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• Inside WinS (paper presented at Applied Superconductivity Conference 1998, Palm Desert, CA)

Minimum computer requirements

1. Pentium 75 MHz or higher
2. Win95 or NT
3. 16 Mb or more extended memory.

 The file "WinS.zip" is an archived file. Create temporary directory, put this file there, find any zip unpacking utility (i.e. Windows Commander) and unpack this file. After procedure is completed, you will see three new folders: DISK1, DISK2 and DISK3. You can move their content into one directory or can copy them into three 1.44Mb floppy disks. Find file setup.exe in DISK1 folder, run it and follow the installation guide. Let me know if you have any problems during installation. Examples and documentation are included. WinS upgrade can be installed above the existing version. To remove program use standard add/remove utility located at the control panel.

To download archive file "WinS.zip", please click here: (2766k),

Click here if there is a problem to run program after installation

Version 1.28 updated September 28, 2000

• Version 1.28 Pi-junction becomes a reality. Model for pi junction is added to simulator. Examples show voltage-magnetic field dependence obtained for squid containing pi-junction (Psquid.sch), how pi-junction affects JTL (Pjtl.sch), and how rsfq toggle flip-flop benefits from using pi-junctions (Pflipflop.sch). Flip-flop does not need to use large storage inductance, and does not require extra bias current for pi/2 shift in storage interferometer. Separate monitor images are working much faster with LJJ, PTL, and JTL.
• Version 1.27 In previous version the custom sub-cell with the number of more than nine parameters caused program crash. In this version this problem is fixed. Short description of circuit can be added to the design. IV-monitor can be used as a fluxon counter during current-voltage-curve simulation giving actually current-number of fluxons curve. Two new distributed phase and voltage monitors allows the fluxons visualization in the Josephson transmission and Passive transmission lines.
• Version 1.25 External parameter can be moved without loosing the referenced parameters. The elements, which have one of the parameter referred by external parameter can be moved too since the parameter is locked within external element box.
• Version 1.25 Send mail... is added to file menu.
• Version 1.24 Element editor is not "jumping" now. If more than one parameter have been changed, dialog is not closing upon clicking OK button. It shows all changed parameters in red, and will close after the second click of OK button.
• Version 1.24 There was bug in compound element, which crashes computer at multiple copying them to clipboard. It is fixed now.
• Version 1.23 The font size for each window types (schematic editor, display, and logic analysis windows) can be set separately by clicking right mouse button while its pointer is located in selected window. This invokes context menu with menu item 'Font Size'. Other menu items are for already implemented commands.
• Version 1.23 Each monitor can open separate window to show just one curve associated with this monitor. This window is an OLE curve.ocx control. Design-time license of this control is available upon request. Select 'Help' menu item in controls context menu to see details. See also enclosed example LJJ_ALL.sch
• Version 1.23 IcRn and McCumber parameter can be set same for all junctions in whole circuit including subcircuits from the File->Preference menu item.
• Version 1.21 Three new monitors are added for Long Josephson junction. The distribution of instantaneous voltage (see LJJ_v.sch example) and phase ( see LJJ_p.sch) can be observed as a function of time. Fluxon position vs. time is also available (see example LJJ_t.sch).
• Version 1.21. Separate menus implemented for different processes.
• Version 1.20. There is a New Year gift for Long Josephson Junction (LJJ) community. LJJ is now available in WinS. It is very easy to create, modify, and connect them to RSFQ circuit and other superconducting elements.
• Versions 1.20. In Display window axes may be switched by pressing right mouse button. This affects only IV curves.
• Version 1.20. In Display window cursors show all values for curves that calculated forth and back. Typically these are IV curves.
• Version 1.20. 'Open Old File' menu item serves to retrieve files written with WinS versions older than 1.07. Normally it should open those files automatically, but if the problem is experienced, use this menu item. It is recommended to save old files immediately after opening. This option was introduced after the new version of 'MFCVCRT.DLL' library, which improper treats read file exceptions. This version of WinS is safe and compliant with this.
• Version 1.19. 'Show all' function allows seeing hidden elements and removing them.
• Version 1.19. Circuit animation is available now. Junctions change their color during switching. This allows seeing circuit operation and gives an easy way to detect fault operation. Animation also shows over-biased (at certain level) junctions. Enjoy this new feature!
• Version 1.18. Two compound elements are implemented. Josephson transmission line (see JTL.sch example) and Passive transmission line (see PTL.sch example).
• Version 1.18. Statistics shows the total bias current, including all currents in sub-circuits.
• Version 1.17. There were problems with reading old files. Now it should be OK.
• Version 1.17. Statistic now calculates number of all elements including sub-circuits.

Reported bugs... Fixed problems are black and the red ones in progress

• I also realized that I wish there were a "rotate" and "flip" -> "horizontal" or "vertical" on the "edit" pull-down menu. In general, things that the mouse can do should appear somewhere on a menu with the mouse hot key for doing the same function. That is, one should be able to select a component and then issue a menu command for performing the function.
• I selected a number of elements and then tried double-left clicking to make the whole group rotate (the ability to group elements and then perform operations on them as if they were a single element would be a nice function to have). Sometimes a single component would rotate. Others times the component under the mouse would disappear!!! There is definitely something wrong here
• There is a problem with shortening an element. It is understandable that one cannot shorten a junction or resistor. It should definitely be possible to shorten a wire -- or the wire element should start out much shorter.
• I am thinking that it would be good to provide an option to show even TWO connected terminals as a black dot. After connecting two terminals, it is sometimes hard to know where to connect the terminal of a third element.
• I don't like values displayed in the format "3.". This should either be "3.0" or (probably preferable) shown exactly as the user entered it, thus allowing "3.0" or "3.000" as the user wishes

1. I hope my colleagues mentioned here will forgive me for some missing facts and dates and help me to add more information to this topic.
2. It was very old program 'KOMPASS' created at Moscow State University in Konstantin Likharev's group. It ran on 'BESM-6' (something like Big Electronic Simulation Machine), which ate perforated cards, and needed couple days to cook results.
3. 1987. Under close supervising by Vasily Semenov the first interactive 'FORTRAN' version of this program called 'S' was created on 'Nord' computer based on 'SINTRANIII' operational system. The source code was completely new but was based on old ideas.
4. 1988. The program had been moved to IBM PC XT (286 12 MHz), still was interactive (using prompt line), graphical output was added.
5. 1989. Stas Polonsky left theoretical haven, joined Semenov's group and started his work on creating new interface for old simulation program. Stas and Vasily Semenov used partially source code of 'S' program for this, and actually even did some changes in it. At this time 'PSCAN' was born and two programs were developed independently.
6. August 1989. First attempt to use Windows Development Kit to move 'S' into Windows failed because the program speed was extremely low. Part of the source code was still written using FORTRAN.
7. February 1990. 'S' was rewritten using Ms C v.5.1 to be completely C program compatible with UNIX.
8. 1993. The automatic optimization of the parameters was implemented. The idea is common and simple, but tuning all the optimization parameters took a lot of time.
9. 1995-1998 Finally 'S' has been moved to the Win95 platform as a true 32-bit application. Speed appeared to be the same as for 32-bit extended DOS mode. The program got name 'WinS'. Schematic editor, simulator, and logic analysis are in the same program. It is easy to install and use it.

Q: I was confused by the box with the units prefixes, and that's what I was trying to use HELP to clarify. Can I change the "m" to "u" if I want critical currents in microamperes?

A: No, the values of units are fixed and shown in the right column of Preference->Defaults menu. You can change only appearance of the units in the schematic window.

Q: After installation of the latest version of the WinS, I couldn't read files created with the previous versions.

A: It means that you have simultaneously old and new versions on your computer. File created with the older version while the new one is installed may be not available for new version. This may happen only for version older than 1.07. Solution is the change file Last modified date parameter for early date.

Q: Spent the evening trying to install the wins 1.13 simulation program. I am consistently receiving the following error during installtion on both NT4 and Win95: "File transfer error-115." This error occurs during the "Copying Shared DLL's" at 42% of the installation program.

A: Most probably you have older versions of such DLLs and one of them is used by an application running on your computer (it may be background antivirus or any other utility). Close all applications and run WinS setup again. If doesn't help, let me know, and please leave your valid email address.

Q: The program needs a zoom-full-scale that automatically includes all elements. I had a circuit that just would not work. No matter how many monitors I deleted, I still got a message about monitors missing. It turned out that there was a stray monitor out of the field of view!

A: Use "Show all" item in "View" menu to display all elements of the circuit.

1. Please consider that some of the examples are valid only for latest version of WinS.
2. The example files can be found in the folder "..\wins\examples" after installation (see also Examples in help). WinS automatically starts in this directory, thus these files can be seen in the "Open file" dialog.
3. Monitorp.sch shows the use of IV (average phase) and digital monitors. This example is based on two-junction interferometer. Open "Display" window to see result of simulation.
4. Average.sch is an example of use the average voltage monitors with different average times.
5. Monitorv.sch shows the use of voltage monitors. This example is based on two-junction interferometer. Open "Display" window to see result of simulation.
6. Monitorc.sch shows the use of current monitors. This example is based on two-junction interferometer. Open "Display" window to see result of simulation.
7. Progcurs.sch illustrates the programmable current source use in the regime that produces current steps.
8. Progcurp.sch illustrates the programmable current source use in the regime that produces current pulses.
9. Voltage.sch contains two voltage sources with the different internal resistances. This resistance should be taken into account when the low resistance load is used. WinS uses this internal resistor and two currents to perform this source. The rvoltage.sch shows the equivalent circuit of the voltage monitor (or how it is presented internally).
10. Phase.sch demonstrates introducing magnetic field (or phase) into two-junction interferometer with the phase source. WinS uses for this element the inductor and two currents that is shown in the equivalent circuit presented in iphase.sch example.
11. Flipflop.sch is an example of digital monitors used in margins simulation and optimization of the RSFQ T-flip-flop. Display window shows the right operation margins of the circuit with the cursors positioned at the point where circuit will be tested during margins calculations and parameter optimization. Open logic window to see stored margins.
12. Avoltage.sch and Fmonitor.sch are examples of the average voltage and frequency monitor used in margin calculation.
13. DCtoSFQ.sch is a DC-to-SFQ converter. See logic window for margins.
14. SFQtoDC.sch is a T-flip-flop with SFQ-to-DC converter. It is a good demonstration of the frequency monitor used in margin optimization. Open logic window to see stored margins.
15. Avseq_dc.sch is a T-flip-flop with SFQ-to-DC converter. It is a good demonstration of the average voltage monitor used in margin optimization. Open logic window to see stored margins
16. Ivcurve.sch is an example of using IV monitors for IV calculation. Ivp.sh shows how the other parameter than the bias current can be used for parameter-V curve.
17. Nrjunctn.sch shows IV curve of the junction in nonlinear resistive model with voltage gap and hysteresis.
18. Sin.sch demonstrates functionality of the current function generator and also how to calculate rf induced steps in IV curve of the junction.
19. Long_jtl.sch demonstrates hierarchy, and subcircuits. It is based on 50 junctions JTL and demonstrates the SFQ repulsion effect.
20. Cvc.sch is an example of the external parameter used to take subcircuit parameter for IV simulations.
21. JTL.sch is an example of the Josephson Transmission line packaged into the single element.
22. PTL.sch is an example of passive transmission line packaged into the single element.
23. Ljj_zfs.sch - illustrates the first and the second zero magnetic field Fiske step (IV-curve).
24. Ljj_ffs.sch - Flux flow step at magnetic field corresponding b e=2.5 (IV-curve).
25. Ljj_hfs.sch - Flux flow step position at gamma=0.5 as function of magnetic field (IV-curve).
26. Ljj_v.sch - Instantaneous voltage along the long junction (LJJ voltage monitor).).
27. Ljj_p.sch - Instantaneous phase along the long junction (LJJ phase monitor).
28. Ljj_t.sch - Shows how fluxons move in Long Josephson junction. (LJJ fluxon tracks monitor).
29. LJJ_ALL.sch - demonstrates the use of the monitor graphic window (Curve OLE control)

1. Comprehensive analysis of the schematic before starting simulation is implemented. It checks for staying along elements, wrong element connections, etc.
2. The selected new element from toolbar or menu can be canceled by using ESC key.
3. To delete selected items use the accelerator key -DEL
4. There is 'Preferences' item in the 'File' menu. It lets you to change default elements values, switch between real and reduced units, and also change simulation accuracy, time steps, and etc.
5. WinS stores 200 deleted elements. You can retrieve them using Alt+Backspace, CTRL+Z or 'Undelete' from menu
6. Select menu item and press F1 to see help, or use help menu to get a list of help topics, searching key words etc.
7. The terminal of "Current monitor" reflects the monitor connection to the measured element. It is black if connected and blue if not.
8. Programmable current source has an option of repeating the digital pattern after some specified number of periods. It also has the rise and fall times, the delay to the start of the first pulse position, the 'on' time, and the period, just as in SPICE.
9. "Digital monitor" can keep a track of voltage. The simple change of its attribute changes "Digital monitor" to "Frequency monitor". The last one can be used in optimization and margins calculations at the output of SFQ-to-DC converter or in the voltage state logic.
10. Dialog "Mouse box" can be used to reprogramming mouse buttons. This makes easier to make selection between elements and their attributes. Flying dialog box can be placed in any place in the screen, resized, open and close at any time you need. It is common for all open circuits.
11. There is an easy way to copy elements from one document to another. Select desired elements in one window, press CTRL+C to copy them into the WinS clipboard, make active another window, and press CTRL+V to paste these elements in this window.
12. Select group of elements in schematic and add them as a single group reference into logic window. This changes them simultaneously during optimization. This group for example may include all inductance's, which all together may vary due to the fabrication parameters spread. By editing group element one can change all referred elements simultaneously.
13. Delete element from logic view list using Ctrl+left mouse button and edit element name by using right mouse button. By selecting element in logic window, one can see as marked in schematic window all reffered elements.
14. The beginning of secondary coil of the superconducting transformer is marked, and can be changed.
15. Time analysis is a background process, and can be terminated with ESC key or by using Analysis-Stop menu item.
16. Average voltage monitor has two parameters: average time and tolerance. If average time is set to negative value, averaging is proceeding for infinite time, as it was only one option in previous versions. By selecting proper average time this monitor may be used for margins calculation and optimization. These require second parameter - tolerance. Same circuit was taken for margin calculation with frequency monitor - SFQtoDC.sch, and with average voltage monitor - avsfq_dc.sch, and they show similar margins. Average phase monitor is still has infinite average time, because itself it is useless, but it is reserved for IV simulations.
17. Josephson junction can be described in resistively shunted and in nonlinear resistance models. Nrjunctn.sch shows IV curve with the gap voltage and hysteresis.
18. Function generator can produce sine wave and triangular-wave bias current. It is useful for rf induced step simulations (see Sin.sch example).
19. Select elements with the dragged box by the left mouse button box. Deselect elements by the same way using right mouse button.
20. . Hierarchy structure based on sub-circuits is available. See Tree menu and related help files.
21. External parameter and parameters of the sub-circuit can be used for margins and optimization. See examples Allpar.sch and Extpar.sch respectively.
22. Tree control shows the whole structure of the circuit, and allows selection and edition of the sub-circuit.