Time-Controlled DC-Measurements Controller program for the pre-treatment of probes Data aquisition software for electrochemical applications Time controlled potentiostatic & galvanostatic methods © Zahner 11/2008 PVI -2- PVI -3- 1. General ___________________________________ 6 2. Start of PVI ________________________________ 8 2.1 The Main Menu ________________________________________________ 8 2.2 The Submenus ________________________________________________ 9 2.2.1 Define Setpoints____________________________________________ 2.2.2 System Parameter __________________________________________ 2.2.3 Execute ___________________________________________________ 2.2.4 Evaluation_________________________________________________ 2.2.5 Setup IM6 _________________________________________________ 2.2.6 CONCAP __________________________________________________ 9 9 9 9 9 9 3. The PVI Editor - < Define Setpoints > _________ 10 3.1 Splitting the Memory Into Partitions - < MEMORY > _________________ 10 3.1.1 Reserve Memory for Setpoint List - < SPts > ___________________ 11 3.1.2 Reserve Memory for 'Internal' Measure Points (E,I,t) - < MPts > ____ 11 3.1.3 Reserve Memory for 'External' Measure Points - < APts > ________ 11 3.2 Define Input Window - < Range & Resolution > ____________________ 11 3.2.1 Define Time Resolution - < Time Resolution > _________________ 3.2.2 Select Potential Range - < E-Range > _________________________ 3.2.3 Select Current Range - < I-Range > ___________________________ 3.2.4 Select Vertical Resolution - < Y-Zoom > _______________________ 12 12 12 13 3.3 Setup Potentiostat ____________________________________________ 13 3.3.1 Select Active/Inactive Potentiostat - < POTstate > _______________ 3.3.2 Select Operating Mode of Potentiostat - < POTmode > ___________ 3.3.3 Select Autoshunt or Fixshunt Mode - < I-Range > _______________ 3.3.4 Select (E,I,t)-Data Acquisition - < DataAcqu > __________________ 13 13 14 14 3.4 Editing a PVI Control Sequence _________________________________ 14 3.4.1 Add Corner Point(s) - < APPEND > ___________________________ 3.4.2 Numerical Input - < ? > _____________________________________ 3.4.3 Change Mode of Operation - < Change Mode > _________________ 3.4.4 Edit Corner Point(s) - < EDIT > _______________________________ 3.4.5 Delete Existing Corner Point(s) - < DELETE > __________________ 14 15 16 16 17 3.5 Clear PVI Control Memory - < CLEAR C-DATA >____________________ 17 3.6 Setup Data Acquisition (Optional ANDI-Amplifier Modules) __________ 17 3.6.1 Select Active Channels _____________________________________ 17 3.6.2 Activate Data Acquisition ___________________________________ 18 3.6.3 Define Sampling Frequency _________________________________ 18 PVI -4- 3.7 Modify I/O’s __________________________________________________ 19 3.7.1 Signal Acquisition Setup____________________________________ 20 3.7.2 Save & Load Calibration Factors _____________________________ 21 3.7.3 Check Active Inputs________________________________________ 21 4. Saving & Loading of Control Data ____________ 22 4.1 Load File - < OPEN > __________________________________________ 22 4.2 Save File - < SAVE >___________________________________________ 22 4.3 Creating Repetitive Curves - < SEQUENCES > _____________________ 22 5. System Parameter _________________________ 23 5.1 Reentry to EIS-Program ________________________________________ 23 5.2 Shunt Resistor and Current Range & Limit ________________________ 23 5.3 Current Limit - < LATENCY TIME > _______________________________ 24 5.3.1 Defining an Active Control Window t>0 _______________________ 24 5.3.2 Selection of Immediate Interrupt t=0__________________________ 24 5.3.3 Switching Off Software Current Control t<0 ___________________ 24 5.4 Settling Time _________________________________________________ 25 6. Execute – Select Online Display and Start Measurement ____________________________ 26 6.1 Selection of Online Display - < SELECT DISPLAY > _________________ 27 6.1.1 'Single'-Scope Display______________________________________ 6.1.2 'Double1'-Scope Display ____________________________________ 6.1.3 'Double2'-Scope Display ____________________________________ 6.1.4 'Triple'-Scope Display ______________________________________ 27 28 28 29 6.2 Select Input of an Axis - < SELINP >______________________________ 29 6.3 Scaling of Data - < SELGAIN > __________________________________ 30 6.4 Select Window Refresh Time - < SELTIME > _______________________ 30 6.5 Start Measurement - < START MEASUREMENT >___________________ 31 6.6 Stop Measurement - < STOP MEASUREMENT > ____________________ 31 7. Evaluation – Visual Display of the Data _______ 32 7.1 Select Active Channels - < E Chann > , < I Chann > _________________ 32 7.2 Select Scale Type - < E Scale > , < I Scale > _______________________ 33 7.3 Redraw Graphs - < E Redraw > , < I Redraw > ______________________ 33 7.4 Setting of Cursors - < Cursor1 > , < Cursor2 > _____________________ 33 7.5 Magnification of Window - < Zoom > _____________________________ 33 PVI -5- 7.6 Display Whole Measurement - < Total >___________________________ 33 7.7 X/Y-Presentation of the Measuring Data - < XY-plot > _______________ 33 7.8 Select X-Y-Channel - < X Chann > , < Y Chann >____________________ 34 7.9 Select X-Y-Scales - < X Scale > , < Y Scale > _______________________ 34 7.10 Redraw X-Y-Diagram - < XY Redraw > ___________________________ 34 7.11 Return to Time-Representation - < EI-T-Plot >_____________________ 34 7.12 Calculating Integrals ∫E(t)dt / ∫I(t)dt______________________________ 34 7.13 Integration with Baseline ______________________________________ 35 7.14 Printer Hardcopy - < HARDCOPY > _____________________________ 35 7.15 Create ASCII-Data List - < DATA LIST > __________________________ 36 7.15.1 Listing PVI (E,I,t)-Data _____________________________________ 7.15.2 Listing ACQ-Data _________________________________________ 7.15.3 Control Parameters of ASCII-List Output _____________________ 7.15.4 Output of ASCII-List_______________________________________ 36 37 37 38 7.16 Saving & Loading of Measurement Data - < DiskOps M Data > _______ 38 7.16.1 'load file' - < OPEN > ______________________________________ 38 7.16.2 'save file' - < SAVE > ______________________________________ 38 7.17 Evaluation of Other Time Data _________________________________ 39 PVI -6- 1. General The PVI program has been developed to fill holes in the already existing EIS software. The programs at disposal allow the user to record cyclic voltammograms (CV) or steady voltage-current curves (I/E). CE makes it possible to record general parameter-impedance curves which can be analyzed by means of various reports, for example, capacity reports or ac polarography. The EIS program, which is related to impedance spectroscopy, allows to carry out impedance measurements within a wide frequency range at a given but steady potential or current. Although there is a variety of different measurement programs, however, not all possible measuring parameters can be selected arbitrarily at the same time. The PVI completes the existing software package and enables the user to carry out measurements in the time domain. Different control and measuring sequences can be aligned in equal intervals. The PVI offers an almost infinite number of measurement possibilities due to the various modes of the potentiostat, which can be selected freely. A sequence of PVI elements is created by an integrated graphic editor. In the following, PVI elements should be defined as individual ramps, which have been fixed by the corner points <tn,En/In> and <tn+1,En+1/In+1> respectively. Any setting of recording and output parameters is available. These are the possible operating modes of the potentiostat: Mode of operation: potentiostatic galvanostatic Measuring range: fixes shunt in potentiostatic mode auto shunt in galvanostatic mode Data acquisition: Sampling rate: on/off 1mHz <= fsamp <= fmax The maximum sampling frequency fmax is dependent on the selected operational mode and the cpu unit in use. Each ramp starts at a certain default data doublet < time tm, potential Em or current Im > and ends at the next element < tm+1,Em+1/Im+1 > . The starting point of the new element is equivalent to the terminating point of the preceding element. The editor continuously displays the operating parameters time and potential/current as well as the slew rate of voltage or current. During the data acquisition, all operating parameters of the potentiostat are acquired and stored as data triplets <t,E,I> (time, potential, current), with the measurement of the parameters potential and current being integrable. The sampling rate which has been determined for the active PVI element is applied. The impedance measurement system averages ten measuring points continuously. These internal measuring points are sampled by means of the repetition rate of the output data. The refresh rate of the output parameters is between 1kHz and 10kHz and is again dependent on the CPU performance as well as on the operating mode of the potentiostat. PVI -7- The maximum usable time domain for a PVI element is 500h, with the mini mum resolution time being dt=1ms. PVI allows to study - steady states (dE/dt=0 or dI/dt=0), - slow changes in states (dE/dt ≈ mV/min) and - tests with fast pulses (dE/dt ≈ kV/sec). The measured parameters are shown online in the time window active at this moment. The time window is described by the default data during each measurement. The user is able to observe the operating conditions and if need be, he could intervene into the measurement, thus excluding the loss of data determined by then. The PVI offers different graphic presentations for the data report. The measuring data is either represented linearly or logarithmically as E(t) or I(t) plots. A X/Y-representation of the current data against the potential data is included. User-defined reports, however, are integrable, too. PVI -8- 2. Start of PVI PVI belongs to the group of measuring programs named <Time Domain>. To start PVI activate the icon named time domain and a further menu will pop up. Consequently select the icon named <PVI> and confirm. Now PVI will be started. 2.1 The Main Menu PVI starts up with a graphical logo including a set of buttons that may be activated by the user. Within PVI each of the buttons represents a submenu or an i/o-function. PVI -9- 2.2 The Submenus The submenus may easily be recognized by their titles and symbols being plotted within the button. The main menu manages the following submenus, which will briefly be described. 2.2.1 Define Setpoints - Line editor to define setpoint list - Selection of mode of operation - Setup of additional data acquisition 2.2.2 System Parameter - Setting of software controlled current limiting - Bandwidth limiting of potentiostat - Reentry function to impedance program 2.2.3 Execute - Selection of on-line display - Selection of on-line data - Scaling of on-line data - Start of measurement 2.2.4 Evaluation - graphical display of measure data - disc i/o operations of measure data - various displays - output to ASCII formatted list 2.2.5 Setup Zennium - control potentiostat via test sampling of impedance measurement program 2.2.6 CONCAP - pi-controller to measure C(E)-curves PVI - 10 - 3. The PVI Editor - < Define Setpoints > The editor input page consists of different regions of interest. Each of the regions represents a submenu. Parameter and data of interest are shown within reserved output boxes. The input window is displayed in the middle of the screen. The input window is scaled to default settings after the start. Starting at t = 0 sec, the time axis runs from the left to the right. The scales of potential and current values run on the vertical axis. 3.1 Splitting the Memory Into Partitions - < MEMORY > Depending on the demands of the control sequence the memory being reserved by the PVI-program may be split into three partitions of different size. The memory being available for the PVI-program itself depends on the memory partitioning of the operating system and may be altered by use of the utility program 'konfigur'. Considering the different demands of PVI-control sequences partitioning of the memory by the user will become obvious. Steady state experiments at a fixed potential Eset or at a constant current Iset will require a low number of setpoints and will offer nearly all memory for data acquisition. Repetitive execution of puls sequences, however, will demand a high number of setpoints and will reduce the memory being available for data acquisition. Running internal and external data acquisition in parallel the memory for both types of data may be defined individually depending on the sampling frequencies fint & fext and on the number of active channels n. PVI - 11 - The three partitions of memory will be set by use of sliding controllers. The upper and the lower limit will be set in concurrence with the actual fractions and free memory. The total memory being available will be denoted within the output boxes named <MEMORY>. The individual memory partitions of setpoints <SPts>, measure points <MPts> and data acquisition points <APts> will be denoted both in units of percent of the total memory and in units of data points. The reserved memory will be denoted in units of kByte right to the corresponding slider. 3.1.1 Reserve Memory for Setpoint List - < SPts > Activate the controller named <setpoints> and move the slider either by moving the mouse or by using the cursor keys <<> and <>>. The upper limit will be set automatically with respect to the setting of <MPts> and <APts>. The lower limit will be defined by the actual number of setpoints being used. Using the HOME-function will reset the measure point memory to the initial value. Choose the new memory and use the ENTER-function to confirm the new setting. 3.1.2 Reserve Memory for 'Internal' Measure Points (E,I,t) - < MPts > Activate the controller named <measure points> and move the slider either by moving the mouse or by using the cursor keys <<> and <>>. The upper limit will be set automatically with respect to the setting of <SPts> and <APts>. The lower limit will be defined by the actual number of measure points being used. Using the HOME-function will reset the measure point memory to the initial value. Choose the new memory and use the ENTER-function to confirm the new setting. 3.1.3 Reserve Memory for 'External' Measure Points - < APts > Activate the controller named <data acquisition> and move the slider either by moving the mouse or by using the cursor keys <<> and <>>. The upper limit will be set automatically with respect to the setting of <SPts> and <MPts>. The lower limit is equal to zero. Selecting no memory at all will disable the data acquisition of additional amplifier modules. Using the HOME-function will reset the memory of data acquisition to the initial value. Choose the new memory and confirm by using the ENTERfunction. 3.2 Define Input Window - < Range & Resolution > Depending on the time resolution of the element to be put in ( e.g. steady state experiments at Econst/Iconst or recording of fast pulse response signals ) different time scaling has been prepared. The input range of potential Ecntrl or current Icntrl of the controlling function may be adapted to the individual demands. By the fine scaling option <Y-Zoom> the vertical resolution may be increased by a factor of 5 or 25. Using Y-Zoom will split the vertical axis and increase the vertical sensitivity for input. PVI - 12 - 3.2.1 Define Time Resolution - < Time Resolution > Each time page will consist of 500 steps in horizontal resolution. The actual time resolution will be marked by a green square right to the selective button of the menu list. To choose a different time resolution activate the corresponding button and confirm the selection. The time resolution is defined by the interdependent parameters 'window width' and 'mouse sense'. Both parameters have been listed on top of the selective buttons. The chosen mouse sensitivity will be put out additionally within the output box named <X-Res> in the parameter section of the main menu of the graphic editor. 3.2.2 Select Potential Range - < E-Range > The active potential resolution is marked by a green square right to the selective button of the menu list named 'E-Range'. To choose a different resolution activate the corresponding button and confirm the selection. Potential setting will be used to define the output range of a potentiostatic element and does not affect the resolution of the measured potential. The potential range must be selected in accordance to the used hardware. Using the internal potentiostat the output range is limited to a range of dE= ±4V. By use of the buffer amplifier the output range may be extended up to ±10V (±20V-Range ). The ±40, ±80V and ±120V options have been prepared for use with the compliance voltage booster CVB80 or CVB120 only. Each vertical page will consist of 320 steps in resolution being symmetrical to the middle of the page (offset during input). The potential re solution is defined by the interdependent parameters 'Y-Fac' and 'Y-Res'. Selecting an E-Range (Y-Fac) of ±4V will result in a mouse sensitivity (Y-Res) of 25mV of each mouse step (MS) (25mV/MS,Y-Zoom=1). Using the Y-Zoom option the vertical sensitivity may be increased by a factor of five (5mV/MS) or by a factor of twenty-five (1mV/MS) and will split the vertical axis. The parameters will be put out within the output boxes named <Y-Fac> and <Y-Res> in the parameter section at top of the main menu of the graphic editor. 3.2.3 Select Current Range - < I-Range > The selected current range will be marked by a green square right to the selective button of the menu list named 'I-Range'. To choose a different resolution activate the corresponding button and confirm the selection. <current range> must be used to define the output range of a galvanostatic element and does not affect the resolution of the measured current. The current range must be selected in accordance to the used hardware. Using the internal potentiostat the output range may be any one between ±400nA and ±4A. Note that the upper limit will be given by the maximum possible output current of the used potentiostat (±1A, ±2A or ±3A ). By use of HIZ-probe amplifiers the output range may be extended down to a ±4nA-Range. The ±40A and ±400A options have been prepared for use with the electronic loads EL100/EL101/EL300 only. PVI - 13 - Each vertical page will consist of ±160 steps in resolution being symmetrical to the middle of the page. The current resolution is defined by the interdependent parameters 'Y-Fac' and 'Y-Res'. Selecting an IRange (Y-Fac) of dI= ±40mA will result in a mouse sensitivity (Y-Res) of 250uA of each mouse step (MS) (250uA/MS,Y-Zoom=1). Using the Y-Zoom-option the ver tical sensitivity may be increased by a factor of five (50uA/ms) or by a factor of twenty-five (10uA/ms) and will split the vertical axis. The parameters will be put out within the output boxes named 'Y-Fac' and 'Y-Res' in the parameter section at top of the main menu of the graphic editor. 3.2.4 Select Vertical Resolution - < Y-Zoom > The vertical axis of potential and current will be scaled in ±160 steps of graphical resolution. Each increment or decrement will correspond to one mouse step. Using a vertical resolution Yres=1 will result in a mouse sensitivity of Rangeset/160 per mouse step and the total input range will be displayed within one screen. Selecting a higher Y-Zoom-value will increase both, the mouse sensitivity and the number of vertical pages. E.g.: Mode: Potentiostat Y-Zoom Sense 1 25mV/ms 5 5mV/ms 25 1mV/ms E-Range: 4V Pages & Range Offset E0 1 4.00V 0V 9 0.80V -ix0.80V,...,0V,...,+ix0.80V 49 0.16V -ix0.16V,...,0V,...,+ix0.16V i= 4 i=24 After startup the Y-Zoom-factor will be set equal to one by default. To choose a higher/lower Yresolution activate the corresponding button of the Y-Zoom menu list and confirm your selection. When using a high resolution mode (Yzoom=5 or Yzoom=25) the different pages will be accessible by and . The position of the actual page within the full input range will be use of the buttons displayed within the scale right to the input window. 3.3 Setup Potentiostat The potentiostat may be set up differently for each element of a PVI-control sequence. Note: changing the mode of operation does not affect the actual state of the potentiostat but will define the mode of operation of the next element(s) to be put in. During the execution the potentiostat's mode of operation will be set according to the individual preset(s). 3.3.1 Select Active/Inactive Potentiostat - < POTstate > <POTstate> works like a toggle switch and offers two states 'ON' active state to switch on potentiostat/galvanostat Select 'ON' to put out a control potential or to put out a control current. 'OFF' passive state to switch off potentiostat/galvanostat Select 'OFF' to switch off the potentiostat and record the rest potential. 3.3.2 Select Operating Mode of Potentiostat - < POTmode > <POTmode> works like a toggle switch and offers two states 'POT' potentiostatic mode PVI - 14 - Select potentiostatic mode 'POT' and switch 'ON' the potentiostat to perform e.g. voltammograms, potentiostatic polarization or potentiostatic pulse sequences. Select potentiostatic mode 'POT' and switch 'OFF' the potentiostat to record the rest potential. 'GAL' galvanostatic mode Select galvanostatic mode 'GAL' and switch 'ON' the potentiostat to execute constant current experiments like charging at a fixed current. 3.3.3 Select Autoshunt or Fixshunt Mode - < I-Range > This toggle switch will shift between 'LIN' 'LOG' linear measurement of current (solid laboratory resistor) logarithmic measurement of current (auto-shunt) depending on the program version. 3.3.4 Select (E,I,t)-Data Acquisition - < DataAcqu > Data acquisition may be selected differently for each PVI element. The memory being available for data acquisition may thus be splitted to different regions of interest by the user, e.g. slow ramps will be monitored with a low acquisition rate and fast pulses will be measured with a high sampling frequency. Further on elements may be put in where no data will be measured at all. To select a certain sampling frequency activate <DataAcqu> and select the corresponding button or switch off the data acquisition if desired. The set sampling frequency will be marked by a green filled rectangle right to the corresponding button. 3.4 Editing a PVI Control Sequence 3.4.1 Add Corner Point(s) - < APPEND > Clicking this menu point allows either to enter a new curve or to append further points to an existing curve. The program's input mode is active as soon as APPEND has been selected. A new ramp can be defined when starting at zero or at the element entered last. During editing, the following parameters are displayed in the parameter field: a) b) c) the absolute default data tabs, Uabs or Iabs at the current cursor position, the relative changes of these parameters in relation to the PVI element entered last, the slew rate of voltage or current, which is shown as a third parameter, results from the relative values. The new PVI element can be entered by confirming when the new terminating point has been reached. Several aspects may lead to the input of a new element. Corner points may already be defined or the desired slew rate can be realized for a certain time span tsoll. The input of the required values can comprise times or potentials which are outside the window currently displayed. As soon as the mouse is moved over the left, right, upper or lower limit of the PVI - 15 - window, a shift to a new window is effected automatically. During the input of a line element the mouse sensitivity may be altered by use of the toggle function (right mouse key). 3.4.2 Numerical Input - < ? > Corner points may be defined by a direct input routine too. To put in or to add a new corner point activate the <append>-function and use the <?>-key to call the input routine. The input box offers the input of the following parameters - Ea/Ia dt Ee/Ie S the starting potential/current the runtime of the element the ending potential/current the potential/current slope A new element will be defined by use of three parameters - Ea, Ea, Ea, dt, dt, Ee Ee, slope slope The remaining parameter must be declared unused by clearing the corresponding input line with the <crol>-key (clear rest of line). Otherwise the input will be over determined and the input routine will prompt an error message. The starting potential or the starting current will be put in absolute units of Volts or Amperes. As starting point the input routine will suggest the last potential/current having been put in. The runtime of the new element must be put in in units of seconds. Finally the ending potential or current will be defined. This input may be an absolute value PVI Ee/V : 2V(abs) - 16 - En=2V or a step relative to the last corner point's potential or current Ee/V : 1V(rel) En=En-1+1V Another way to put in a new ramp is to define its runtime and potential slope or current slope. 3.4.3 Change Mode of Operation - < Change Mode > The operating mode of individual PVI elements can be changed additionally after the input. Set the desired operating mode and change the relevant elements. To select an element move the crosshair close to the line element to be changed and confirm the selection. The program then will search for elements which are within the region of the crosshair in a defined capture range. After an element has been identified it will be included into the editing mode and will be marked by flashing the corresponding line. The updated operating parameters are again displayed online in the information field. Use the ENTER function to change the mode or use the ESCAPE function to leave that element unchanged. The ESCAPE function finally is used to leave the editing mode. 3.4.4 Edit Corner Point(s) - < EDIT > After the input of the control elements via <append> or after an existing control curve has been loaded PVI offers the possibility to edit the corner points. Thus fine corrections of a control curve may be done. 126.96.36.199 Moving Corner Point(s) To edit a corner point move the crosshair close to the corner point to be changed and confirm the selection by use of the ENTER function. The program searches for corner points which are within the region of the cross hair in a defined capture range. After a corner point has been identified it will be marked by the flashing cursor. Confirming this measuring point includes it in the editing mode. As described under <append> the measuring point can now be entered newly. The updated operating parameters are again displayed online in the information field. The parameter time can only be varied in a region which is stretched out by means of Pm-1 and Pm+1 in order to avoid erroneous input. The ESCAPE function is used to leave the editing mode. 188.8.131.52 Insert New Intermediate Point(s) To insert a new corner point between two existing PVI elements, move the crosshair close to the line which is localized by these points. When the computer has identified one of the lines within its capture range, a new corner point is defined and can be edited as described above. 184.108.40.206 Possible Error With <EDIT> a) b) The crosshair has not been moved close enough to the element sought after. In this case, the computer draws the attention to the user with the help of an audible signal. Too many points or lines have been identified. In this case, an error message is given and one is asked to select a finer time resolution or to specify the point which should be edited newly. PVI - 17 - 3.4.5 Delete Existing Corner Point(s) - < DELETE > This function is used to delete corner points of an existing PVI list. To delete a corner point move the crosshair close to that corner point and confirm the selection by use of the ENTER function. The program searches for corner points which are within the region of the crosshair in a defined capture range. After a corner point has been identified it will be marked by the flashing cursor. The selected point is deleted by confirming with the ENTER function. To cancel the delete function use the ESCAPE function. Errors are recognized and displayed as being described above. 3.5 Clear PVI Control Memory - < CLEAR C-DATA > This option will be used to clear the memory of the control data section. An existing curve will be cleared and the control curve editor will be reset to the initial settings. Erroneous use will be prevented by an input box Confirm to clear all control data or escape to leave all inputs unchanged. 3.6 Setup Data Acquisition (Optional ANDI-Amplifier Modules) In addition to the potentiostat which will deliver the measure data of potential E and current I supplementary amplifier modules may be installed. These modules will list additional parameters of the experiment, like temperature, pressure, pH-value, viscosity, speed of rotation, etc. The data acquisition modules will be put into the system and the single input channel's parameter set will be defined via the function <Signal Acq.> and it's sub-function <Signal Acquisition Setup> . The signal acquisition setup may be called nearly from every measuring program of the Zennium. The input channels can be recalibrated and the sequence of active channels can be altered with respect to actual requirements. After return all parameters of the data acquisition setup will be passed to the calling program. 3.6.1 Select Active Channels The data acquisition setup can handle 32 input channels of additional acquisition modules. Data acquisition of analog channels with PVI, however, is restricted to a maximum of 10 active analog channels. Thus the desired channels must be within the ten first channels of the data acquisition setup. By an interactive exchange PVI will obtain the calibration parameters and the addresses of those channels. To check and setup the data acquisition activate the function <Setup Data Acquisition> by use of the button. Within the editor's page a submenu will pop up and offer selection of active channels. Activate all desired channels by use of the corresponding <Chan x> button. An active channel will be marked by a green square right to the button, an inactive channel will be marked red. PVI - 18 - 3.6.2 Activate Data Acquisition In contrast to the measurement of the PVI data triplets <E,I,t>, which will be measured with respect to the setting of the corresponding PVI element, analog data acquisition will run thru the whole measurement if data acquisition will be active. To switch off or on the data acquisition at all, use the button <ON> or <OFF> at the top left of the input list. Activated data acquisition will be marked by a green square and offer to switch <OFF> while inactive data acquisition will be marked red and offer to switch <ON> data acquisition. 3.6.3 Define Sampling Frequency Due to the structure of the operational system's measuring macro, all additional data channels must be sampled with one fixed sampling frequency. The maximum sampling frequency itself will be restricted by the memory being offered by the system. Variation of the free memory of <APts> is offered by splitting the PVI memory via the <MEMORY> menu. To choose a certain sampling frequency activate the button named <sampling frequency>. A further submenu will pop up and offer a set of frequencies being split in decades. Each decade will be split in units of 1,2 and 5. The selected sampling frequency will be marked by a green square right to the corresponding button. To use all memory being offered for additional data acquisition select the additional option <fit maximum frequency to memory>. The maximum sampling frequency will consequently be calculated PVI - 19 - with respect to the settings of <APts> -memory and the number of acquisition channels being activated. 3.7 Modify I/O’s To registrade additional magnitudes of an electrochemical experiment the measuring programs of the THALES software can manage up to 32 supplementary analog inputs. The measured parameters will be amplified and normalized by the ANDI amplifier modules offered by ZAHNER. The actually offered modules are listed in the table below. Considering electrochemical investigations the TEMP/U module has become a standard. This module has two temperature channels for Ni/CrNi-thermocouples and two voltage inputs. module' amplifier card module# 1 2 3 4 5 6 7 8 9 10 11 amplifier card FE40 4ch E / diff. inputs LMV 1ch I / program. charge amp. PAM 1ch E / program. E-amp. TEMP 4ch Temp / iso-amp Ni/CrNi TEMP/U 2ch Temp / 2ch E RTD 4ch Temp / iso-amp PT100 DMS 4ch iso-amp for strain gauge sensors UMUX 8ch diff / 16ch sing E-amp ISO_IN 4ch E / iso-amp FILTER 1ch filter amp FE42 4ch E / diff. inputs, var. gain The management of additional analog inputs will be done by the common routines of the <Data Acquisition> -section. This program will be reached either from the main menu of the THALES software or by special entries from the measuring programs. The active number of analog channels may differ from program to program. PVI THALES main EIS programm PVI - 20 - 3.7.1 Signal Acquisition Setup To define or to modify an analog input channel activate the button <edit input>. Then move to either the left or to the right table. Each table can store the parameters of 16 input channels. Select the desired channel by moving the mouse arrow into the corresponding line. An activated input will be marked by a lit bar. To define/modify that channel's parameters call the editor by using the <ENTER> -function. Consequently an input function will offer the input of 15 parameters to calibrate and describe that input channel. An analog input channel must be defined by input of the following parameters - hardware address channel # module # : : digital address type of amplifier - descriptor and unit of measured magnitude magnitude unit max. display : : : physical/chemical magnitude unit to be put out maximum range of display - polynomial of calibration The digital data being read from the ADC will be converted to the physical value of the measured magnitude by use of a polynomial n PO M C0 C1 ADC n 2 C n ADC n e.g. polynomial to calculate the temperature T from the measured potential of a Cr/NiCr thermo couple (TEMP/U-module) PO C0 C1 C2 C3 C4 C5 polynomial order offset #0 gain #1 coefficient #2 coefficient #3 coefficient #4 coefficient #5 : : : : : : : 7 3.97085242e-3 0.101499149 -6.87552777e-6 3.86680650e-9 -1.64198803e-12 1.30383059e-15 PVI C6 C7 C8 coefficient #6 coefficient #7 coefficient #8 : : : - 21 - -5.10712536e-19 5.76442358e-23 0 To deactivate an analog input channel simply put in a zero as input channel number. Before confirmation check all inputs. To correct single parameters use the <CU> - <CD> -keys and move to the corresponding input line. To exit the parameter definition function confirm at the last input or exit by use of the <END> - or <ENDE> -key. 3.7.2 Save & Load Calibration Factors If an supplementary amplifier will be delivered with the system, the corresponding input channels will be defined by the manufacturer. Otherwise the calibration table will be delivered with the module and must be installed by use of the functions being described above. The calibration factors will be saved by using the saving option of the <global measurement preset>. Saving the complete parameter set will result in an automatic reinstallation after the next startup of the system. 3.7.3 Check Active Inputs The correct operation of the activated channels may be checked. Therefore the <signal acquisition> page must be entered. Up to a maximum of 10 activated channels will be displayed by the use of 'digital instruments' as shown above. By alternation of the input signal an control of the output signal all active channels can be checked. PVI - 22 - 4. Saving & Loading of Control Data The defined set of control data may be stored as a Control Data file or as a Sequence. Both types of control data may be loaded directly and offer an immediate start of the experiment. The functions which will be used to save and load control data are the same as being described in other parts of the THALES-manual. The buttons <Sequences> and <Control Data> lead to a submenu which will offer disc-i/o-operations. The following menu-points will be offered: 4.1 Load File - < OPEN > The selected control data file will be loaded to the editor. 4.2 Save File - < SAVE > Saves control actual control data to the selected subdirectory. 4.3 Creating Repetitive Curves - < SEQUENCES > Both kinds of data - control data and sequences - have the same internal format. Loading a control curve will erase the control curve being stored in the memory of the PVI editor. For the use of sequences, however, a special handler will be offered when sequences will be loaded to the editor: sequences will be appended to the actual control curve. A sequence describes a short(er) set of PVI-elements, e.g. a polarization at constant potential being followed by a short pulse. Sequences may be sets of potentiostatic or galvanostatic elements. By use of the <sequencer> those sequences may be arranged to a new curve of control data. Loading a sequence an input box will prompt, asking how often the selected sequence shall be appended to the existing control curve. Before a sequence will be loaded the system will check the editor's memory and will determine the maximum number that the selected sequence can be appended to the actual control curve. By the introduction of the sequence handler PVI offers a nearly indefinite degree of freedom to create control curves with respect to special demands. PVI - 23 - 5. System Parameter Within the installed measuring programs of the THALES system usually all settings of the potentiostat will be done by the software. To offer selective control of the hardware a set of system parameters has been provided. 5.1 Reentry to EIS-Program Some types of electrochemical investigations demand an EIS measurement directly after the probe has been prepared. After the EIS-spectrum a polarization shall follow and finally the sequences shall be terminated with a second EIS measurement. PVI therefore offers the automatic reentry to EIS. The experiment will be started with an impedance spectrum. Then the user changes to PVI and the DCsequence will be started. After the DC treatment has been finished, PVI will pass the last actual DCpotential of the potentiostat to the EIS program and a second impedance spectrum will be started automatically. 5.2 Shunt Resistor and Current Range & Limit Considering potentiostatic elements PVI will work with a fixed shunt resistor for the whole sequence. This shunt will be selected by the user either by determination or by estimation of the maximum DC current to flow. The following table may help to choose an adequate shunt resistor with respect to the expected DC-current that may flow. current / A 10 5 300 m 110 m 40 m 4m 400 u 40 u 4u 400 n 40 n 4n shunt / Ohm 10 m 100 m 1 10 100 1k 10 k 100 k 1M 10 M 100 M 1G note IM6 only Zennium/IM6 Zennium /IM6 Zennium /IM6 Zennium /IM6 Zennium /IM6 Zennium /IM6 Zennium /IM6 Zennium /IM6 Zennium /IM6 HIZ probe only HIZ probe only PVI - 24 - Selection of a specific current range will determine the used shunt resistor. The selection, however, will work semiautomatic. In the higher current ranges between 40mA and the maximum current lmax a fine splitting will be done automatically with respect to the maximum power consumption of the selected shunt. The potentiostat itself will be protected by a current limiting circuit with respect to the selected shunt resistor. The potentiostat otherwise will get no information about the allowed current through an electrochemical system. Thus the selection of a current range will define current limits that will be defined by the user and consequently will be controlled by the software. Current violations will cause an interrupt of a running PVI-sequence and the potentiostat will be disconnected from the investigated system. 5.3 Current Limit - < LATENCY TIME > Limiting the dynamic range of the DC-current offers protection of the system being connected to the potentiostat. Short current spikes caused by switching devices via 'electro smog', however, may cause an unwanted interrupt of the running PVI sequence. The parameter <latency time> has been prepared for selective control of current violations. ILimit enableinterrupt ILimit Potentiostat switched OFF t Trigger t+t latency CurrentI/arb.units CurrentI/arb.units PVI will continue stopPVI CurrentI/arb.units ILimit enableinterrupt CurrentI/arb.units stopPVI PVI interrupted ILimit t Trigger t+t latency 5.3.1 Defining an Active Control Window t>0 A current violation will trigger a time window. If the current will return to the allowed magnitude within the defined latency time (=window width) the measurement will continue. If the current will stay outside of the defined range the PVI sequence will be interrupted. 5.3.2 Selection of Immediate Interrupt t=0 Setting the current violation latency time equal zero will cause an immediate interrupt of the running sequences in case of current violations. 5.3.3 Switching Off Software Current Control t<0 Setting the latency time to a negative value will disable software current limiting at all. PVI - 25 - 5.4 Settling Time IMx potentiostats have been designed to work up to a maximum frequency of some MHz. This short response times may cause oscillation if the potentiostat will change its mode of operation or the current range will be switched. Especially switching the current range in galvanostatic experiments may cause unwanted spikes in the current signal. Considering DC-experiments the bandwidth of the potentiostat may be limited by a switch able low-pass in the potentiostat's feedback loop. The <settling time> may be set to the requirements of the planned experiment. <settling time> offers the following limits: settling time 100 ns 1 us 10 us 50 us 200 us edge frequency 10 MHz 1MHz 100 kHz 20 kHz 5 kHz Considering the internal sampling rate of the PVI driver of 10kHz, bandwidth limiting down to 50us will cause no loss of information. PVI - 26 - 6. Execute – Select Online Display and Start Measurement The actual measurement is started here. The input data are converted into internal control data of the machine. The conversion is indicated on the screen in a so-called 'busy' box. A time system guarantees the synchronous sequence of the actual measuring program in the background and makes an online representation of the latest potential and current values possible by means of a specific data exchange between the driver program and the PVI. A new graphic is set up after a defined runtime. The measuring range is displayed quasicontinuous in the data window in a reasonable resolution. Both the mouse and the keyboard are permanently scanned during the measurement. If the ESCAPEfunction will be activated, the measurement will be interrupted at the latest position. The data triplets <t,U,I> measured by then remain in the storage medium and can thus be evaluated. With that, it is possible to intervene at any position of the measurement and change the system's parameters. PVI - 27 - 6.1 Selection of Online Display - < SELECT DISPLAY > PVI offers different displays for the online display of the measured data. The single scope mode will preferably be used if only potential- and current data of the PVI sequence shall be displayed online. The double scopes and the triple scope have been provided for the display of additionally measured analog data. To select a online display activate the button named <select display> and a selective menu will pop up. Select the desired display and leave the menu by use of the ESCAPE-function. The displays run along the same time axis being plotted at the bottom of the window. At the top numerical displays have been installed to put out the measured data of all activated channels in numbers. The data will be plotted along a floating time axis. After a defined duration a refresh of the window will occur and the time axis of the next interval will be plotted. In case of an overflow a clipping window will be activated and the displayed data will be limited to the upper or lower limit of the corresponding axis. For each scale individual scaling and color selection have been prepared. 6.1.1 'Single'-Scope Display The single scope display offers one window with two y-scales, one at the left and the other at the right of the window. Both scales may be defined individually. PVI - 28 - 6.1.2 'Double1'-Scope Display The 'double1'-scope display offers two 'scopes' of identical height. Each scope offers two y-scales, one at left and the other at the right of the window. All scales may be defined individually. 6.1.3 'Double2'-Scope Display The 'double2'-scope display offers two 'scopes' of different height. The data of most interest may be displayed with a higher resolution within the lower window. Additional monitoring data may be displayed in the upper window. Each scope offers two y-scales, one at left and the other at the right of the window. All scales may be defined individually. PVI - 29 - 6.1.4 'Triple'-Scope Display The 'triple'-scope display offers three 'scopes' of identical height. Each scope offers two y-scales, one at left and the other at the right of the window. All scales may be defined individually. 6.2 Select Input of an Axis - < SELINP > Each scale may be assigned to an analog input channel. Input channels are the internal data potential and current or additional analog input signals being measured by supplementary amplifier modules. To assign an input signal to an axis activate the corresponding button <SelInp> of that axis. A selective menu will offer that analog channels which had been activated for the next measurement. All active inputs will be represented by a button storing the corresponding channels descriptor. The active channel will be marked by a green square right to the button. To select another analog channel activate that channels button. To switch off an axis select option <SCALE OFF> at the top of the selective window. To distinguish graphs being plotted within one window the different channels can be plotted with different colors. To select a certain color activate that colors button. The selected color will be marked by a green square right of the button. The selection of a certain color will influence both the color of the graph and the color of the axis being plotted. PVI - 30 - 6.3 Scaling of Data - < SELGAIN > To select certain regions of interest different scaling of the activated axis has been provided. Each scale may be defined individually. The limes of the display must not correspond with the maximum range of the corresponding input channel. In case of zooming clipping of the corresponding window will be activated. To define an axis' scaling parameters activate the button <SelGain> of that axis. A selective menu will offer the setting of three gain switches <Fine-Gain>, <Gain> and <Range>. Via <Range> an engineering unit will be selected. <Gain> will select a certain decade of that unit and is scaled in units of 1,2 and 5. <FineGain> finally offers a zooming of ±4, ±2 or ±1. The parameter offset will determine the position of the zero line. The offset must be put in after the input function has been activated by use of the <Offset> button. Example: To select a display between -10mA and +30mA choose Range: 1m Gain: 20 Fine Gain: 1 Offset: 10m 6.4 Select Window Refresh Time - < SELTIME > A new graphic is set up after a defined time has run down. This option offers splitting of the whole runtime into smaller intervals of time. By the use of splitting a better resolution of the displayed data may be obtained. The refresh time may selected between 10sek and 30hours, depending on runtime and desired resolution of the online display. To change the refresh time activate the button <SelTime> below the x-axis and select an interval. PVI - 31 - 6.5 Start Measurement - < START MEASUREMENT > To start the next measurement activate the button <Start Measurement>. The input data will be converted into internal control data of the machine and graphical display data will be calculated. Both processes will be indicated by a busy box. Finally the <Start Measurement> - button will change to a <Stop Measurement> - button and execution will be started. 6.6 Stop Measurement - < STOP MEASUREMENT > To interrupt a running experiment use either the ESCAPE-function or activate the STOP-button at the top right of the display window. After a measurement has run out or has been interrupted the data measured by then remain in the storage medium and can thus be evaluated. With that, it is possible to intervene at any position of the measurement to change the default data or Imax. An immediate restart will be possible as the control data will be stored and accessible in memory. PVI - 32 - 7. Evaluation – Visual Display of the Data The software version of EVALUATION on hand contains subprograms for the graphic representation of data. After the selection, the measuring data, which are available in an internal reporting format by then, are transformed in real number triplets. This is required because the data are saved in a format (4 byte integer) other than the one applied for reporting (8 byte real). During the data conversion, this is indicated by an alert box. After the conversion has been finished, the program changes to another graphics page with a new set of buttons. The basic setup of the graphic shows the current and the voltage channel as two separate graphics over the acquired time range. Two cursors are strobed additionally, with CURSOR 1 being the starting point and CURSOR 2 being the terminating point. The latest cursor settings are again displayed in the upper data field. The following subprograms have been provided to cut out a curve by reverse clipping or to enlarge a window. 7.1 Select Active Channels - < E Chann > , < I Chann > These toggle functions allow to activate and deactivate the two measuring channels for the graphic presentation. If both channels are active, the re presentation will be done in two frames of equivalent height. The overall height of the screen will be used for graphic operations if only one channel has been activated. PVI - 33 - 7.2 Select Scale Type - < E Scale > , < I Scale > Both data channels can either be printed out linearly or logarithmically. One can choose between those ways of presentation by using the toggle functions I scale and U scale. In the logarithmic representation, negative Y-values have another color than the values of the positive Y-range. 7.3 Redraw Graphs - < E Redraw > , < I Redraw > Using one of these functions results in rebuilding the graphic. However, the execution will be denied if the relevant data channel has been deactivated 7.4 Setting of Cursors - < Cursor1 > , < Cursor2 > Cursor 1 and Cursor 2 are used to reset the cursors within the data range. The mouse arrow disappears and is connected to two cursor segments (vertical and horizontal axis). The arising crosshair can be scrolled to the left or to the right with the mouse, but the cursor follows single data points. The contents of the single measuring points are assigned to the relevant cursor and are displayed to the right of the upper screen region. Pressing RETURN/ENTER changes the position of the cursor. The ESCAPE function is used to exit the Cursor functions. The cursor returns to its original position. 7.5 Magnification of Window - < Zoom > Clicking this function prompts the program to adopt the latest cursor positions as new extrema of the time axis and to present spread measuring data in a redefined time window. Renewed setting of the cursor and sub- sequent confirmation of the Zoom function allows further magnifications. 7.6 Display Whole Measurement - < Total > It will be possible to restore the data of the whole time field by this function if the measuring data field has been zoomed. 7.7 X/Y-Presentation of the Measuring Data - < XY-plot > It is often advisable to use XY-plots in order to recognize the inter relations between the measurands time, potential and current. In this subprogram, the user is able to apply one measurand (t,U,I) to another measurand (t,U,I). Linear as well as logarithmic shifts are possible for both scales. That is why logarithmic I(t) plots and double logarithmic I(U) plots can be used like any other combinations. As in the linear presentation modes, the user is free to define the output parameters and their way of representation. PVI - 34 - 7.8 Select X-Y-Channel - < X Chann > , < Y Chann > The corresponding data channel can be selected via these functions. 7.9 Select X-Y-Scales - < X Scale > , < Y Scale > The corresponding scale can be selected here. The content of the other menu points, regarding the X/Y-presentation, is equivalent to the one of the linear representation modes. 7.10 Redraw X-Y-Diagram - < XY Redraw > The X-Y-graphic will be redrawn if any of the display parameters ( X-Chann, Y-Chann, XScale or Y-Scale) has been changed or the cursors have been set to another position within the data. 7.11 Return to Time-Representation - < EI-T-Plot > The display will return to the E(t)- and I(t)-representation of the data. The switch will only act if X-Y-representation had been activated. 7.12 Calculating Integrals ∫E(t)dt / ∫I(t)dt This function will work in the E-I-representation of the PVI-data only. By use of the cursors a time interval will be defined and finally the pro gram will calculate the desired integral. The result of the calculation will be put out at the top of the display. The following data will be listed: ∫abs ∫pos ∫neg ∫net mathematical overall integration (area under curve) positive contribution of integral negative contribution of integral netto integral (net=pos-neg), e.g. effective charge transfer Start End Base start of time interval end of time interval baseline y-coordinate at start and end of time interval By use of the additional buttons <editor> or <printer> the result of the integration may either be passed to the text editor of the system or may be printed out on the system's printer. PVI - 35 - 7.13 Integration with Baseline Each integral may be calculated with respect to the standard y=0-line or by use of a baseline to obtain e.g. 'netto'-charges of current-peaks. Before an integration will be started an input box will prompt and ask if a baseline shall be defined. Selecting the option 'with baseline' the baseline must be defined. The x-coordinates will be the left and the right limit of the time window being defined by the cursors. The y-coordinates of the baseline will be put in by use of the mouse. Therefore two markers may be moved, one on the left time axis t1 and the other on the right time axis t2. Activation and sliding of the markers will be done by consequently use of the <ENTER>-function and of the <ESCAPE>-function. The sequence of baseline definition will schematically be shown in the graphic below. left mark flashing ESCAPE ENTER ESCAPE left mark sliding ENTER ESCAPE right mark flashing ENTER ESCAPE right mark sliding ENTER baseline defined INTEGRATION 7.14 Printer Hardcopy - < HARDCOPY > The displayed diagram may be put out via the line printer hardcopy function. After the selection of HARDCOPY, an additional menu appears on the display unit. Both the parameters for the screen copy to be drawn up and the active output device can be entered and clicked here. After confirming the operation, a part of the screen is inked. The reason for this is that the majority of devices in use are black-and-white printers, which will only produce a copy if all the current data and parameters have been resolved properly. Before output a menu will offer the setting of the print parameters. Thus the size of the hardcopy and its orientation can be selected to certain PVI - 36 - requirements. The printer type as the printer's IEEE interface number may be changed for different devices. Finally the output may be started and a form feed may be enforced. 7.15 Create ASCII-Data List - < DATA LIST > To transfer the measured <E,I,t>-data to other computer systems, the actual data may be converted to an ASCII-data-list. This list may be put out at a printer, may be transferred to the text-editor of the UTIL-software or may directly be saved to a MS-DOS compatible device. For export of ASCII-data PVI offers an additional menu. This menu is divided into three sections: <PVI-data>, <ACQ-data> and <parameters>. If no ACQ-data had been measured the middle section dealing with ACQ-data will be covered by a light red bar indicating that no transfer of ACQ-data is possible. The ASCII-list of PVI-data and of ACQ-data must be created separately as there is no common time base for both types of data. At the moment no interpolation to the contrary time base has been provided. 7.15.1 Listing PVI (E,I,t)-Data Four columns of data may be listed - index - time - potential - current number of order of measured point measure time measured potential measured current Each of the columns may be selected by a separate toggle-switch. An activated column will be marked by a small green 'LED' right to the corresponding button. As all data will be passed via a common basic stack of restricted length only a certain number of rows can be passed to e.g. the texteditor. The stack size is given at the bottom right of the menu and the calculated maximum number of rows to be passed will be given in 'max rows'. The amount of data and the region of interest will be indicated by use of indices 'index'. PVI - Data - Start - Length - End - Step - 37 - dimension of data field starting index of list length of list ending index of list step width of output Considering the amount of data and the data density a selective output will be possible by use of these parameters. After all settings have been done the output will be started by use of the button <create PVI-list> at the top of the menu. 7.15.2 Listing ACQ-Data Six columns have been provided to put ACQ-data - index - time - Chann0 - Chann1 - Chann2 - Chann3 number of order of measured point measure time analog CH0 the intermediate analog channels analog CH1 CHx will be assigned to the first analog CH2 four of all activated channels analog CH3 by the analog channels setup. Each of the columns may be selected by a separate toggle-switch. An activated column will be marked by a small green 'LED' right to the corresponding button. As all data will be passed via a common basic stack of restricted length only a certain number of rows can be passed to e.g. the texteditor. The stack size is given at the bottom right of the menu and the calculated maximum number of rows to be passed will be given in 'max rows'. The amount of data and the region of interest will be indicated by use of indices 'index'. - Data - Start - Length - End - Step dimension of data field starting index of list length of list ending index of list step width of output Considering the amount of data and the data density a selective output will be possible by use of these parameters. After all settings have been done the output will be started by use of the button <create ACQ-list> at the top of the menu. 7.15.3 Control Parameters of ASCII-List Output The most right section of the ASCII-list menu offers selective use of output parameter. Usually text delimiters will be the <SPACE>-character. Use of import filters, which may demand special characters to format a text, three control characters may be defined - EOD End Of Data character - EOL End Of Line character - EOF End Of File character To change a control character activate the corresponding button and put in the new control character. In addition to the character itself, its ASCII-code and the hexadecimal code will be indicated additionally. A additional toggle switch offers selection if a block of header text containing information about the measuring condition shall be put out too. Header output will be indicated by a green 'LED' right to the <header> button. PVI - 38 - 7.15.4 Output of ASCII-List After the output of the ASCII-list has been activated a series of selective menus will guide to the final list device. The list device will be selected by a small menu, appearing after the listing has been started. An example of an ASCII-data-list will be given in the appendix. a) b) c) The data list may directly be passed to a line printer. When selecting this option a menu will offer the possibility to set the output parameters according to the addressed printer. Sending a data list to the texteditor offers two modes of output, either by creating a new list or by appending the data to an existing text. By the direct to DOS option the data will be saved directly to a MS-DOS device. The default data path of an ASCII-list to put be put out, data will be defined within 'setup' of the UTILprogram. 7.16 Saving & Loading of Measurement Data - < DiskOps M Data > The functions which will be used to save and load measure data are the same as being described in other parts of the THALES-manual. The button <DiskOps MData> will lead to a submenu offering disc-i/o-operations. The following menu-points will be offered: 7.16.1 'load file' - < OPEN > - The selected control data file will be loaded to the editor. 7.16.2 'save file' - < SAVE > - Saves control actual control data to the selected subdirectory. For more information kindly refer to other sections of the THALES-manual, where the disc-ops have been described in detail. PVI - 39 - 7.17 Evaluation of Other Time Data Time data of the format (E,I,t) will be recorded by e.g. CV or IE. To display and evaluate cyclic voltammogramms CV and stationary current potential curves IE two input functions have been provided: loads a cyclic voltammogram loads a stationary current potentiyl curve NOTE: Due to the different file structure of the measure data files of PVI, CV and IE these function will work for the loading option only.
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