The route to simulation III
Contents
1. IT a Tee TO ne cane x Tan ia Mire Tine TEE a m ESR i i laring a x he i innan li coy ae o ae ttl lee Ea ate Terap i m KNT ETN ae E Tara ae a Eas Ubi ee ret Wren or PO ie rp es ene T 1 ee Mirar mio ontenan a F Y i ij i i l i i i i i ii IIL eee h alt MMV ERIR A Nh i bir Wa i Rise reel ELETA T i ak Tones bs onan J ss o cat Fae Areare annann gr He ae mids F Rig aR at eT CeEEE nii a eee Fig 2 Input impedance graph and symbolic analysis of input impedance A semi symbolic form i e with values inserted can also be obtained maa p S Equation Editor rt ee 100 00 ete TT LEAL Ee Te Lee TTI LUT September 1999 ELECTRONICS WORLD 739 PC ENGINEERING Fig 4 Analysis of gain and phase expanded to run full screen for easier measurement Fig 5 Typical digital timing chart of a counter circuit with glitch control set at 60 740 Stina cay A bit symchr rer u E at m eae eS O00 text around to make neat diagrams Junction dots are automatically insert ed and symbol annotation is carried out as you go along Wiring is assisted by a dot grid and a good but non adjustable snap to function makes for a good degree of reliability in net list generation Undo and Redo functions have been added with unlimited levels It is now possible to extri2. The manual and help files do not describe these meters as well as those in Workbench or CircuitMaker do However in most cases it is not dif ficult to find out what they are and what they are capable of simply by trying them out The method of use for the oscillo scope signal analyser and multimeter instruments is to select these as icons from the parts bins or component bars as they are called in Tina and wire them into the circuit diagram The other virtual instruments can be selected from the T amp M menu and connected via a virtual probe Instead of expanding an instrument icon to see the controls etc as in other programs the system in Tina is to pick the instrument you want to adjust from the T amp M menu You then get the complete virtual instrument on the screen in a set size Instruments cannot be resized or run full screen but they can be moved around Windows style in order to fit in more instruments or to look at the circuit diagram A typical instrument an oscilloscope is shown in Fig 1 Alternatively you can set up the virtual instrument from a short form menu by clicking right on it but I did not find this method very useful Generally speaking the range and extent of the virtual instrumentation was good Several of the meters from the meter parts bin are noteworthy The power meter will be of interest to those of you involved in AC power circuits as it can give power factor apparent
3. 20 tutorials available or alternatively they can be accessed from the Help menu in which case you get 25 The advantage of accessing them from ELECTRONICS WORLD September 1999 the Help menu is that you can refer to a specific tutorial during work on your circuit perhaps to refresh your memory on a particular topic then flip straight back to the circuit To do this the tutorials need to be trans ferred to the hard disk during the main program installation Although they take up 15Mbyte it is well worth the hard disk space There is also assistance in the form of a self running demonstrator CD I did not find the manual Help files or the demonstrator very useful individ ually When they are combined with the tutorials though it was possible to get up and running fairly quickly especially as the program is largely intuitive Schematic drawing Symbols are presented in generic form in a series of twelve pre stocked symbol parts bins They include a set of virtual instruments probes and measuring tools so Tina is fine for on screen experimentation It is possible to add to and modify the content of these parts bins via an editing tool The symbol library is backed by a library of 10000 compo nent models a doubling over the previous version Mouse operation in Tina is straight forward click left to commence click right to finish click left to select an existing symbol and right to edit via a sub menu The
4. PC ENGINEERING Review subjects The first review covered Electronics Workbench version 5 12 whose maker is IIT Ltd of Canada W orkbench s UK supplier is Adept Scientific plc tel 01462 480055 Electronic Workbench s price is 199 Rod looked at CircuitM aker in the August issue This 199 package is made by MicroCode in the US and supplied by Labvolt in the UK tel 01480 300695 Subsequent reviews will cover Labcenter s Lisa which is part of Proteus IV and Pulsar and Analyser from Number One Systems which are modules from the Easy PC package 738 Has Tina s third incarnation Tina Pro been worth waiting for Rod Cooper investigates The route to simulation Ill ina is a relative newcomer to the f UK It was first reviewed in Electronics World in the September 1996 issue by Clive Ousby I recommend that you take a look at Clive s review to get a broader view of the program The original Tina program was upgraded to Tina Plus and it has now been further developed into the new Tina Pro The main differences in Tina Pro include a change to 32 bit operation a much improved schematic drawing program an expanded model library and several extra analyses This is a big leap forward by any standard The latest version 5 21 of this new program has become a useful wide ranging general purpose program The minimum system requirements are a 486DX 16Mbyte of RAM at least 15Mbyte of disk space to inst
5. Workbench would chart as Fig 4 make the learning curve gentler and but with a slightly increase its appeal to many potential users especially first time CAD users But Tina Pro would certainly suit those with even a modicum of experience in simulation The package is aimed at both the educational market as it has many features only of use in this particular field and at the design engineer Just as with other programs with an edu cational bias like Workbench and CircuitMaker there is much to attract the practical designer To Tina s credit about 1Mbyte of the educa tional features can be omitted during the installation process if you wish For engineer and educationalist alike Tina is good value for money It s 100 more than Workbench or CircuitMaker but the extra features make it well worthwhile Tina con tinues to show rapid development with an original approach and enlarged timing chart and with the glitch control set to 10 showing the relevant glitches promises to be one of the main con tenders in this market sector E September1999 ELECTRONICS WO RLD 741
6. all and Windows 95 or 98 or NT4 0 There is no Windows 3 1 version The copy of Tina Pro provided for review was on a CD and installation was straightforward Security is a little more complex than with other programs though A registration number is pro vided with the CD The owner has to contact the supplier or e mail DesignSoft and exchange this number for a unique security number This can take a while but the package can be used up to 15 times without the security key at which point the program will not run again until the number is entered The security key is specific not only to one computer but also the directory it is installed in so the program cannot be moved As an alternative some versions are dongled In practice using e mail the security key took just three days to arrive Documentation The user manual has been rewritten and now has a less academic approach than previous versions It follows the current trend of many Windows applications in being a small volume without an index or glossary giving just the bare essen tials More reliance is made on the pro gram s Help files Of the programs reviewed Tina has the least reading matter The program help files hierarchy has considerable depth but the files them selves are sometimes brief There is a set of tutorials which are more helpful especially for those new to using the Tina system These run either from the program CD when there are
7. cate yourself from most mistakes without too much trouble There is no electrical rules check to look for possible mistakes like uncon nected pins and shorts and there is no autosave feature If you want to export your net list to a pcb program you can do so in Orcad Tango PCAD Protel and Redac formats Although Tina Pro s symbol library is well stocked it is possible to add Cany T N L ae O 002 Hew UU i _ _ Ti Tii TLD TH a a i a i i su Hih otek Tras e Po your own symbols as there is a dedi cated symbol drawing section This is a good concept The symbol drawing program is started separately from the main program via the Tina start menu Drawing symbols from scratch using this editor and then implement ing them was easy You can attach Spice models to these symbols Another self contained section enables Spice macros to be added Simulation Tina Pro is described as Spice 3F5 compatible and features a native mixed mode simulator There are seven main virtual instru ments for performing analyses an oscilloscope a signal analyser a function generator a digital signal generator a logic analyser a digital multimeter and an XY plotter When expanded these instruments all have the appearance of real instru ments similar to the ones in Electronics Workbench In addition there are several other measuring tools including a power meter and impedance meter
8. power reactive power and phase This is done not through a vir tual instrument type interface but via the ac analysis nodal voltage dialogue box It is not intuitive To see the detailed readings you have to place the probe on the power meter The other instrument that caught my eye was the impedance meter This system is more direct than that in CircuitMaker It is easy to use and intuitive An example giving a graph of input impedance versus frequency of an active filter is shown in Fig 2 By using the nodal voltage probe as with the power meter you can get values for admittance and phase The oscilloscope is not restricted to two channels as it is in Workbench for example It can function like a ELECTRONICS WORLD September 1999 normal oscilloscope or in storage mode Besides the virtual instruments you can run analyses by fixing probes instruments in place and selecting the type of analysis you require from the menu system DC and AC analyses and transient and noise analyses are handled this way Where appropriate Nyquist graphs can be displayed an unusual and interesting feature at this level All these graphs can be run full screen for easy measurement A typical AC analysis run from a menu is shown in Fig 3 The above mentioned analyses can be modified from the mode menu This is a blanket system of applying temperature stepping parameter stepping worst case optimum and Monte Carlo graphing me
9. r section has a strong educational bias Faults can be set an equation editor is provided to insert formulae into the schematic and there is even an Exam mode Another interesting feature of this a foah ERER TEAR Seb aea yg PC ENGIN EERIN G Jema Jx ae E bes S e a EE E E 4 z 4 bit synchronous cascadable counter E nra s a DEME Menene m reka Genie program which is noteworthy even 1f not really connected with simulation is the availability of plug in boards to provide real time measurements from actual circuits Results can be dis played alongside the predicted results to show up any discrepancy In summary The first thing that existing Tina users will notice is how much improved the schematic drawing sec tion is compared to previous ver sions It can now be said to be pleas ant to use In the simulation section the range and scope of the basic analyses offered in Tina Pro are excellent All of the basic requirements of a simu lation program as listed in the intro duction are met In addition there are specialist features like the power meter Nyquist diagrams and sym bolic analysis not found in other products at this price level The small written manual brief Help files and the style of the pro gram give Tina Pro a medium steep learning curve I think a user manual Minan AAAA Lie comparable to that in CircuitMaker Fig 5 The same or Electronic
10. re are no complicated left plus right routines to memorise This system is carried over into the simulations Wiring up The wiring up part of the schematic editor is a big improvement on previ ous versions It is now possible to wire up symbols quickly and easily and just as quickly delete them To wire up you can either click right and choose this function or simply move the cursor to a symbol terminal when it changes to a drawing pen and off you go You can choose whether to wire manually or automatically Autowiring is not like the systems found in other programs but is more of an assisted manual method Both systems were pleasant to use Wires under construction can be deleted by reversing the track and whole wires can now be deleted by selecting them with the right mouse button and picking delete Previously they had to be deleted sec tion by section However mistakes wires ending in space for example are not automatically deleted The schematic drawing is orthogo nal It is possible to move the symbol PC ENGIN EERIN G FA T Hi ae pare rea ea es ee EFiermiza aers Pals ele Fh mir n j Edi Legere gr ed TLE Ea A ves 1 aTi Op _ Fig 1 A Tina schematic showing how the virtual instruments are wired into circuit much like Electronic canis aH Workbench top bP al and the virtual oscilloscope expanded to tale E i show the lopai controls left
11. thods to the above analyses This is a logical way to organise these analyses It is possible to obtain a Fourier series or spectrum of thd An easy and direct method is used Symbolic analysis can be per formed to obtain an expression for the response of DC AC and transient analogue simulations For a low cost simulator this is another unusual fea ture It provides an alternative view of the behaviour of analogue circuits particularly for some second order effects Other arguments for it include bet ter insight and understanding of the circuit under test In addition teach ers may regard it as useful for instructing students Figure 2 shows a typical result Digital analysis can be run step by step as well as normal mode There is no coloured wire system for clarify ing more complex circuits as in Electronic Workbench but there is a pin colouring system which gives some help on complex circuits In digital simulation there is good control over glitch threshold value Like many other simulators Tina has a fixed threshold system for showing glitches in this case the default value being 50 of the delay of the digital devices However this can be over ridden with a value set by the opera tor which makes it a much more use ful system Lowering the percentage reveals more glitches i e those with shorter duration and vice versa Again this is implemented in a way that is sim ple and easy to use The simulato
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