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Introduction
The PalmSensPC software can be used to control one or multiple PalmSens instruments, by means of a Personal Computer. The PC is used to specify the parameters of the measurement, to display the measured curves and calculate the results of the measurements.
The PalmSens instrument can be used with electrochemical sensors or electrochemical cells. The instrument contains a microprocessor and a low noise and low-current potentiostat/galvanostat which controls the potential or current applied to the sensor and measures the current or potential response.
In general the instrument is used with electrochemical sensors or electrochemical cells with three electrodes: working electrode, reference electrode and auxiliary or counter electrode. In the so-called two-electrode configuration the counter and reference electrodes can be combined to a single electrode. In that case the counter and reference connectors are tied together.
The instrument has an internal battery and can operate several hours without the power cable connected, when charged. However in normal use with PalmSensPC, the power cableremains connected.
Click on the figure to get detailed information:
General appearance on the PalmSensPC software:
• Top-left : the Method history box that allows the operator to quickly switch back and forth between the most commonly used measurement procedures.
• Top-right : the Main menu functions to save/load procedures & data, and to access various other functions such as Options and the Manual.
• Middle left : the Parameter definition pane containing tabsheets for Direct Control, Method definition, and Analysis parameter definition.
• Middle right : the Result pane containing tabsheets for graphical and numerical presentation of results, and performing data analysis
• Bottom : Status bar containing panels that indicate the status of the instrument and the progress of ongoing measurements.
Method history list
This feature will enable the operator to quickly switch back and forth between previously defined measurement methods. Clicking on the right arrow will display a list with the last 8 stored method files, the most recent being on top. Selecting a specific file from this list will load it.
Main menu
The main menu contains several menu items:
• File: access to file operations
• Options: access to Pretreatment and Hardware & Data options
• About : displays a dialog box with version and company information
• Help : provides information on installation, operation and data processing
Help support
Help is provided by several means:
• On the main menu, in the Help/Content submenu the online manual can be accessed.
• On the main menu, in the Help/Topic submenu, help on specific topics can be searched.
• Pressing "F1" will bring up the online manual, opened at the topic currently in focus.
• The "What's this ?" function will provide explanations of the item under the (mouse) pointer.
The "What's this ?" option can be activated in 3 ways:
• Point at the item in question, press the right-mouse button, select "What's this ?"
• Check the "?" symbol beween the method historylist and the mainmenu, the cursor will turn into a large "?", and the operator can click on the item in question. This mode must be deselected before normal operation continues, by pressing the "?" symbol again.
• The same is accomplished after selecting the "What's this ?" item in the main Help menu.
NB some screen items already use the right mouse button for other functions. In that case, the "What's this ?" option must be selected with one of the other methods.
Getting started: Installation and Setup
The installation consists of 2 stages: the installation of the USB driver and the measurement program. It is advised to install the driver first.
• First, insert the PalmSensPC installation CD in the CDROM player.
• Plug the PalmSensPC communications cable in an available USB port
• The pc will automatically attempt the load the driver. When prompted, check: "let windows find the suitable driver automatically". Depending on your operating system the process continues now automatically. For some Windows versions, you have to indicate the path to the driver manually: "/iviumusbdrivers" on the CDROM.
• Finally, run the "Setup" program that is located in the root of the PalmSensPC installation CD. You can do this in 2 ways: Either click the <Run> option on the Windows StartMenu, type "CDROM-driveletter"/setup and press <Enter>. Or, double click on the "Setup" program, located at the root of the CDROM, with the Windows Explorer.The installation wizard will guide you through the installation process.
PalmSensPC is capable of controlling many instruments with a single PC. This requires no additional installation.
IMPORTANT: In case you are upgrading from the Pocket PC version of PalmSens, please note that PalmSensPC is using the USB instead of the serial port. Furthermore, the functions of the PalmTime and PalmScan software are combined in a single program for the PC: PalmSensPC.
Minimum system requirements
• Pentium type processor, 200 MHz or higher
• Microsoft Windows 98SE, 2000 or XP
• Available USB 1.1 port
• Memory: 48MB of RAM, 128 MB recommended
• 5 MB hard disk space
• CD ROM drive
• 800 X 600 or higher resolution screen
• Mouse or other pointing device
Switching on the PalmSens instrument
Before PalmSens is used without the adapter, the batteries must be charged. Open the lid at the left-hand side of PalmSens by pressing the hinge downwards and then turning the lid.
Connect the adapter to the 'analog i/o' miniDIN-connector or dc-in connector.
When the adapter is connected the green LED is shown. During charging of the batteries, the red LED is also shown.
Switch on PalmSens by pressing the power key until the display shows: 'Selftest'.
During the test the voltage range of the instrument is tested and shown. The normal range is from approx. –2.035 V to + 2.047 V.
As soon as the display shows PwrOK, the batteries are charged and the adapter can be disconnected. The batteries have to be recharged as soon as LowBat is shown and the corresponding beep is heard.
PalmSens can be used with the adapter connected and the batteries are charged. Removing the adapter however may decrease the noise level.
The backlight of the LCD is switched on and off by using the UP key on the PalmSens keypad . Please note that the backlight will reduce the battery-operation time of PalmSens from approx. 8 hours to not more than 6 hours.
PalmSens is switched off by pressing the power key until the display shows 'Shutting down'.
Connecting PalmSens to the PC
The USB cable is used to connect the PC to the instrument. Switch on the PC and run the PalmSensPC program: From the Windows StartMenu (left-bottom of your screen), click "Programs" and "PalmSensPC".
Plug in the sensorcable to PalmSens and connect the testsensor.
In the PalmSensPC, check the connected box on the Control tab. If the Pocket PC is not able to communicate with PalmSens, the PC shows PalmSens NOT connected on the bottom statuspanel. A soon as PalmSens is found, the PC display shows the serial number of the instrument-interface, and displays the readings of the potential and if applicable also the current.
When multiple devices are attached, you can select specific instruments from the dropdown box on the Control parameter sheet. If multiple devices are to be controlled at the same time, run multiple instances of the PalmSensPC program and select a specific instrument in each program. When an instrument is connected to an application, it is not available to other applications.
Refer to Appendix 'Troubleshooting' if PalmSens remains not connected.
First measurements using the testsensor
In order to get acquainted with the instrument a testsensor is supplied which is used to perform easily reproducible measurements. Before measurements are performed connect the testsensor to the PalmSens device.
Please note that this testsensor is a standard accessory which is NOT used to measure nice curves but to test the instrument. This means that some curves may look too noisy, however this does NOT mean that the instrument performs badly. The curves must be noisy in order to see whether the noise level is too high or not.
Recording a differential pulse voltammogram
Run the program PalmSensPC. Select File from the top menu, using "Load method" PSDiffPulse. This means: select the PSDiffPulse.pms file from the loaddialog.
The measurement starts when the <Start> button is pressed on the PalmSensPC taskbar. Recorded points are shown during the scan. After the measurement is completed, the peak height is determined and shown.
Measuring the noise level of the instrument.
Select File with "Load method" PSNoiseTest from the list given. Click on the start button. A typical measured curve will be shown. Repeat the measurement but with a scan rate of 0.0500 V/s. Note that the noiselevel is lower, due to the fact that the current measurement time is longer now, which decreases the measured noiselevel.
The instrument is controlled manually on the Control tab on the parametersheet. Press 'Cell on'. Change the applied potential from E= 0.000 V to E= 0.500 V by manipulating the horizontal sider. There are three options to change the value:
Click on the slider and drag it to the desired potential.
Click right/left of the slider, to increase/decrease the voltage with 500 mV.
Use up/down cursor keys, to increase/decrease the voltage with 1 mV.
Select the current range 10 nA. The measured values of the potential and current as well as the noise are shown. Please note that the noise level has the same units as the given current value.
Recording an amperometric detection curve
From the top menu, select Load Method in the File menu. In the load dialog, select, the PalmTime Method file type and choose 'PSTime.pmt' from the list. Check the parameters on the Method tab on the parametersheet.
Start the measurement by clicking the 'Start' button on the PalmSensPC taskbar. The measured current is constant with a normal value of approx. 1-5 nA.
Direct Control
The Control tab on the parametersheet allows direct control of the instrument, and displays the measured potential and current in real time.
The operator can set:
• Current range: with the row of radiobuttons on the left.
• Potentiostatic or galvanostatic mode with E/I control
• Cell on/off
• Connect/disconnect to the indicated instrument.
• Select which instrument to connect to. (disconnect before the selection can be changed).
• With calibrate offset the instrument is calibrated.
• A slider with which a voltage or current can be applied to the cell.
• Several auxiliary functions are optionally displayed:
1 analog input,
1 analog output,
3 digital outputs and
1 digital input.
Resolution and optimal current range selection
The resolution of the measurements of the potential is 1 mV and of the current equal to 0.001 of the applied current range. The measurement range is –2.000 V to + 2.000 V and –2 to + 2 times the applied current range.
The best way of obtaining an optimal current measurement resolution is to use autoranging. A higher current range is selected when the current exceeds 1.6 times the applied current range. A lower current is selected when the measured current is lower than 0.05 times the applied current range. The selectable current ranges are specified with the current range selection bar on the Method parameter sheet. It is advised to limit the number of allowed current ranges. The first measurements are always done at the highest specified current range.
Noise
Electrochemical sensors and cells are susceptible to noise. The pane on the Controltabsheet, which displays the measured current, also shows the noise level. The background color shows whether or not the noise might deteriorate the measurement. In case the noise level is higher than 0. 1 times the selected current range, the background color is orange. In case the noise level exceeds 0.5 times the selected current range, the color is red. It is strongly advised to prevent measurements under such conditions.
Known sources of noise are:
- ac-adapters. The adapters for charging the batteries of the Pocket PC and PalmSens induce noise. Sensitive measurements may be performed without these adapters connected.
- Electrical equipment. Measurements in the vicinity of electrical equipment might be distorted by electrical interference. This might be eliminated by placing the cell in a Faraday cage which is connected to earth or ground.
- Unshielded or too long sensor- or cell cables. The connection between PalmSens and the sensor or cell should not be extended. Especially unshielded cables used with many commercially available reference electrodes may result in high noise levels. Shorten the cables when possible.
In case the noise levels remain too high, the use of a Faraday cage is required. Connect the metal cage to safety ground or to the green connector of the PalmSens sensorcable.
Noise will be more pronounced when measurement rates are increased. Therefore noise might be lowered by decreasing the scan rate or increasing the interval time of the measurement.
Status: current overload, underload and voltage overload.
The top pane on the Control tab of the parameter sheet shows measured potential (left) and current (right). Also, it indicates whether the instrument measured a current overload (Iovl), current underload (Iunl) or a voltage overload (Eovl).
Measured current values are wrong when a current overload is detected. This occurs when the current is below -2 or above +2 times the applied current. However the warning is given already at lower values. If currents are below 0.05 of the selected current, a current underload is given, since a lower current range can be applied. An underload will yield measurements with a low resolution.Voltage overload means that the impedance between the counter and the reference electrode is too high. This can be found when:
• the counter or the reference electrode is not properly connected
• the conductivity of the solution is too low, which is overcome by adding an electrolyte, an air bubble isolates the reference electrode from the solution.
Performing measurements
The PalmSensPC program provides the possibility to apply all relevant voltammetric techniques as well as stripping chronopotentiometry (SCP) or PSA. These techniques can be used in their stripping modes for traceanalysis. Furthermore, the program provides the possibility to measure current as a function of time, which I used in general for electrochemical detection.
The applicable techniques are:
Linear sweep voltammetry LSV
Differential pulse voltammetry DPV
Square wave voltammetry SWV
Normal pulse voltammetry NPV
ac Voltammetry acV
Cyclic voltammetry CV
Stripping Chronopotentiometry (or PSA) SCP
Amperometric detection AD
Pulsed amperometric detection PAD
The technique can be selected from the method selection drop down list at the Method parameter tabsheet:
When the start button is pressed, the measurement sequence is started.
After the sequence is completed, E st.by is applied if the cell must remain switched on, otherwise the cell is switched off.
Theoretical background of these methods can be found in:
• Christopher M.A. Brett and Ana Maria Oliveira Brett, Electroanalysis (Oxford Chemistry Printers, 64) Oxford SciencePublications, ISBN 0-19-854816-8
• Christopher M.A. Brett and Ana Maria Oliveira Brett, Electrochemistry: Principles, Methods and Applications from Oxford Science Publications, ISBN 0-19-855388-9.
• Joseph Wang, Analytical Electrochemistry, John Wiley & Sons, ISBN 0471282723
Sequence of a measurement
The sequence of a potential scan measurement (except stripping chronopotentiometry and ) is:
• Apply E_cond, the conditioning potential, if t cond is not zero.
• Apply E_dep, the deposition potential, if t dep is not zero.
• Apply E_begin or E_equi and wait t_equi seconds
• Start measurement at E_start and continue until E end with steps E step, with the specified scan rate. In CV the scan is continued by reversing the scan direction. The current range is set automatically however with the constraints as specified on the Method tab of the parameter tabsheet.
• If the measurement rate is less then 25 points per second the points are displayed on-line. During the measurement the plot can be re-scaled automatically. If the scan rate is higher the points are plotted after completing the scan.
• If the cell must remain switched on, E st.by is applied, otherwise the cell is switched off
The sequence of stripping chronopotentiometry (SCP or PSA) is:
• Apply E_cond, the conditioning potential, if t_cond is not zero.
• Apply E_dep, the deposition potential, if t_dep is not zero.
• Apply E_dep and wait t eq seconds.
• If I strip = 0 then the cell is switched off, otherwise a constant current Istrip is applied. The measurement with a rate of 40 kHz starts. The measurement stops when either the measured potential is below E end or t meas is exceeded.
• If the cell must remain switched on, E_stby is applied, otherwise the cell is switched off
The sequence for amperometry (CA or PAD):
• Apply E_cond the conditioning potential, if t cond is not zero.
• Apply E_dep the deposition potential, if t dep is not zero.
• Apply E_begin or E_equi and wait t_equi seconds.
• Start the measurement. The measured points are displayed on-line.
• If the cell must remain switched on, E st.by is applied, otherwise the cell is switched off.
During the conditioning, deposition and equilibration stages two keys of the keypad or active. When ESC is pressed the measurement is ended. The > key is used to step to the next stage. During a measurement only the ESC key is active. On the PC, you can press <skip pretreatment> to immediately proceed to the measurement stage, or <abort> to end the measurement.
After each measurement the curve is smoothed (see main menu Options/Options/Data treatment) and an automatic peak search is done. The detected peaks are identified according to the parameters specified in Data treatment dialog. Indicated above. For the detection techniques: AD and PAD, either peaks or stationary current levels are detected using the parameters specified on the Calibration tab of the resultsheet.
For the relevant techniques: the program allows determinations by means of standard addition or by using a calibration curve. In case a calibration curve is used, this curve is measured first or loaded from the list shown by selecting File ? Load analysis. A calibration curve requires measurement of one or more standard solutions.
File menu
1. Load method allows to load a predefined set of parameters for the measurement and analysis.
2. Save method allows to save a defined set of parameters for the measurement and analysis.
3. Load data gives the possibility to load a measured curve.
4. Save data curve gives the possibility to save the curve measured with the sample.
5. Load analysis allows to load all measured curves and the corresponding peak heights necessary for a complete determination.
6. Save analysis allows to store the measured curves and the peak heights used for the determination.
7. Exit ends the program.
Options menu
Options is used to define the hardware configuration of the instrument, and the data treatment parameters:
• Hwconfig: specify which hardware options are attached, such as Stirrer, Multiplexer, BiPotentiostat, etc. Also, you should specify which is frequency of the power grid in your area: 50/60Hz, to enable a more efficient noise reduction.
• Data treatment: to specify whether automatic spike rejection is applied, and which degree of smoothing is applied. Furthermore, the parameters for automatic peaksearch can be specified.
Pretreatment
Pretreatment can be used to apply a series of potentials to the sensor. During the pretreatment stages the potentials and currents can be read from the Controltabsheet. When current overloads are measured, the currentrange is automatically increased, and likewise decreased after underload conditions. After the pretreatment ends, the last applied potential is maintained if the option "cell on after measurement" on the Method tab of the parametersheet is checked, else the cell is disconnected.
PalmSensPC taskbar
Measurements can be controlled with the taskbar buttons at the bottom of the Result graph sheet . Which buttons are available, depends on the used technique and the stage of the measurements:
• <start>: starts a measurement, available when no measurement is in progress
• <abort>: aborts a measurement, available while a measurement is in progress
• <skip pretreatment>: skip the ongoing deposition and condition stages
• <start blank>: start measurement of a blank
• <hold>: pauses/continues the recording of data, available for AD and PAD, depressing the button continues the recording.
• <null offset>: option to subtract the present current from the subsequent measurements, available for AD and PAD, can be cancelled by depressing the button.
PalmSensPC statusbar
The statusbar located at the bottom of the PalmSensPC window show status information about the instrument and the measurement in progress:
• Connection panel: indicates which instrument is currently connected.
• Control status panel: indicates whether the instrument is under "direct" control, or a measurement procedure "method control" is ongoing.
• Data status panel: indicates how many data points with over-/under-loads have been recorded during the current scan.
• Data points panel: indicates the total number of recorded datapoints
• Cycle panel: indicates the current cycle number (CV).
• Progress panel: indicates the completion ratio, and estimates the remaining measurement time.
Method parametersheet
The method parameters are specified on the parameter pane (left) on the tabsheet with the caption "Method" . Which parameters are available (=visible) depends on the selected technique.
The method can be selected from the dropdownlist at the top. For applicable techniques, there is the option to check the standard addition checkbox. The "sample" and the "sensor" boxes can be edited, and will be stored with the data. The "sample" text will appear as title above the resultplot.
Left row with potentials:
E_begin Potential where scan start (not for SCP)The applicable range of the potential is –2 V to +2 V.
E_end Potential where measurement stops, in CV potential where scandirection reverses.
E_step Step potential (not for CP)
E_pulse Pulse potential (DPV only)
E_amp Amplitude (of square wave pulse (SWV) and sine wave (acV). Values are half peak-to-peak (SWV) or rms (acV).
I_strip Stripping current (CP only). If specified as 0, the method is called chemical stripping otherwise it is constant current stripping.
The applicable range is ± 0.001 µA to ± 2 mA.
E_cond Potential applied before the deposition stage is started. Is only relevant when t_cond > 0 s.
E_dep Potential applied during the deposition stage. Is only relevant when t_dep > 0 s.
E_stby Potential applied after a measurement (see below).
Right row with time related parameters:
scanrate The applied scan rate. The applicable range depends on the value of E_step.
t_pulse The pulse time in DPV and NPV
t_meas Maximum measurement time in SCP. This value should always exceed the required measurement time. It is only used to limit the time of measurement. When the potential response is erroneously and E end is not found within this time, the measurement is aborted.
Freq The frequency of the square wave or ac signal.
t_cond Conditioning time.
t_dep Deposition time
t_equi Equilibration time. During this stage E_start is applied.
t_int Time between two measurements
t_pulse The pulse time in PAD and FA
t_run Total time of measurement.
measure 1: i(dc) measurement is performed at potential E
2: i(pulse) measurement is performed at potential E pulse
3: i(dif) measurement is i(dc) – i(pulse)
When the "cell on after measurement" is checked, the E_stby will be applied after the measurement.
Blank subtraction can be selected, either with a separate file (from disk or measured), or using "Subtractive Stripping" .
The blue bar at the bottom gives the allowed current ranges that can be applied during the measurement. The measurement will start with the maximum selected current range, and will change automatically to lower ranges if the measured result allows this. The operator can define the minimum and maximum allowed range by pressing the buttons below the blue bar. If autoranging is undesirable, a single current range should be selected by pressing the same range button twice.
During the measurement a slider will appear that indicates the actual used range.
Std.addition parametersheet
When the Standard addition is selected on the Method tab of the parameter sheet, an extra sheet appears with the caption: "Std addition". Another "Std addition" sheet will appear on the result pane on the right, which is explained with the Std. Addition result tabsheet.
Standard Addition/calibration is used to select the method of standard addition or using a calibration.
Cell volume (in ml) is required to correct for dilution effect due to the addition of the standard solutions and to calculate the concentration in the original sample.
Sample volume (in ml) is used to calculate the concentration in the original sample from the peak height measured in the solution specified in the box of the cell volume.
Conc. unit: any text can be specified. It is not used for the calculations but only to report the results.
Id: The identification box specifies the component name.
Sol#: The number to be specified corresponds to a standard solution. In case one standard solution for one or more components is used the number is 1. If more than one component is analyzed the number can be higher. Each component can have its own standard solution number.
Epeak specifies the estimated peak potential. A peak is identified as specified component if the measured peak potential is within the peak window (see Options/Options/Data treatment ).
Conc.: Specifies the concentration, given in 'Unit of concentration', of the component in the corresponding standard solution. These parameters are only relevant when the standard addition method is applied.
St.1- St. 4 The table is used to specify the volume of the standard additions or the concentration of a calibration solution. If the method is standard addition, the values are given in µl. When a calibration is used, the values are given in units of the concentration as specified above.
Standard additions table: The second table is used define and execute the additions. The checkboxes are only relevant if measured curves are available. The box is checked when a curve has been measured. A checked box means that the peaks found in the corresponding curve are used for the calculation of the concentration. In case the peaks have to be omitted, remove the check. The quantity fields are automatically calculated from the table above. The buttons on the right are used to start the measurement of the additions. Before measurement, their captions read "start" , which changes for "redo" when the specific scan is available.
To perform a valid standard addition measurement and analysis:
• The tabsheet above should be fully filled in.
• Optionally a blank should be measured, or read from file,
• A sample should be measured.
• At least 1 standard solution (2 for calibration) should be measured by pressing on of the <start>/<redo> buttons on this sheet, or loaded from file.
Data analysis and reporting
Data analysis and reporting is done at the Result pane, located on the right hand side of the PalmSensPC program window. It contains several sheets :
• Result graph sheet
• Result data sheet
• Std. addition result sheet
• Calibration sheet
Result graph sheet
The Result graph is the central point where the measured data is displayed. Also, it contains controlbar at the top, a panel with legends on the right and the PalmSensPC taskbar at the bottom.
The top panel has 2 sections, the first affects the appearance of the graph, and the second enables operations on the data :
Graph appearance buttons:
• <2D>,<2D+>,<3D> : selects the format of the graph, <2D> is a conventional plot, <2D+> adds a spacial effect, and <3D> draws the data in 3D space using the scan/cycle/overlay-index as the 3rd axis parameter.
• Options : opens a dialog that enables the operator to change the appearance of the graphical objects : colors, texts, grids, 3D-angles, etc.
• Scale : pressing on the scale button will negate any fixed scaling and performs automatic scaling. When the dropdown arrow is pressed, a dialog will pop up that allows the operator to set a scale manually, and change the style of each axis : linear/logarithmic/sqr/sqrt etc.
In addition to the manual scaling option, features in the graph can also be blown up with the mouse pointer, see zoom graph.
When the <Edit> button is pressed several options appear :
• Delete previous graphs : removes all but the most recent scan from the graph.
• Copy graph : will copy the graph as a picture (wmf) to the Windows clipboard. Now it is available for pasting into other Windows applications.
• Remove spikes : will remove spikes from the currently selected scan, selection is done from the Legend list.
• Smooth : will apply smoothing on the currently selected scan, selection is done in the Legend list.
• Revert to raw data : will restore the original data, any smoothing or spike rejection will be undone.
When the <peaks> button is pressed, the peaks/dc-levels will determined and shown for all available scans. When the dropdown arrow is pressed, 2 options appear :
• Remove all peaks : will remove the currently determined peaks
• Set peak manually : will open a window that enables the operator to determine the peak positions of the selected scan (Legends) manually.
Zoom graph
Features in graphs can be blown up by selecting the interesting area with the mouse or other pointing device. Left-click on the graph, keep the button pressed, and drag the dotted rectangle over the desired area. When releasing the button, the selected area will be enlarged. If the result is unsatisfactory, simple perform an autoscale by pressing the <Scale> button on the top bar.
Manual peak selection
Using the manual peak selection window, peak positions can be set manually. With the mouse, click on 2 or 3 points on the desired positions, and press <add selected peak>. When using 2 points, these will be interpreted as the left and right peak sides, and the top position is calculated. When using 3 points, the middle point is taken as the peak top position. When applied to CV, the reverse scan should be selected with the « CV reverse scan » checkbox before it can be edited.
Legends
All data visible in the Result graphs is also represented in the Legend panes, either as Scan or as Overlay. Scans are measurements that are recorded in the current session, which can be edited, analyzed and stored. Overlays are previously measured scans, that are read from file, which are used for visual inspection.
The legend pane can be be resized/hidden by the operator. To resize with the pointer, drag the left border of the Legend pane to the left to enlarge, or to the right to decrease size. Below a certain size, the pane will be hidden completely. A hidden legend pane can be made to appear by dragging the right Graph window border to the left.
The Scans are numbered: Scan 1, Scan 2, etc., Scan 1 being the most recent measurement. When Standard addition is activated, the Scans appear as Sample, Std.1, Std.2, Std.3 and Std.4. When specific Scans are saved, the filename will be displayed within [] brackets.
The Overlays are always read from file and will be listed with their filenames in the order that these were loaded.
The legend panes offer several options/functions :
• Visible checkbox : the checkmark indicates whether the data should be visible in the plot. The operator can uncheck this to hide specific data.
• Selection list : the operator can select a specific Scan or Overlay, which will be highlighted in blue. Any load, save or delete/remove action will be operated on this Scan/Overlay only. For Scans, this selection will also be used for smoothing and spike rejection.
• <Save data> : will save the selected scan. This has the same function as Save data in the File submenu in the mainmenu.
• <Load> : will read a measurement file from disk, and add it to the Overlay list.
• <Options> : will open a dialog that will allow the operator to choose how the data should appear in the graph : linestyles, symbols, colors, etc
Note that the Options for Overlays and Scans are independent. Their appearances can thus be made distinct, for example: lines and symbols. The Scan Options are retained after a session, but the Overlay Options are reset to the defaults.
Result data sheet
The Result data sheet will contain the numerical presentation of the Scan-data on the Result graph sheet, and the numerical results of the peaksearch. On top, a bar with several options is available:
• <meas.data> : the results of the measurements are displayed.
• <peakdata> : the peak positions identifications and calculated concentrations are displayed (when applicable).
• <copy> : will copy the numerical data to the Windows clipboard, (with tabs between the columns, which is standard for MS Excel) to make it available to other applications. The dropdown arrow allows for 2 options : copy the whole grid, or only copy the selected cells.
Also a current-unit selection bar is available from which the operator can select the units pA/nA/uA/mA in which the currents are displayed.
Std addition result sheet
When at least 1 standard (2 for calibration) and a sample has been measured, the standard addition analysis can be calculated, as is presented on the Std addition result sheet. The right table shows the peak assignments and the calculated dilution factors, and the left table displays the found concentrations for each species and the confidence limits. The row of buttons between the tables allows the operator to choose which standard addition plot should be shown. The Standard addition plot shows the measured peak heights vs the added concentration of the species, and the linear regression line. From the linear regression, the concentration in the sample is determined and shown.
The arrow beside the <copy> button above the table, enables copying both tables the Windows clipboard, as numerical data (tab delimited). The <copy graph> button will copy the standard addition plot to the clipboard, as a picture (wmf).
The concentration of a specific component is calculated from the peak heights determined in the measured curves for the sample and standards. The peak height is first corrected by the dilution factor . This value is determined by value of the cell volume and the added volume of the standard solution(s). The addition of standard solutions causes a dilution, for which the peak heights have to be corrected.
These corrected peak heights are used for linear regression calculations. The obtained value of the concentration is than multiplied by ( cell volume/sample volume) in order to determine the concentration in the original sample.
Calibration result tabsheet
The calibration sheet is only available for the techniques AD and PAD. It enables the creation and application of calibration files.
• File : to load an existing calibration file, or save present calibration file.
• Analyte : text to be saved with the file
• Unit of concentration : unit to be used for concentration.
• Create calibration curve from standards : uses the present measurement (see result graph) and applies this on the list of standard concentrations, and creates a new calibration polynomial.
• Standards : list of concentrations that is used to measure the calibration curve.
• Signal : select the shape of the response signal.
• Reaction : select the sign of the signal (negative currents for reduction, positive currents for oxidation).
• Replications : number of times that each standard measurement is repeated, only applicable for peak signals.
• Calibration curve (radio button group): selects the degree of the calibration polynomial.
• Coefficient table : displays the coefficients of the calibration polynomial, and the correlation coefficient.
• Calibration curve table : shows datapoints of the calibrationcurve.
• Calibration curve graph : shows datapoints of the calibrationcurve and the fitted calibration polynomial.
The calibration results will be applied on subsequent measurements. The thus calculated concentrations are shown on the Result data sheet, after selection of peak data.
PalmSens instrumental specifications
Controlled potential mode (potentiostat)
- dc-potential range ± 2 V
- compliance voltage ± 7 V
- dc-potential resolution 1 mV
- dc-offset error 2 mV
- accuracy = 0.2 %
- ac-potential amplitude 1 mV to 250 mV
- current ranges 1 nA to 1 mA (7 ranges)
- maximum current ± 10 mA
± 2 mA measured
- current resolution 0.1 % of current range
1 pA on lowest current range
- accuracy = 0.3 % of current range at 100 nA to 1 mA
= 0.5 % at 10 nA and = 1 % at 1 nA, all with additional 0.2 % offset error
Controlled current mode (galvanostat)
- current ranges 1 µA to 1 mA
- dc-current range -2 to + 2 times selected current range
- dc-current resolution 0.1 % of selected current range
- dc-offset error = 0.2 %
- current accuracy = 0.4 %
- maximum output voltage ± 7 V
General:
- electrometer amplifier input > 100 Gohm // 4 pF
- rise time approx. 50 µs
Keypad LEFT RIGHT UP DOWN ENTER ESC and Power (7 keys)
Display 4 lines of 16 characters with backlight
Dimensions 155 mm x 85 mm x 35 mm
Temperature range 0º C to + 40º C
Weight 0.43 kg
Power Power cable with adapter, or
2 AA cells NiMH 1800 mAh for 6-8 hours operation.
battery charger included (6 V- 1500 mA)
Interfacing USB to PC
External I/O Miniature DIN connector:
1 analog output and 1 analog input channel (0 V - 4.096 V)
3 digital output lines
1 digital input line
Maximum rating: -0.3 V to 5.3 V
Options:
CH8 multiplexer for multisensor applications up to 8 channels
All electrodes are either at same potential or all not-selected electrodes are at open-circuit potential.
Sensor and miniDIN connectors
Pinout of miniature DIN connector:
Front view of male plug: Solder side of male plug
7 O O 9 9 O O O 7
3 O O O O 6 6 O O O O 3
1 O O 2 2 O O 1
pin 1 Vadapter (6 V- 1.5 A)
pin 2 analog ground
pin 3 d0 digital output (maximum current 5 mA source or sink)
pin 4 d1 digital output (maximum current 5 mA source or sink)
pin 5 d2 digital output (maximum current 5 mA source or sink)
pin 6 d0 digital input
pin 7 auxiliary analog input
pin 8 auxiliary analog output (adviced resistive load > 10 kohm)
pin 9 5 V digital power line (maximum current 100 mA)
shield digital ground
Maximum ratings:
Digital input and output lines: -0.3 V to 5.3 V
Analog input and output lines: -0.3 V to 5.3 V
Pinout of sensor connector:
Front view of male plug: Solder side of male plug:
U U
5 O O 1 1 O O 5
4 O O 2 2 O O 4
3 O 3 O
1. WE: red connector is working electrode
2. AGND: green connector is ground
3. RE shield: (not connected in default plug)
4. CE: black connector or counter electrode
5. RE: blue connector or reference electrode
IMPORTANT:
The shield of the cable must make contact with the metal case of the sensors connector.
Files
All files are ASCII and can easily be read by other programs or text editors.
By default, the files are stored in the directory:
PalmSensPC\datafiles
The programs and default method files are stored in:
PalmSensPC\
File extensions
Scan techniques AD & PAD
Method files: .pms .pmt
Sample curve: .pss .pst
Analysis: .pds .pdt
RecordFile .psw .psw
The method file contains all specified parameters given in the Method parameter sheet and the Options menu.
The 'sample curve' (as well the 'analysis') files contains measured data of potential and current or time and current.
Default methods
Every time the program is closed, the method history list is stored. When the program is started again, most recently stored procedure is activated.
When the program is started for the first time, PSDiffPulse is loaded.
Battery maintenance
In case the battery capacity decreases it is adviced to switch on PalmSens and wait until it switches off automatically. After charging the batteries, their capacity might be restored again.
Warning: Do not charge the batteries when the ambient temperature is below 0ºC or above 40ºC. Charging is done most efficiently in the range of 10ºC to 30ºC.
Do not store the instrument with batteries in places where the ambient temperature is below 0ºC or above 40ºC.
Do not connect the charger with reversed polarity.
In case the batteries have to be exchanged follow the next steps.
Switch off PalmSens and remove all cables.
Remove the screws at the right-hand side of PalmSens using a proper screwdriver. Gently take out the batteries, unplug the connector. Connect the new batterypack and place the pack back in the instrument and tighten the screws again. Do not use any force.
Note: the batterypack must be obtained from Palm Instruments. Orderingcode: PS-NiMH-01.
Updating PalmSens firmware
The requirements are:
- CD-ROM or update from www.palmsens.com/update
- Serial download cable (standard null modem cable) to connect PalmSens to PC
Plug a serial cable in the connector of the PC as well as PalmSens.
Connect the batterycharger.
Switch on PalmSens and wait until the display shows 'PalmSens ready'.
Insert the update CD-ROM or put the disk in drive A: and Select Run after clicking on Start on the lower left corner of the PC display. Follow the next steps:
- Browse to CD-ROM or Diskette A:, select 'Download.exe' and run this program.
- The display of the PalmSens device shows: 'Press simultaneously the < > ESC and Enter keys'. As soon as these keys have been pressed the program on the PC says that the new software is downloaded. Please note that the PalmSens display is not changed when the four keys are pressed.
- Important: Do not press the four keys '< > ESC and Enter' during the time that the PC says that it is downloading the new software!
- The updated program is executed immediately.
IMPORTANT:
After updating the firmware, PalmSens has to be re-calibrated. Connect the PC and run the PalmSensPC program. Select the Control tab, and press the 'Calibrate offset'- button.
CH8 eight channel multiplexer
The multiplexer CH8 is used with PalmSens if a sensor-array is used. The presence of the multiplexer is specified from the mainmenu: Options/Options/Hwconfig. The channel is selected on the 'Control' parameter tabsheet.
CH8 is connected to the sensor connector of PalmSens. The miniDIN cable has to be connected to the connector at the left-hand side of the instrument. This miniDIN cable is used to power the multiplexer and to control the channel-selection.
In case the multiplexer is controlled from user-made software, refer to the example controlprogram, called 'PSControl'.
The multiplexer can be used in different modes. Each mode is set by a number of jumpers. On the board of the instrument there are seven jumpers marked by J1 … J7.
The jumpers are:
J1: Is placed when the sensor has a combined reference and counter electrode.
This jumper connects therefore RE to CE.
J2: If the sensorarray has more than one working electrode, but one counter and/or reference electrode, this jumper is placed. CE from PalmSens is connected directly to pin 1 and pin 19 of the 36-pin connector
J3: If the sensorarray has more than one working electrode, but one counter and/or reference, this jumper is placed. RE from PalmSens is connected directly to pin 7 and pin 25 of the 36-pin connector
J4: This jumper is placed if CE has to be multiplexed. This is the case when each of the sensors has its own counter electrode.
J5: This jumper is placed if RE has to be multiplexed. This is the case when each of the sensors has its own reference electrode.
J6: Is placed if all unselected working electrodes or sensors have to remain polarized at the potential as set by PalmSens. If this jumper is not placed only the selected channel is polarized. This option is not available in all devices. This jumper is effective only if IC13 and IC14, next to the jumper are placed.)
J7: For future use. Is left open normally.
The pins of the high density centronics connector on the CH8 module are:
Pin 1 CE when J2 is placed. Pin 19 CE when J2 is placed.
Pin 2 CE channel 1 Pin 20 CE channel 2
Pin 3 CE channel 3 Pin 21 CE channel 4
Pin 4 CE channel 5 Pin 22 CE channel 6
Pin 5 CE channel 7 Pin 23 CE channel 8
Pin 6 Ground Pin 24 Ground
Pin 7 RE when J3 is placed. Pin 25 RE when J3 is placed.
Pin 8 RE channel 1 Pin 26 RE channel 2
Pin 9 RE channel 2 Pin 27 RE channel 4
Pin 10 RE channel 3 Pin 28 RE channel 6
Pin 11 RE channel 4 Pin 29 RE channel 8
Pin 12 Ground Pin 30 Ground
Pin 13 Ground Pin 31 Ground
Pin 14 WE channel 1 Pin 32 WE channel 2
Pin 15 WE channel 2 Pin 33 WE channel 4
Pin 16 WE channel 3 Pin 34 WE channel 6
Pin 17 WE channel 4 Pin 35 WE channel 8
Pin 18 Ground Pin 36 Ground
Location of the pins:
Pin1 right upper Pin 19 right lower
Pin 18 left upper Pin 36 left lower
CH8 cable
Pin assignment of the CH8 high density plug of the cable:
1 upper left 18 upper right
19 lower left 36 lower right
Color codes
Brown 1 CE Direct
Brown white 19 CE Direct
Red 2 CE1
Red black 20 CE2
Orange 3 CE3
Orange black 21 CE4
Pink 4 CE5
Pink black 22 CE6
Pink red 5 CE7
Pink blue 23 CE8
White 6 GND
White black 24 GND
Yellow 7 RE Direct
Yellow black 25 RE Direct
Green 8 RE1
Green black 26 RE2
Dark blue 9 RE3
Dark blue white 27 RE4
Purple 10 RE5
Purple white 28 RE6
Grey 11 RE7
Grey black 29 RE8
Grey yellow 12 GND
Grey green 30 GND
Salmon pink 13 GND
White pink 31 GND
White yellow 14 WE1
White green 32 WE2
Green red 15 WE3
Green blue 33 WE4
Light blue 16 WE5
Light blue black 34 WE6
Light blue red 17 WE7
Light blue dark blue 35 WE8
Blue yellow 18 GND
Blue green 36 GND
Specifications
Number of channels 8
On resistance WE and RE channels: 85 ohm typical
CE channel 900 ohm typical
Leakage current 10 pA typical at 25 ºC
100 pA typical at 25 ºC
Charge injection -0.5 pC typical
Trouble shooting
1. In case the display of PC shows PalmSens not connected, follow the next steps:
• Check whether the > and < are shown consecutively on line 1 of the PalmSens LCD. If this not not shown reset PalmSens by pressing >< ENTER ESC (four keys) simultaneously.
• Check the 9 pins D-connector at the lefthand side of PalmSens
• Check the USB connector of the PC.
2. In case PalmSens can not be switched on.
• Check the adapter by measuring the voltage across pin 1 and the case of the mini-DINconnector. The reading must be at least 6 V. If this is not correct try another 6 V adapter (please note the polarity).
• Change the NiMH batteries
• Reset PalmSens by pressing <> ENTER ESC (four keys) simultaneously.
3. In case the pc cannot find the USB driver software, after connecting the USB cable.
• If the PalmSensPC software has not been installed yet, insert the Installation CD, and use the browse button to point to the CDROM folder: "iviumusbdrivers".
• If the PalmSensPC software has already been installed, but the driver for some reason was removed, use the browse button to point to the "PalmSensPC/iviumusbdrivers" folder.
4. In case the PalmSensPC program cannot find an (or all) available PalmSens Instruments:
• Check whether all USB cables have been properly plugged in.
• If the program already established a connection, it must be disconnect before it can show other devices.
• If the new device has been "freshly" plugged in, the refreshment of the list may need to be triggered. Simply give another program temporary the focus, PalmSensPC will refresh the list after regaining focus.
• When running multiple instances of PalmSensPC, note that each application can only connect to a single instrument. When a device has been connected, that specific instrument will not show up in the list of available instruments of the other PalmSensPC applications.
• If you are using a new interface cable in combination with an older version of the PalmSensPC program, you will need to update the software.
5. In case the USB cable is connecting without a problem but the PalmSensPC program cannot find any PalmSens Instrument:
• Goto the Windows Device Manager (Control Panel/System).
• Find the entry Universal Serial Bus Controllers, and select "Ivium USB device", and choose "update driver".
• Browse manually to the path of the driver: /PalmSensPC/iviumusbdrivers or /iviumusbdrivers on the installation CDROM.
Contact the supplier of the instrument if the problems remain and send the information.
Special multiplexer adaptation
Release notes special multiplexer adaptation
You can activate the special multiplexer adaptation, by inserting the activation code in the PalmSensPC software: Select Options/Options form the Main Menu, and choose the "Hwconfig" tabsheet. Type the code in the Special Config field, and close the dialog. When a timescan method is selected, a new tabsheet appears in the left panel, named : "Mux".
On the Mux tabsheet several controls appear:
Filename edit box: to indicate the filename where the results will be stored automatically.
Checkbox to indicate 8/16 channel operation, 8 by default.
Checkbox to avoid dataloss, a numerical value will be added to the filename when a datafile with the same name already exists.
Checklistbox to indicate which channels should be measured.
An "repetitions" control to indicate the number of cycles to execute.
A <start project> button to start a project. Please note that the "normal" <start> button, on the down right panel, initiates just a single scan.
An <abort project> button to abort the ongoing project, after finishing the current scan. Please note that the "normal" <abort> button, on the down right panel, stops just the single ongoing scan.
A <load project> button to recall and plot previously recorded projects. Note that all cycles will be plotted, while only a single cycle is visible during the measurement.
On the file format of the Mux files:
Extension ".psu".
ASCII format with columns separated by spaces.
1st row = Sample name
2nd row = Sensor name
3rd row = Number of channels : 8/16
4th to 11th row = content of Measure boxes: 0/1 ( 4th to 19th row for 16 channels)
next rows are filled with datapairs: 2*8 columns for 8ch, 2*16 columns for 16ch, all time values are defined with respect to the start time of the project.
Non-measured channels will still appear in the file filled with 0, except when these represent the last column(s). In the latter case, such columns will not appear in the result file.
Tips:
Use the 3D option on the result sheet to get a clearer separation of the results from different channels. The 3rd axis will indicate the channel number.
You can use the "Data result" sheet to view the numerical values of the result and export them to Excel: <Load project>, press <Meas result> on the "Data result" sheet, and copy the content to the clipboard with the <copy grid/selected cells> buttons. Now you can paste the data in any Windows application such as Excel.
Use the "Visible Scan" Checkboxes in the Legends panel, to hide specific channels.
Press F1 to get help.
Notes:
The <Delete> scan button at the Legends panel is disabled when the Mux is activated. After it use, the "scan number = channel number" relation would be lost.