied as the function of time and the current sampling scheme.
Data Sampling
Potential(V)E1E3Init E
E3T1
Cycle 1
0
E2T2Cycle 2
E3T3
Cycle 3
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersE1 (V)
Duration 1 (sec)Open Circuit
Range -10 - +100 - 32Check orUncheck-10 - +100 - 32-10 - +10.01 - 320 - 0.2-10 - +10-10 - +1010 - 100000
DescriptionFirst pulse potentialFirst pulse duration
Step 1 could be either held at aconstant potential or open circuitSecond pulse potentialSecond pulse durationThird pulse potentialThird pulse durationIncrement potential
Initial potential during quiescenttime
Final potential for scan
Number of Repetitive Cycles
E2 (V)
Duration 2 (sec)E3 (V)
Duration 3 (sec)Incr E (V)Init E (V)Final E (V)
Number of Cycles
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Chapter 4. Setup Menu
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Quiet Time (sec)Scales During RunSensitivity (A/V)
0 - 1000001, 2, 3
1e-12 - 0.1
Quiescent time before taking dataNumber of current display scalesSensitivity scale
Notes:
1.The experimental sequence follows first pulse, second pulse, and third pulse. This
sequence will be repeated until the total running time is reached or interrupted by user. Thereis no data acquisition during the first and second. They are used for electrode cleaning
purposes If the first and/or second pulse time is zero, the corresponding step will be ignored.Data is sampled only for the third pulse.
2.If the increment potential is non-zero, the experiment will start at the E3 and end at theFinal E. E3 and Final E should be at least 0.01 V apart. The number of cycles will have noeffect.
3.The data is sampled at later ½ period of pulse 3. The longer the pulse width, the longerthe sample interval. Long sample interval will have better signal averaging and less noise.4.During experiment, whenever the data exceed the maximum allowed points, the datastorage interval will be doubled automatically. Therefore, data points will not overflow foran unexpected long experiment.
5.When 1 current scale is displayed during run, it will automatically fit the data in scale.When 2 current scales are displayed during run, they is 1/100 and 1/10 of full scale. When 3current scales are displayed during run, they is 1/100, 1/10, and 1/1 of full scale.
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Chapter 4. Setup Menu
________________________________________________________________________
Parameters for Integrated Pulse Amperometric Detection
In Integrated Pulse Amperometric Detection (IPAD), six segments of potential sweeps orsteps are applied. Current is sampled and integrated during the first four potential segment. Thelast two potential steps are for electrode conditioning or cleaning. The integrated current is thenaveraged and recorded as the function of time. The following diagram shows the potentialwaveform applied as the function of time and the current sampling scheme.
St 1St 2St 3St 4St 5Oxd ESt 6
Potential(V)Peak EHold ERed ECycle 2
Start E
Return EIntegration Time
Cycle 1
0
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersStep 1: StartStart E (V)
Hold Time (sec)
Range -3.276 - +3.2760.05 - 1
DescriptionStart potential (constant)
Start potential duration, Currentintegration starts 10 msec before theend of this step
Potential is scanned from Start E toPeak E
Time to scan from Start E to Peak E,Current integration continuesPotential is scanned from Peak E toReturn E. Often Return E is the sameas Start E
Time to scan from Peak E to Return E,Current integration continues
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Step2: Forward ScanPeak E (V)Scan Time (s)Step 3: Reverse ScanReturn E (V)
-3.276 - +3.2760.15 - 1
-3.276 - +3.276
Scan Time (s)0.15 - 1
Chapter 4. Setup Menu
________________________________________________________________________
Step 4: HoldHold E (V)
Hold Time (sec)Step 5: OxidationOxd E (V)Oxd Time (s)Step 6: ReductionRed E (V)Red Time (s)Number of CyclesQuiet Time (sec)Sensitivity (A/V)
-3.276 - +3.2760.05 - 1
Hold potential (constant)
Hold potential duration, Currentintegration for 10 msec and endOxidation potential for electrodetreatment
Oxidation time durationReduction potential for electrodetreatment
Reduction time duration
Number of cycles through six stepsQuiescent time before taking dataSensitivity scale
-3.276 - +3.2760.05 - 1-3.276 - +3.2760.05 - 15 - 655350 - 1000001e-12 - 0.1
Notes:
1.The experimental sequence follows starting potential, forward potential scan, reversepotential scan, hold potential, oxidation potential and reduction potential. This sequence willbe repeated until the total number of cycles are reached or interrupted by user.
2.Current is sampled during the last 10 msec of the start potential, forward scan, reversescan, and the first 10 msec of the hold potential. The current are integrated and reported.3.During experiment, whenever the data exceed the maximum allowed points, the datastorage interval will be doubled automatically. Therefore, data points will not overflow foran unexpected long experiment.
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Chapter 4. Setup Menu
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Parameters for Bulk Electrolysis with Coulometry
In Bulk Electrolysis with Coulometry (BE), a constant potential is applied and the
integrated charge is recorded as the function of time. The following diagram shows the potentialwaveform applied as the function of time and the sample scheme.
A pre-electrolysis may be applied to reduce the interference and background currentbefore the formal electrolysis.
Potential(V)Data Storage IntervalElectrolysis E0Time (s)
The following are the experimental parameters, their range and descriptions:
ParametersRangeDescription-10 - +10Electrolysis potentialElectrolysis E (V)
0 - 100Stop experiment at this current ratioEnd Current Ratio (%)
Data display and storage intervalData Storage Interval (s)0.01 - 100
-10 - +10Preelectrolysis potentialPreelectrolysis E (V)
0 - 100000Preelectrolysis timePreelectrolysis Time (s)
Notes:
1.Preelectrolysis step is allowed before the regular electrolysis. This is useful to reducesome residue current. The current at the end of preelectrolysis will be regarded as residuecurrent and it will be subtracted from the total charge to give net charge. If the preelectrolysistime is set to zero, this step is ignored. You can stop preelectrolysis at any time by invokeStop command. The regular electrolysis will follow immediately.2.Sensitivity scale will be switched automatically during experiment.
3.The current ratio is referred to the initial current. If the data storage interval is 1 second,the initial current is the average current of the first second after electrolysis.
4.If the end current ratio is zero, the electrolysis will continue forever. In order to stop theexperiment, the Stop command should be invoked.5.During the experiment, the data will be updated in a rate same as data storage interval.
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Chapter 4. Setup Menu
________________________________________________________________________6.The data storage interval should be chosen according to the length of the experiment. Thelonger the experiment, the larger the data storage interval. Long data storage interval willhave better signal averaging and less noise. However, for a thin layer cell, short data storagetime should be used in order to observe the detail of the electrolysis process.
7.During electrolysis, whenever the data exceed the maximum allowed points, the datastorage interval will be doubled automatically. Therefore, data points will not overflow foran unexpected long electrolysis.
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Chapter 4. Setup Menu
________________________________________________________________________
Parameters for Hydrodynamic Modulation Voltammetry
In Hydrodynamic Modulation Voltammetry (HMV), potential is increment from Init Etoward Final E. The following diagram shows the potential waveform applied as the function oftime. At each potential, the rotating speed of the RDE is modulated. The resulting alternatingcurrent is sampled and analyzed using a software lock-in amplifier. During the experiment, onlythe absolute ac current is displayed. After experiment, the phase-selective current at any phaseangle are also available for display. The ac current is sampled at every potential increment andrecorded as the function of potential.
Potential(V)Final E
Init EIncr ERotation speed modulation
& data sampling
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Incr E (V)
Rotation Rate (rpm)Modul Frequency (Hz)Modul Amplitude (rpm)Number of CyclesQuiet Time (sec)Sensitivity (A/V)
Range-10 - +10-10 - +100.001 - 0.020 – 100001 – 50 – 36001 – 10
0 - 1000001e-12 - 0.1
DescriptionInitial potentialFinal potential
Increment potential of each stepCenter rotation rateModulation frequency
Modulation Amplitude, see note 2Number of modulation cycles
Quiescent time before potential scanSensitivity scale
Notes:
1.Init E and Final E should be at least 0.01 V apart.
2.The actual rotation rate in hydrodynamic modulation isω1/2=ωo1/2+∆ω1/2 sin (σt)
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Chapter 4. Setup Menu
________________________________________________________________________Notice that the modulation function is not a sine wave, but more complicated. On the otherhand, it is still a periodic waveform at frequency σ (Modulation Frequency). The rotationrate is fluctuated around ωo (Rotation Rate), but the amplitude of the fluctuation is not
symmetric. The input parameter ∆ω (Modulation Amplitude) is really not the amplitude, butthe square of ∆ω1/2 in the above equation.
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Chapter 4. Setup Menu
________________________________________________________________________
Parameters for Sweep-Step Functions
In Sweep Step Functions (SSF), six potential sweeps and six potential steps can be mixedtogether. It is somewhat like a arbitrary waveform generator. The following diagram shows thepotential waveform applied as the function of time. One can skip any segment (by defaultparameter). It provides better flexibility for waveform control. The current is recorded asfunction of time. For sweep segments, it can also be presented as function of potential.
Segments:
Potential(V)12Step E
3456789101112
Final E
Init E
Scan Rate (V/s)
Time (s)
The following are the experimental parameters, their range and descriptions:ParamRangeSequence 1, 3, 5, 7, 9, 11Sweep:
-10 - +10Init E (V)
-10 - +10Final E (V)
1e-6 - 50Scan Rate (V/s)
Sequence 2, 4, 6, 8, 10, 12
Step
Step E (V)Step Time (s)Init E (V)Sweep S.I. (V)Step S.I. (s)
Quiet Time (sec)
Description
Initial potentialFinal potentialPotential scan rate
-10 - +100 - 10000-10 - +100.001 - 0.050.0001 - 10 - 100000
Step potentialStep Duration
Initial potential
Sweep function sample intervalStep function sample interval
Quiescent time before potential scan
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Chapter 4. Setup Menu
________________________________________________________________________
Sensitivity (A/V)
1e-12 - 0.1
Sensitivity scale
Notes:
1.For sweep function, if the difference of Init E and Final E is less than 0.01 V, thissegment will be ignored.
2.For step function, if the step time is less than 0.001 sec, or if the number of points is lessthan 3, this segment will be ignored. You need to increase step time or decrease sampleinterval.
3.If the scan rate for sweep function is less than 0.5 V/s, data is transferred and displayedreal time.
4.If the sample interval for step function is larger than 0.002 sec, data is transferred anddisplayed real time.
5.The potential differences of Init E, Final E and Step E should be less than 13.1 V.
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Chapter 4. Setup Menu
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Parameters for Multi-Potential Steps
In Multi-Potential Steps (STEP), twelve potential steps can be applied and cycled. Thecurrent is recorded as the function of time. The following diagram shows the potential waveformapplied as the function of time.
Steps:
Potential(V)123456789101112
Cycle 1Cycle 2
Time (s)
The following are the experimental parameters, their range and descriptions:Param
Step Sequence 1 – 12:Step E (V)Step Time (s)Init E (V)No. of CyclesSmpl Intv (s)Quiet Time (sec)Sensitivity (A/V)
Range-10 - +100 - 10000-10 - +101 - 100000.0001 - 10 - 1000001e-12 - 0.1
DescriptionStep potentialStep Duration
Initial potentialNumber of cyclesSample interval
Quiescent time before potential scanSensitivity scale
Notes:
1.If the step time is less than 0.001 sec, this step will be ignored.
2.If the step time is shorter than the sample interval, this step will be ignored.
3.Sample interval will be automatically increased if (step time * cycles / sample interval)exceeds 64K if data is transferred after experiment..
4.If the sample interval is larger than 0.002 sec, data is transferred and displayed real time.5.The potential differences of Init E, Final E and Step E should be less than 13.1 V.
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Chapter 4. Setup Menu
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Parameters for A.C. Impedance
In AC Impedance (IMP), the base potential is held constant at Init E. A sine waveform issuperimposed to the base potential. The frequency is scanned from high frequency to low
frequency with 12 components per decade frequency. The current and the potential are sampledand analyzed to obtain the real and imaginary impedance. During the experiment, Bode plot orNyquist plot can be switched by right click the mouse button. After experiment, impedance datacan be presented in various forms. The following diagram shows the potential waveform appliedas the function of time.
Potential(V)AmplitudeInit E
High FreqLow Freq
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)
High Frequency (Hz)Low Frequency (Hz)Amplitude (V)Quiet Time (sec)
Sensitivity Scale SettingTime (sec, range 1-100 Hz)Avrg (1K – 1M Hz)Avrg (1 – 999 Hz)Cycles (0.1 - 1 Hz)Cycles (0.01 - 0.1 Hz)Cycles (0.001 - 0.01 Hz)Cycles (0.0001 - 0.001 Hz)Points (All Frequencies)
Range-10 - +100.001 - 10000000.0001 – 1000000.001 – 0.40 - 100000Select1 - 101 - 41 - 2561 - 40961 - 40961 - 2561 - 162 - 100
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DescriptionInitial potential
High frequency limitLow frequency limitA.C. amplitude
Quiescent time before potential scanAutomatic or ManualMeasurement timeAverage factorsAverage factors
Number of cycles at each frequency pointNumber of cycles at each frequency pointNumber of cycles at each frequency pointNumber of cycles at each frequency pointNumber of points per decade frequency
Chapter 4. Setup Menu
________________________________________________________________________off - range - onEnable dc current bias during runBias DC Current
Notes:
1.Above 100 Hz, both current and potential are measured in order to calculate theimpedance. 12 frequency components per decade will be measured. In case of Fouriertransform, each measurement covers a decade of frequency range. Below 100 Hz, the onlycurrent is measured. The applied potential is assumed to have no extra phase shift and beaccurate.
2.When dc current is high and ac current is low, the sensitivity can not be increasedbecause dc current will overflow. This problem is more serious when the frequency is
relatively low. By applying dc current bias, it allows higher ac signal amplification. A 16-bitDAC is used for this purpose. If dc current is not expected to be large and the frequency ishigh, one may not want to bias dc current.
3. Line frequency (50/60 Hz) can interfere measurements. Use longer measurement timebetween 1-100Hz will improve data quality of the given frequency range.
4.The sensitivity scale setting is automatic by default. During the experiment, the systemtests the current size and determines the proper sensitivity scale. It usually works well. Thesensitivity scale setting can also be manually overridden. In certain cases, it may providebetter results. In this case, the sensitivity scale can be set for each decade of frequency range.The system displays the Manual Sensitivity Setting dialog box:
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Chapter 4. Setup Menu
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Parameters for Impedance - Time
In Impedance – Time (IMPT), the base potential is held constant at Init E. A sine
waveform is superimposed to the base potential. The current and the potential are sampled andanalyzed to obtain the real and imaginary impedance. The impedance is recorded as the functionof time. The following diagram shows the potential waveform applied as the function of time.
Potential(V)Amplitude
Sample Interval
Init E
Run Time
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)
Amplitude (V)Frequency (Hz)
Sample Interval (sec)Run Time (sec)
Cycles (below 10 Hz)Quiet Time (sec)Bias DC CurrentSensitivity (A/V)
Range-10 - +100.001 - 0.25
0.0001 - 1000005 - 20000100 - 5000001 - 1000 - 100000off - range - onAutomatic orManual
DescriptionInitial potentialA.C. amplitudeA.C. frequency
Data sampling intervalTotal experiment time
Number of repetitive cycles at eachfrequency
Quiescent time before sampling dataEnable dc current bias during runSensitivity scale
Notes:
1.If the sample interval is smaller than the actual time required for sampling, it will beautomatically adjusted.
2.The more the cycles, the better signal-to-noise ratio. However, it will take longer for theexperiment.
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Chapter 4. Setup Menu
________________________________________________________________________3.When dc current is high and ac current is low, the sensitivity can not be increasedbecause dc current will overflow. This problem is more serious when the frequency is
relatively low. By applying dc current bias, it allows higher ac signal amplification. A 16-bitDAC is used for this purpose. If dc current is not expected to be large and the frequency ishigh, one may not want to bias dc current.
4.The sensitivity scale setting is automatic by default. During the experiment, the systemtests the current size and determines the proper sensitivity scale. It usually works well. Thesensitivity scale setting can also be manually overridden. In certain cases, it may providebetter results.
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Chapter 4. Setup Menu
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Parameters for Impedance - Potential
In Impedance - Potential (IMPE), the base potential is increment from Init E towardsFinal E. A sequential sine waveform is superimposed to the base potential. The current and thepotential are sampled and analyzed to obtain the real and imaginary impedance. The impedanceis recorded as the function of potential. The following diagram shows the potential waveformapplied as the function of time.
Potential(V)Incr E
AmplitudeInit E
One Cycle
Final E
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersInit E (V)Final E (V)Incr E (V)Amplitude
Frequency (Hz)
Cycles (below 10 Hz)Quiet Time (sec)Bias DC CurrentSensitivity (A/V)
Range-10 - +10-10 - +100.001 - 0.250.001 - 0.4
0.0001 - 1000001 - 1000 - 100000off - range - onAutomatic orManual
DescriptionInitial potentialFinal potentialIncrement potentialA.C. amplitudeA.C. frequency
Number of repetitive cycles at eachfrequency
Quiescent time before sampling dataEnable dc current bias during runSensitivity scale
Notes:
1.When dc current is high and ac current is low, the sensitivity can not be increasedbecause dc current will overflow. This problem is more serious when the frequency is
relatively low. By applying dc current bias, it allows higher ac signal amplification. A 16-bit
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Chapter 4. Setup Menu
________________________________________________________________________DAC is used for this purpose. If dc current is not expected to be large and the frequency ishigh, one may not want to bias dc current.
2.The sensitivity scale setting is automatic by default. During the experiment, the systemtests the current size and determines the proper sensitivity scale. It usually works well. Thesensitivity scale setting can also be manually overridden. In certain cases, it may providebetter results.
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Chapter 4. Setup Menu
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Parameters for Chronopotentiometry
In Chronopotentiometry (CP), two current levels can be controlled to pass the workingelectrode. The switch of current polarity can be controlled by time or by potential. The potentialis recorded as the function of time. The following diagram shows the current waveform appliedas the function of time.
Anodic Current
Current (A)Cathodic TimeAnodic TimeCathodic Time
Cathodic Current
Cathodic Current
Segment 10
Segment 2Segment 3
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersCathodic Current (A)Anodic Current (A)High E Limit (V)Low E Limit (V)Cathodic Time (sec)Anodic Time (sec)Initial Polarity
Data Storage Intvl (sec)Number of Segments
Current Switching PriorityAuxiliary Signal Recording
Range0 - 0.250 - 0.25-10 - +10-10 - +100.05 - 1000000.05 - 100000Cathodic or Anodic0.0001 - 321 - 1000000Potential or TimeCheck or Uncheck
DescriptionControlled cathodic currentControlled anodic currentHigh potential limit valueLow potential limit valueCathodic run timeAnodic run time
Polarity for the first segmentData storage intervalNumber of half cycles
Current polarity switching controlSimultaneously external signalrecording when the sampleinterval is greater than 0.0005 s
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Chapter 4. Setup Menu
________________________________________________________________________Notes:
1.Cathodic current is for reduction, and anodic current is for oxidation. During the courseof reduction, if the Low E limit is reached, the current polarity will be automatically
switched to anodic. Similarly, if the High E Limit is reached during oxidation process, thecurrent will be automatically switched to cathodic. The number of current polarity switchingdepends on the Number of Segments. When the number of segments is reached, theexperiment stops.
2.The initial current polarity is determined by the Initial Polarity parameter.
3.During the experiment, the data will be updated in a rate same as data storage interval.4.In general, the data storage interval should be chosen according to the length of theexperiment. The longer the experiment, the larger the data storage interval. Whenever thedata exceed the maximum allowed points, the data storage interval will be doubled
automatically. Therefore, data points will not overflow for an unexpected long experiment.5.Though large number of segments is possible, the data will be stored only for first 400segments. The later segments will be displayed during the run, but will not be stored.
6.The current polarity can be switched either at the specified potential or at the specifiedtime. Cathodic and anodic time setting can be different. On the other hand, even with timepriority selected, if the limiting potential is reached, the current polarity will still be reversedin order to protect the electrode.
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Chapter 4. Setup Menu
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Parameters for Chronopotentiometry with Current Ramp
In Chronopotentiometry with Current Ramp (CPCR), a current ramp can be applied tothe working electrode. The potential is recorded as the function of time. The following diagramshows the current waveform applied as the function of time.
Final Current
Current (A)Scan Rate (A/s)
Init Current
Time (s)
The following are the experimental parameters, their range and descriptions:ParamInit Current (A)Final Current (A)Scan Rate (A/s)
Sample Interval (sec)High E Limit (V)Low E Limit (V)
Data Storage Intvl (sec)
Range-0.25 - +0.25-0.25 - +0.251e-10 - 0.010.0025 - 32-10 - +10-10 - +100.0001 - 32
DescriptionInitial currentInitial currentCurrent scan rateSampling interval
High potential limit valueLow potential limit valueData storage interval
Notes:
1.Initial Current and Final Current should be at least 1e-9A apart.
2.Positive current is for reduction, and negative current is for oxidation. During the courseof reduction, if the High E or Low E limit is reached, the experiment stops.
3.At least 10 points are required to run the experiment. Otherwise, you have to reduce thecurrent scan rate or reduce the sampling interval.
4.During the experiment, the data will be updated in a rate same as data storage interval.
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Chapter 4. Setup Menu
________________________________________________________________________5.In general, the data storage interval should be chosen according to the length of theexperiment. The longer the experiment, the larger the data storage interval. Whenever thedata exceed the maximum allowed points, the data storage interval will be doubled
automatically. Therefore, data points will not overflow for an unexpected long experiment.
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Chapter 4. Setup Menu
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Parameters for Multi-Current Steps
In Multi-Current Steps (ISTEP), twelve current steps can be applied and cycled. Thepotential is recorded as the function of time. The following diagram shows the current waveformapplied as the function of time.
Steps:
123456789101112
Current (A)Cycle 1Cycle 2
Time (s)
The following are the experimental parameters, their range and descriptions:Param
Step Sequence 1 - 12:Step i (A)Step Time (s)High E Limit (V)Low E Limit (V)No. of CyclesSmpl Intv (s)
Range
-0.25 - +0.250 - 10000-10 - +10-10 - +101 - 100000.0001 - 1
DescriptionStep currentStep durationPotential high limitPotential low limitNumber of cyclesSample interval
Notes:
1.If the step time is less than 0.001 sec, this step will be ignored.
2.If the step time is shorter than the sample interval, this step will be ignored.
3.Sample interval will be automatically increased if (step time * cycles / sample interval)exceeds 128K and if data is transferred after experiment..
4.If the sample interval is larger than 0.002 sec, data is transferred and displayed real time.5.The experiment will stop if the potential reaches either High E Limit or Low E Limit.
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Parameters for Potentiometric Stripping Analysis
In Potentiometric Stripping Analysis (PSA), a potential-controlled deposition step isapplied first. After deposition, the elements cumulated at the electrode surface is stripped out byapplying a constant current. The potential is recorded as the function of time. The followingdiagram shows the potential waveform during the deposition stage and the current waveformduring the stripping stage.
Potenital (V) or Current (A)Data Storage IntervalStripping CurrentDeposition EDeposition Time0
Time (s)
The following are the experimental parameters, their range and descriptions:ParametersDeposition E (V)
Deposition Time (sec)Final E (V)
Stripping Current (A)Sample Interval (sec)Quiet Time (sec)
Range-10 - +100 - 100000-10 - +10-0.25 - +0.250.0001 - 500 - 100000
DescriptionDeposition potentialDeposition time
Final potential, see note 2Controlled stripping currentSampling interval
Quiescent time before taking data
Notes:
1.If sample interval is less than 0.002 s, Total 64K data points are allowed. The datadensity equals to the Run Time / 64000.
2.If the final potential is reached, the experiment will automatically stop.
3.If the controlled stripping current is set to zero, the counter electrode is actually notconnected.
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________________________________________________________________________4.If the controlled stripping current is smaller than 1.0e-10A, no current will flow duringexperiment.
5.You do not have to worry about the current polarity. The system will automaticallyassign the current polarity according to the deposition potential and the final potential.Positive current is for reduction. Negative current is for oxidation.
6.In general, the data storage interval should be chosen according to the length of theexperiment. The longer the experiment, the larger the data storage interval.
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Parameters for Electrochemical Noise Measurement
In Electrochemical Noise Measurement (ECN), no waveform is applied to the
electrochemical cell. The working electrode is at the zero-resistance ammeter. Its potential is atvirtue ground (very close to ground but can not be connected to true ground). To measure
electrochemical noise, an identical electrode to the working electrode should be connected to theinstrument ground (black banana jack on the real panel labeled as GND), and immerse these twoelectrodes in the same solution. The electrochemical noise current pass through these twoelectrodes will be measured. If the potential noise needs to be measured, a reference electrodecan be added to the solution and connected to the reference clip. The counter electrode will notbe used.
The system displays an Electrochemical Noise Measurement Parameters dialog box:
The following are the experimental parameters, their range and descriptions:ParametersSample Interval (sec)Run Time (sec)Quiet Time (sec)Sensitivity (A/V)Potential Gain
Measurement Mode
Range0.1 - 1010 - 1000000 - 1000001e-12 - 0.11, 10, 100, 1000i, E or both
DescriptionSampling interval
Experiment running time
Quiescent time before sampling dataSensitivity scale
Gain Setting for potential noise measurementMeasurement mode
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Parameters for Open Circuit Potential - Time
In Open Circuit Potential – Time (OCPT), the working and reference electrodes areconnected and the potential difference between these two electrodes is recorded as the functionof the time. Since the counter electrode is not connected to the external cell, no current is passthrough the working electrode, except the bias current of the measuring amplifiers, which is inpicoamperes range.
The system displays an Open Circuit Potential - Time Parameters dialog box:
The following are the experimental parameters, their range and descriptions:ParametersRun Time (sec)
Sample Interval (sec)High E Limit (V)Low E Limit (V)
Range0.1 - 5000000.0025 - 50-10 - +10-10 - +10
DescriptionExperiment running timeSampling intervalHigh potential limitLow potential limit
Notes:
1.If high or low potential limit is reached, a warning will be given.
2.In general, the data storage interval should be chosen according to the length of theexperiment. The longer the experiment, the larger the data storage interval.
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System Command
Use this command to set up the serial communication port, current polarity, potential axisand current axis.
This command presents a System Setup dialog box:
The following options allow you to set up your system:Communication Port
Select the communication port to link the PC to the instrument.Com Port Speed
Select the communication port speed to link the PC to the instrument. Standard isguaranteed to work with any computer. Fast may or may not work with a particular
computer. When Fast is chosen, the real time data transfer will be done at higher scan rate orshorter sample interval.Current Polarity
You can either select cathodic current as positive current or anodic current as positivecurrent. You should set this before experiment, otherwise the experimental results (peaks andwaves) will not be reported properly.
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________________________________________________________________________Potential Axis
You can set positive potential axis either left or right. This is meaningful only forvoltammetric or polarographic modes.Current Axis
You can set positive current axis either up or down.Line Frequency
Set line frequency according to what is applied. This helps set default sample interval incertain techniques to reduce the interference from the line frequency.Windows
if you are using English Windows, please choose English. If you are using Chinese,Japanese, or Korean Windows, check Oriental. Oriental Windows shows slightly biggerletters than English Windows. The Technique selection field may be truncated if you selectEnglish Windows. Also oriental Windows does not support certain symbols. For instance,symbol \"µ\" will not be displayed properly. Choose oriental Windows will use \"u\" instead of\"µ\".
Data Length
The default data length is 128K. The longer the data length, the more computer resourcewill be used. It is recommended not to use long data length unless necessary. Using long datalength will need large computer memory such as 256M, 512M RAM or more. It will alsoslow down the system and prohibit other programs to run.
After you change the data length setting in the System Setup command, please exit theprogram and restart the program so that the data length can be set properly. Otherwise theprogram may crash.
If the data is acquired and saved with long data length setting, but read back with shorterdata length setting, the program may crash. Therefore once you used long data length setting,you should not set to shorter data length later. Please think carefully before you decide toincrease the data length.Save retrieve data during run
Check this option will allow data to be saved on the hard drive during run. In caseexperiment does not complete due to external interference or interruption, miss
communication, partial data can be recovered. This is useful for very slow experiments.Hours of experimental data can be recovered.
This option is not active by default. If you do not run very slow experiments, you can re-run the experiment if the experiment is interrupted by accident.
To retrieve experimental data of last run, you should use Retrieve command under theFile menu.
Present Data Override Warning
If your experimental data is not saved before running a new experiment or opening anexisting file on the disk, your unsaved data will be overridden. This option will allow systemto issue a warning before the data is lost.Save Text File As Well
Normally only binary data files is saved. Binary file contains more information
(including experimental control information) but small in size. This option allows you to
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________________________________________________________________________save text file as well whenever you save the binary data. This is useful for those who want toexport data to other software, such as spreadsheet software.Erase ADC Calibration Coefficients
The analog-to-digital converter (ADC) calibration coefficients are stored in the
instrument non-volatile memory. ADC calibration is carried out in CH Instruments before theinstrument is shipped. You use this command only if you want to recalibrate the ADC. Afteryou erase ADC calibration coefficients, you will see a prompt of ADC calibration when yourun next hardware test or experiment.
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Hardware Test Command
Use this command to test the system hardware. The system will test digital and analogcircuitry.
After the test, the system will display the Hardware Test Results dialog box:
Digital Circuitry Test
The software version and the last revision date for the Flash ROM is shown.Potential and current offset test
If test is failed, the error message will be given.Sensitivity scale test
If test is failed, the error message will be given. Most times the error is related to leakagecurrent.Gain test
There are 3 gain stages. If test is failed, the error message will be given.Analog Test Summary
The test results of analog circuitry are summarized. A message of “Analog circuitry testOK.” will appear if no error is detected, otherwise an error message will appear. In case thereis error and the cause is due to the analog-to-digital converters, it will also be reported.If you see analog test error, please repeat the test several times and see if the error isconsistent. Record the error message and contact the factory for servicing.
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