FAQ - Hardware

From within VersaStudio go to the Help tab and select 'About' to view your instrument's options.
When questioning the working order of your Princeton Applied Research potentiostat/galvanostat, the first thing you should do is re-initialize the system (except for PARSTATs and VersaSTATs).  After that, you should perform some basic experiments with resistors, which we refer to as "Dummy cells".  Most Princeton Applied Research systems have an internal Dummy cell within the system (please refer to the User's Manual for your system for directions on how to switch from External to Dummy cell) so as rule out any problems with leads.  To test the system out to the leads, a resistor of known value that will allow proper testing of the system (sized such that the desired current and/or potential fall within the desired ranges) is also recommended.  To connect across a resistor, attach the Working lead (and the Sense lead if applicable to your system) to one side of the resistor and both the Reference and Counter leads to the other side of the resistor (with the Reference closest to the resistor).  This is what is referred to as a "Two-Terminal" connection.

With the system set to either the Internal Dummy cell or connected to an external resistor, apply a potential (or current in galvanostat mode) and determine if the corresponding current (or potential in galvanostat mode) is the expected value based on Ohm's Law.  For example, with a Princeton Applied Research 263A system set to its Internal DC dummy cell (a 10 kΩ resistor), an applied potential of 1 V should give a current reading of 100 µA (provided the current range is set to Auto or 100 µA) ± allowable tolerances.  Likewise for this same system, an applied current of 100 µA in galvanostatic mode across this 10 kΩ resistor should give a potential reading of 1 V ± allowable tolerances.  You may also run scanning techniques with the Dummy cell, each data point obeying Ohm's Law of E = IR.

If you feel that your system is not functioning properly with the Dummy cell, please contact the Technical Support department.  If the Dummy cell results appeared normal and your actual experiment is not giving the expected results, examine your setup carefully, giving special consideration to cell design, environmental interferences, bad reference electrode, bad connections, or grounding problems. 
An "E overload", or potential overload, can actually be one of either two conditions:
  1. The maximum input voltage (±10 V for most) of the differential electrometer has been exceeded.
  2. The compliance voltage (the maximum amount of voltage the power amplifier can provide across the working/counter interface) is at its maximum.
The E overload light will not distinguish between these two different conditions, so it is the responsibility of the user to detmeine which is the more likely cause.  One special note: if the leads are not connected to a cell, the voltage reading on the display of the system will "float" randomly and may report an E overload under these conditions.  This does not damage the system and occurs because there is an open loop in the differential electrometer circuit.  This would cease if you were to connect the working and reference electrode leads or connected a dummy cell across the leads.

An E overload due to exceeding the maximum input of the electrometer is usually seen when working with a low impedance cell (i.e. fuel cell or battery) in galvanic mode.

An E overload due to exceeding the maximum power amplifier output is usually a more serious condition because the full compliance voltage is being applied to the cell, causing possible damage to your electrode.  This condition is most often caused by a bad reference electrode or failure to connect the reference electrode.  Without a reference, the power amp continues to pump current into the system until it either overloads or reaches the desired potential (which it obviously cannot do without the reference in place).  Another common occurrence of this type of E overload is when working with highly resistive organic electrolytes.  Again, the power amp is pumping current trying to achieve the requested potential at the working electrode, but it must also overcome the iR drop between it and the working, which can consume many volts depending on the resistance and the distance.  To overcome this situation, reduce the distance between the counter and working electrodes.
An "I Overload", or current overload, is caused when the current flowing through the I/E converter exceeds the limit for a particular current range.  If you are getting a constant I Overload signal, try selecting either a higher current range or Auto Current Range mode.

If you are receiving an I Overload signal on the highest current range, it may be that your experimental design is in error (i.e. too large a sample or short circuit condition).  If you are performing an experiment in Auto Current Range mode, you will often see the I Overload (or "Ovl" or "Overload") light flash for a second as it approaches the limit for one current range, but extinguishes as it goes to the next highest current range.  This event does not affect the system or the data.  

In some instances, you may see the I Overload light flicker at a high frequency; this usually indicates some high frequency noise or highly capacitive cell is resulting in current spikes.  

Still another instance of an I Overload is when the system goes into oscillation, a condition which can be caused by a bad reference electrode, highly capacitive cell, bad connection at the leads, etc.  For more information on oscillations and noise, see the General section. 
Most of the Princeton Applied Research systems (PARSTATs, VersaStats, 263A, 283) can be configured into a ZRA.  In this configuration, no potential or current waveform is applied to the sample so this is considered an "open-circuit" technique.  For this special configuration, the electrochemical cell will be connected to the cable leads of the potentiostat is a different manner:
  • Working lead (green) is connected to one of the samples
  • If the Sense lead (grey) is available, connect it to the same sample as the working electrode
  • Ground lead (black) is connected to the other sample
  • Reference lead (white) is connected to the reference electrode
  • Counter lead (red) is not used
The configuration is used for such techniques as Galvanic Corrosion (current characteristics of two dissimilar metals immersed in a solution and measured as a function of time) or Electrochemical Noise (current and potential characteristics for two samples of the same composition measured as a function of time).  

Note:  Models 273 and 273A cannot be configured as an open-circuit ZRA in this manner.
You can check that your potentiostat is measuring the correct open circuit potential using a battery in series with the reference electrode.  To perform the test, assemble a cell and attach the potentiostat leads as shown in the figure below.  The reference electrode lead (RE) and the counter electrode lead (CE) are connected to one side of the battery and the sense lead (SE) and the working electrode lead (WE) are connected to the other side.  Note that some cables do not have the grey sense lead.  The black ground lead is not connected.  This should result in a stable OC measurement of about 1.5 - 1.6 V if the battery is fresh.  This value can be verified using either the Open Circuit or CV actions in VersaStudio, the Ecorr vs. Time technique within PowerCORR or the CV technique within PowerCV.  If you are using CV, make sure that your selected initial and final potentials are versus OC.


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Connection of the black ground lead on your Princeton Applied Research potentiostat/galvanostat is recommended for the following instances:
  1. The ground lead is connected to a Faraday shield surrounding your experimental setup, so that all environmental EMFs that strike the shield will be shunted to ground.
  2. If you have a PARSTAT, VersaSTAT, 283 or 263A system, the ground lead is also used for Galvanic Corrosion measurements to configure the system as a zero resistance ammeter (ZRA).
Thus, for the majority of applications, the ground lead should NOT be connected to anything.  Care should also be taken to avoid accidental contact of the ground lead to other metallic surfaces.  If you do connect it to something that is already at ground, you may actually be forming "ground loops" that introduce noise into your system.  
Your Princeton Applied Research potentiostat system (283/273/273A/263/263A/VersaStat/VersaStat II/6310/BES) has memory just like a computer.  Like any computer, sometimes an error gets introduced into the memory and needs to be cleared.  Unlike your computer, the memory is tied to the internal battery, such that turning the system off and on again does not clear the memory or reset the default values.  The best way to "re-initialize" (analogous to a re-boot) your system is to turn the system off and hold down any one of the front panel buttons.
 
For the 273 and 273A, hold down the LOCAL button at the lower left of the front panel and continue to hold it down as you activate the main power switch.  For the 273/273Asystems, the LCD display will show "System Re-Initialized" and you can then release the LOCAL button.  

For the 263/263A-2/283 systems with a LCD display on the front panel, the display will show "Please Release Key" and the system will be reset after releasing the front panel key.  

For models without front panel LCDs (VersaStat/VersaStat II/263A-1/BES/6310), you can hold in the CELL button as you power on the system and this will re-initialize these units. 
Instrument ROM Version 
273A 202
273 with 97 option    19
273 with 96 option 107
263A 2.19
263 2.19
VersaStat II 2.19
6310 2.19
283 1.04
An FRD100, FRD2000, 1025 Frequency Response Detector, or 5210EC Lock-In Amplifier is attached to a GPIB potentiostat via two BNC connectors and a GPIB connector.  

For the GPIB connection, the cable is run from the GPIB port on the back of the the FRD/LIA and "piggy-backed" to the GPIB connector on the back of the potentiostat.  We recommend the use of the National Instruments GPIB-USB-HS GPIB Adpater / Cable assembly for communications between the computer and the potentiostat.

Please note that the FRD/LIA is delivered with an RS232 cable and software designed for diagnostic testing of the FRD/LIA only.  This RS232 cable must NOT be connected when trying to perform EIS measurements with the FRD/LIA and potentiostat.  Failure to disconnect from the RS232 cable prior to measurements will result in an inability to communicate with the FRD/LIA properly.  

The BNC connections between the compatible potentiostat and FRD's / LIA are as follows:

Potentiostat Model   FRD 100 / 2000 1025 5210EC
263A-1 or 263A-2 Front Panel "EXT INPUT" Rear Panel "OSC OUT" Front Panel "OSC OUT" Front Panel "OSC OUT"
  Front Panel "OUTPUT" Rear Panel "A INPUT" Front Panel "SIGNAL INPUT" Front Panel "A" Input
273A/92 or273/92/96 Rear Panel "AC INPUT" Rear Panel "OSC OUT" Front Panel "OSC OUT" Front Panel "OSC OUT"
  Rear Panel "MULTIPLEXED OUTPUT" Rear Panel "A INPUT" Front Panel "SIGNAL INPUT" Front Panel "A" Input
283 Front Panel "EXTERNAL INPUT" Rear Panel "OSC OUT" Front Panel "OSC OUT" Front Panel "OSC OUT"
    Front Panel "MUX" Rear Panel "A INPUT" Front Panel "SIGNAL INPUT" Front Panel "A" Input
The 263A with 2A option installed is equipped with two cell cables: a three terminal cable (C0345) and a four terminal cable (C0366) which contains an additional grey colored Sense lead.  For working with currents above 200 mA, one should use the four terminal cable (if only using three electrodes, the Sense lead is connected directly to the working electrode, with the working lead connected above it) and must operate the system in High Speed mode.  The purpose of bringing the Sense lead out to the cell when working at higher currents is to eliminate the iR drop error resulting from the working electrode lead (which is an alligator clip).  When bringing the Sense lead out to the cell, you are then required to run in High Speed mode for the electrometer to operate correctly at the higher currents.
Use the Virtual Potentiostat 32 software for access to these features.  Virtual Potentiostat 32 software was included with the potentiostat purchase.
No, the Windows 95 operating system does not support the USB communications needed to run a PARSTAT.  Windows 98 or higher will work.
For laptop computers, a PCMCIA-GPIB card or GPIB-USB-HS converter cable from National Instruments can be used for communications with our potentiostat/galvanostat systems.  The cards are plug-and-play and the National Instruments software and drivers are installed and configured the same as for the PCI-GPIB card.
Princeton Applied Research instruments do not use the NI 488.2 language.  Commands sent to the instrument using this language will give an error message.  When trying to verify that your potentiostat is communicating through the GPIB card, you need to change the indentification string in the NI communicator from "*id?" to "ID" which is a command the potentiostat will understand.  A description of this command and others can be found in the Command Set Handbook for your GPIB-controlled potentiostat.
For Windows® XP, 2000, and NT, the installation of the GPIB card and drivers are the same.  Install the National Instruments (NI) GPIB software first, power down the PC and install the PCI-GPIB card.

After re-booting the system with the card installed, the "NI 488.2 Getting Started Wizard" will appear.  At this point you should select "Verify your hardware and software installation" to insure that the GPIB card and PC are working together.  Note:  Do NOT select "Communicate with instrument" option.  Princeton Applied Research systems do not use 488.2 language so this step will fail.  Instead, after the software and hardware has been verified, check the box "...not show at Windows startup" and close the NI-488.2 Getting Started Wizard window.

Go to Control Panel and select "GPIB".  Set the properties as shown below, with Bus timing set to 2 µsAssert REN when SC enabled and Auto Polling disabled.

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To activate the National Instruments Windows® XP/2000/NT driver to run DOS applications after it is installed, please locate the C:\Winnt\System32\config.nt file, open the file with Notepad (or other text editor) and follow the instructions at the bottom of the text for configuring for DOS applications.  Note:  You must re-boot the computer for changes to take effect after editing the config.nt file.  The last lines of this text file should appear as shown below, with "REM" removed from the last line:

REM***To run DOS GPIB applications, uncomment the 
REM***following line
device=C:\PROGRA~1\NATION~1\NI-488.2\DOSWIN16\Gpib-nt.com
This document is provided as a supplement to the documentation included on the National Instruments CD.  This document specifically addresses the installation and configuration of the PCI-GPIB card to operate with Princeton Applied Research hardware and their supporting software in a Windows® 95/98 operating system.

Included with the National Instruments PCI-GPIB card is an instruction sheet titled "Getting Started".  Follow the instructions on this sheet for GPIB software and card installation.  Step 4 of this document discusses the "Getting Started Wizard" that allows you to "Verify your software and hardware installation", and to test communications with the attached hardware (i.e. the potentiostat).  Provided the NI card and software were properly installed, a "passed" status depicts the outcome of a successful installation.  If everything passed, click Exit to continue.  Any failed steps in the verification process should be addressed with the National Instruments documentation on their CD or contact National Instruments Tech Support at www.ni.com for troubleshooting tips.

The next step in the verification process is to "Communicate with your instrument". NOTE!  Due to differences in program communications between National Instruments and Princeton Applied Research, this may give false information.  At this point, it is best to check the box "Do not show at Windows startup" and click the "Exit" button to exit the Getting Started Wizard.

PCI-GPIB Card Configuration for Windows® 95 and 98

Once the National Instruments GPIB card and drivers have been installed, you may proceed to the configuration of the GPIB driver to run optimally with the Princeton Applied Research systems.  For Win 95/98 systems, the National Instruments driver properties are located within the Device Manager.

Go to Start > Settings > Control Panel > System and click on the Device Managertab.  Once there, you need to select the National Instruments GPIB Interface line such that it is highlighted blue.  After highlighting, click the Properties button in the lower left of the System Properties window.  This will bring up the National Instruments Interface Properties window which has two separate pages.

The General page contains a box that needs to be checked in order to run any DOS applications under Win 95/98. (Note: your DOS software will not run if this box is unchecked.  Also, ensure that your Config.sys file no longer contains the ?Device=C:/pathname/GPIB.COM? command; this will conflict with the new Windows driver.)


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Next, enter the Device Templates window.  Device Name attributes need to be changed such that the Readdress box is checked for each device connected to the GPIB card (DEV14 is the factory default GPIB address setting in our systems; if using multiple systems each must have a different setting).  Note: GPIB0 is the card ID in the system.  This should remain GPIB0 unless you have multiple GPIB cards in the same PC.  After making these changes, click OK to return to the Device Manager.

Back at the Device Manager, highlight the PCI-GPIB line and click the Properties button, which brings up the PCI-GPIB Properties window.

On the PCI-GPIB Properties window, click on the NI-488.2 Settings tab.  In this section, ensure that the Interface Name is GPIB0.  Next, click the Advanced.. button in the lower right of the window.

Once on the Advanced NI-488.2 Settings window, change the Bus Timing to 2 µsec, disable the Automatic Serial Polling, and enable Assert REN when SC.  After making these changes, click the OK button, then click OK again to go back to the PCI-GPIB Properties window.

Finally, click the Resources tab and verify that an Interrupt Request and two Memory Ranges have been assigned to the card.  Also, verify that the bottom of the screen reads "No Conflicts".

This completes the installation and configuration of the National Instruments PCI-GPIB card and you may now exit the Device Manager, reboot the computer, and proceed with the installation of the Princeton Applied Research Software.
Currently, the same driver that controls the PCI-GPIB card (ver 1.60) will work with a PCII/IIA GPIB card.  You can download this driver from the National Instruments web page (www.ni.com) but you will need nine diskettes for this download.

Once the drivers are downloaded, you need to install them on your PC.  Go to Start > Settings > Control Panel > Install/Remove Program and use the Win 95/98 Install Wizard for software installation.

Before installing the card (if the card is already installed, you need to remove it), you must configure the set-up to a PCII configuration as opposed to a PCIIA configuration (see your PCII/IIA manual for this configuration change at the I/O switches).  You should also check your system for available interrupts before installing your card (this information can be obtained by printing the system summary, Start > Settings > Control Panel > System >Device Manager, then click Print) so that you are aware of what is available for configuration.

Before physically installing the card, you need to go into Start > Settings > Control Panel > Add New Hardware.  Since the GPIB card is not a plug-and-play card, you need to select No instead of Yes (Recommended) for the auto setup.  On the next screen, select S, then select National Instruments on the screen as the manufacturer.  Then select the GPIB-PCII and click the Next button as Windows 95 attempts to assign non-conflicting resources.  Once the resources are assigned, DO NOT reboot the computer; go to Control Panel > System Properties > Device Manager.  Open National Instruments GPIB Interfaces, double click on the GPIB-PCII, and click on the Resources tab (Figure 1).  Change the resources to match those on the card (change the I/O address on the card to 02B8-02BF), for Basic Configuration 1.  Make sure there are no conflicts.  After making these changes, click the OK button, power down the system and install the card in the computer.

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After rebooting, go to Control Panel > System > Device Manager.  If you click once on the National Instruments GPIB Interface, then click on the Propertiesbutton, you should get the following screen (Figure 2).  If you check the box for Enable Support for DOS GPIB Applications, you can run DOS applications (i.e. M270 software) with this driver.


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Next, go back to the Device Manager > National Instruments GPIB Interfaces > GPIB-PCII, then click the Properties button and select the NI-488.2M Settings tab.  Once there, you should click the Advanced button within this window and change the settings in the resulting window to match those in Figure 3.  


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After making these changes, exit back to the Desktop and go to the Start > Programs > NI-488.2M Software for Windows® 95 and finally, click on the Getting Started Wizard icon to test that the setup was successful.
The 394/384B and 303A systems can be tested up to the pin jacks in the rear of the 303A.  This can help determine if the observed problem is prior to these points (i.e. in the 384B/394/Potentiostat or the 303A Electrometer or CPU) or if it is after these points (i.e. in the reference electrode, capillary, valve body, cell, etc.).  

To perform this test, you will need a 1 MΩ resistor and to make connections to this resistor and to the 303A pin jacks as shown in the diagram below.  Once you have the resistor connected, you need to empty the cell bottom of its electrolyte so that there is no continuity between the 303A's electrodes.  

Next, perform either a LSV (linear scan voltammetry) or CV (cyclic voltammetry) experiment (Note:  you cannot test a resistor with SWV or pulse techniques).  

If you perform a CV from 0V to 1V and back to 0V, your current readings on the graph should obey Ohm's Law with the current apex being 1 µA (corresponding to 1V across 1 MΩ).  If this test shows the expected results, then the problem is most likely with the cell (303A) or mercury flow.

Please note that we offer our Application Note T-3 "Model 303A SMDE Maintenance and Troubleshooting Guide" that is an excellent resource for anyone using the Model 303A.  It may be found by following this link:  Application Note T-3


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If the 303A is to be stored for more than four weeks without use, the Mercury should be completely drained and the Valve Body mechanism removed and cleaned to ensure that small Mercury drops are not left inside to oxidize and result in a clog.  Repairs resulting from such leftover oxidized Mercury can be costly in rebuilding / replacing the valve body's components.

Also, the Reference Electrode Jacket needs to be removed, and placed in a sealed container of its own filling solution to prevent the frit from drying out.  If this is not done, the frit will be damaged by cracks that will develop in it as it drys out.

We are pleased to offer our Application Note T-3 "Model 303A SMDE Maintenance and Troubleshooting Guide" that is an excellent resource for anyone using the Model 303A.  It may be found by following this link:  Application Note T-3
This is a simplified quick start procedure for the calculation of results using the Model 394 Trace Analysis System.
  1. Preparation:  Obtain blank, sample, and standards for analysis using your standard method of preparation.
  2. Analysis:  If required, analyze replicates of the blank and the sample by your method.  If you are analyzing replicates, you must run a scan for each replicate and store the results of each curve in a separate file.  If the method of standard addition if employed, then spike each replicate sample with a known amount before the second scan for the standard response.  Alternatively, prepare a simple standard curve and store the results of each curve in a separate file.
  3. Replicates:  (For duplicate analysis only) Recall one of the two duplicate curves into a screen.  Choose Tools > File Math > Add.  Browse the data files and choose the second file of the sample curve.  Choose Tools > Data Math > /Constant.  Enter the number "2" and calculate the average of the two curves.  Store the calculated curve in a new file.  Perform this procedure for each pair of replicates.
  4. Calibration:  Clear all peaks from the screens.  Recall one of the standard addition or standard curve files, choose Results > Peak Search.  Study the plot carefully and note the peak number corresponding to the analyte peak(s) of interest.  You may be able to identify as many as nine peaks for standards calibration and analysis.  Choose View > Data Setup > Sample/Cell and see the list of components 1-9 on the left side.  Enter the concentration of the standard next to the previously noted peak(s).  (If the concentration units are not correct, then go to Options > Experiment > Concentration and select proper units.  Click on OK and exit.)  Click OK.  Notice that the entered concentration now appears in the right column under the appropriate peak.  If you care to identify each peak with an alphanumeric code on the graphical display, then choose Results > Analyze and enter the code in the upper row of boxes corresponding to the peak numbers 1 to 3.  Use the scroll bar near the bottom of the screen to access the other six peaks, if any.  Click on OK and exit the Results/Analysis screen and save the file.  All entries will be saved and presented each time the curve file is recalled.  Repeat for each standard curve to be used in the calibration curve.
  5. Results setup:  Choose Results > Analyze to get to the Standards/Analysis Table.  Observe that the file you had last recalled is shown in the sample file box.  Check the Peak Locate and/or Blank Subract Boxes as necessary.  Choose Standard Curve or Standard Addition Method box.  Choose Blank Subtract and Peak Location if desired.  If you had chosen the peak location option, then the top table will list peaks identified by potential (mV) and peak number.  Also, you will see the recalled data file listed in the Sample box under the filename column along with the measured peak height listed in the Size columns below each numbered peak.  If blank subtract is chosen, then sample and standard peaks will have the blank file subtracted from each for the purpose of the calculation of the concentration in this table.  (Alternatively, you may choose Tools > File Math > Subtract to permanently correct the sample and standard curves for a blank.  We do not recommend this procedure unless one is certain of the consistency of the blank response from sample to sample.)  
  6. Curve file entry:  Click on the Filename box on the left column for the blank, choose Browse and the blank curve file.  The file name should appear in the blank box.  Repeat this procedure for each standard (Std1, Std2,....Std9) by clicking in the appropriate box and Browsing in the file.  (Make sure that you click in the appropriate target box before browsing in the file, otherwise you will read all the files in the same box.)  When all curves are entered in the Results/Analysis Table, choose Find > Calc.  The calculated peak heights should appear in each row along side the concentrations of each standard curve that was entered earlier. 
  7. Calculation of sample concentrations:  Click in the sample box and Browse in a sample curve.  Choose Find > Calc.  Calculated results for all previously identified peaks in the sample file will appear in their respective positions in the sample box row.  Choose Calib Plot, enter desired peak number and click on OK for the calibration plot.
  8. Storage of calibration table:  If one wishes to store the standard curve calibration table for future calculations, choose File > Save As and enter the appropriate file name.  A suffix of *.ANS will be added to the file and stored.
  9. Plotting of results, graph, etc:  Click on File > Page Setup.  Check boxes for Data Setup Parameters, Analysis Results, Graph, Graph/Analysis Results as desired.  When File > Print is chosen, all of the items in the checked boxes will be printed.
To be able to run the 394 software with the 384B, you must have firmware version F0:C1.  The firmware version appears on the front panel read-out when the instrument is turned on.  If you have F0:C1, install the 394 software on your computer and perform the following:

Connect the ribbon cable (C0191) to the RS232 port on the 384B and to your computer COM port on the PC using a 25-to-9 pin adapter.  The best port to put the analyzer on is COM 1.

Set the flow control for COM 1 to Hardware (as opposed to Xon/Xoff) and the Baud rate to 9600.  For Win95, these changes are made within the Device Manager on Ports.

Changing 384B to 9600 Baud rate (refer to 384B manual on page V-52):
  1. Remove 4 screws from the top cover of the 384B.  Loosen the 6 screws around the front extrusions.  Remove top cover.
  2. Look at the left rear corner of the instrument.  On one of the two boards you will find a switch pack with 4 switches.
  3. Change all of the switch positions (S1A=L, S1B=L, S2A=L and S2B=H).  This changes the Baud rate of the 384B to 9600 from 2400.
This should be all that is necessary to get the system communicating with the software.