docs/wiki/geda-circuit_simulation_improvements.html

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  13 <p>
  14 <em>Translations of this page are also available in the following languages:</em> <a href="geda-circuit_simulation_improvements.ru.html" class="wikilink1" title="geda-circuit_simulation_improvements.ru.html">Русский</a>.
  15 </p>
  16
  17 <h1 class="sectionedit1" id="circuit_simulation_improvements_in_gschem">Circuit simulation improvements in gschem</h1>
  18 <div class="level1">
  19
  20 </div>
  21 <!-- EDIT1 SECTION "Circuit simulation improvements in gschem" [134-190] -->
  22 <h2 class="sectionedit2" id="rationale">Rationale</h2>
  23 <div class="level2">
  24
  25 <p>
  26 Using gschem as a circuit simulation (ngspice or gnucap) frontend is not easy for novice users. A new user would like to do the following things inside gschem:
  27 </p>
  28 <ul>
  29 <li class="level1"><div class="li"> specify what kinds of simulations should be run</div>
  30 </li>
  31 <li class="level1"><div class="li"> specify which voltages and currents should be plotted</div>
  32 </li>
  33 <li class="level1"><div class="li"> start the simulation</div>
  34 </li>
  35 </ul>
  36
  37 <p>
  38 The simulation runs and the postprocessing may be in an external program that is triggered by IPC.
  39 </p>
  40
  41 <p>
  42 There are some graphical frontends around but they can&#039;t solve all of the above problems
  43 </p>
  44 <ul>
  45 <li class="level1"><div class="li"> <a href="http://www.geda.seul.org/tools/gspiceui/index.html" class="urlextern" title="http://www.geda.seul.org/tools/gspiceui/index.html" rel="nofollow">gspiceui</a></div>
  46 </li>
  47 <li class="level1"><div class="li"> <a href="http://www.comefly.us/" class="urlextern" title="http://www.comefly.us/" rel="nofollow">kjwaves</a></div>
  48 </li>
  49 <li class="level1"><div class="li"> <a href="http://easy-spice.sourceforge.net/" class="urlextern" title="http://easy-spice.sourceforge.net/" rel="nofollow">easyspice</a></div>
  50 </li>
  51 </ul>
  52
  53 <p>
  54 All frontends have the problem that you can not point to the net you&#039;d like to see. You need to know the netname of the node.
  55 </p>
  56
  57 </div>
  58 <!-- EDIT2 SECTION "Rationale" [191-987] -->
  59 <h2 class="sectionedit3" id="draft">Draft</h2>
  60 <div class="level2">
  61
  62 <p>
  63 Let&#039;s assume we only want to make tiny changes to gschem and libgeda so that we can at least set some probes and ran a simulation.
  64 </p>
  65
  66 </div>
  67 <!-- EDIT3 SECTION "Draft" [988-1137] -->
  68 <h3 class="sectionedit4" id="the_probes">The probes</h3>
  69 <div class="level3">
  70
  71 <p>
  72 <strong>Current probes</strong> can be ordinary dc voltage sources with 0V. The easy way to insert that probe would be a symbol with two pins like an normal ampere meter.
  73 If we&#039;d like to set a current probe to an end of a pin we need a netlister that detects that current probe and replaces it with our “ampere meter”.
  74 If we use a voltage source as an ampere meter the netlister does not need to know the netnames inside the schematic. All 0V voltage sources with a special device name are current probes.
  75 </p>
  76
  77 <p>
  78 <strong>Voltage probes</strong> may be current sources with 0A. The second pin of the current source is tied to GND with a net attribute. Thus again the netlister does not need to know the netnames as it can use that net that is connected with that special current sources.
  79 Like above a voltage source could be a special (graphical) symbol that is detected by a netlister.
  80 </p>
  81
  82 </div>
  83 <!-- EDIT4 SECTION "The probes" [1138-2013] -->
  84 <h3 class="sectionedit5" id="voltage_and_current_sources">Voltage and current sources</h3>
  85 <div class="level3">
  86
  87 <p>
  88 Specifying the parameters of sources is not that easy. Currently they are stored inside the “value” attribute of the symbol.
  89 e.g. “value=pulse 0 1 10n 10n 100n 1u 2u”. These settings needs to match the spice attributes “pulse(V1 V2 TD TR TF PW PER)”.
  90 </p>
  91
  92 <p>
  93 A dialog would be nice that prompts the user for the named attributes and not only for the value string.
  94 </p>
  95
  96 <p>
  97 A modified edit attribute (<kbd>E</kbd><kbd>E</kbd>) command could take care of voltage and current source devices and trigger a different property dialog for that sources. Currently the multiattrib edit dialog is triggered.
  98 </p>
  99
 100 </div>
 101 <!-- EDIT5 SECTION "Voltage and current sources" [2014-2635] -->
 102 <h3 class="sectionedit6" id="the_simulations">The simulations</h3>
 103 <div class="level3">
 104
 105 <p>
 106 How can we store a simulation inside gschem.
 107 </p>
 108
 109 <p>
 110 To store one simulation we can use a symbol with the device name “SIMULATION”.
 111 All options that define one simulation are stored as attributes attached to that object.
 112 </p>
 113 <ul>
 114 <li class="level1"><div class="li"> kind of simulation (dc, ac, tran, …)</div>
 115 </li>
 116 <li class="level1"><div class="li"> simulator options</div>
 117 </li>
 118 <li class="level1"><div class="li"> the simulator? (can we run the same circuit with two simulators in one step?)</div>
 119 </li>
 120 <li class="level1"><div class="li"> simulation parameters (global parameters, temperature, …)</div>
 121 </li>
 122 </ul>
 123 <pre class="code">v 20061020 1
 124 C 41500 49200 1 0 0 spice-directive-1.sym
 125 {
 126 device=spice_simulation_block
 127 refdes=A1
 128 simulation_name=random name
 129 simulation_active=1
 130 simulation_type=DC 0V 1V 0.1V
 131 parametric_simulation1=V1 lin 0 5 0.1
 132 parametric_simulation2=R1.value lin 10k 100k 10k
 133 option_TNOM=100 Deg
 134 option_ABSTOL=1e-3
 135 global_param1=???
 136 global_param2=???
 137 }</pre>
 138
 139 <p>
 140 There may be many simulation objects inside a single schematic.
 141 </p>
 142
 143 <p>
 144 To store additional libraries we can either use an include card or using a “LIBRARY” symbol that contains all libraries either as:
 145 </p>
 146 <ul>
 147 <li class="level1"><div class="li"> a multiline attribute</div>
 148 </li>
 149 <li class="level1"><div class="li"> multiple attached library attributes to the LIBRARY symbol</div>
 150 </li>
 151 </ul>
 152
 153 <p>
 154 There should be a distinction between global, user and local libs.
 155 global and user libs may be specified by a gafrc or a new spicerc configuration file.
 156 </p>
 157
 158 </div>
 159 <!-- EDIT6 SECTION "The simulations" [2636-3883] -->
 160 <h3 class="sectionedit7" id="creating_a_simulation_dialog_inside_gschem">Creating a simulation dialog inside gschem</h3>
 161 <div class="level3">
 162
 163 <p>
 164 Lets assume anything we need to add simulation support to gschem is a single dialog.
 165 </p>
 166 <ul>
 167 <li class="level1"><div class="li"> It would have a list of simulations (listview with enable/disable buttons and simulation names)</div>
 168 </li>
 169 <li class="level1"><div class="li"> It would have some icons to add the probes.</div>
 170 </li>
 171 <li class="level1"><div class="li"> It may have buttons for the most common symbols: resistor, capacitor, inductor, diode, … [R,C,L,D,M,E,F,G,H..]</div>
 172 </li>
 173 <li class="level1"><div class="li"> It would have some dialog elements to do the spice settings</div>
 174 </li>
 175 <li class="level1"><div class="li"> It would have a simulate and a close button</div>
 176 </li>
 177 <li class="level1"><div class="li"> Some additional buttons like: Copy simulation, Remove simulation, general options…</div>
 178 </li>
 179 </ul>
 180
 181 <p>
 182 When creating that dialog all simulation objects are collected into the simulation list (listview with enable/disable checkbutton)
 183 </p>
 184
 185 <p>
 186 When changing the settings the attributes of the associated simulation object are changed.
 187 </p>
 188
 189 </div>
 190 <!-- EDIT7 SECTION "Creating a simulation dialog inside gschem" [3884-4714] -->
 191 <h3 class="sectionedit8" id="the_option_dialog">The option dialog</h3>
 192 <div class="level3">
 193
 194 <p>
 195 What kind of options do we need for that dialog? And Why?
 196 </p>
 197
 198 <p>
 199 The probes that we have placed can be used to tell the simulator the variables that we like to save or tell the plotting application which plots we&#039;d like to see. This is something completely different, we need an option for that:
 200 </p>
 201 <ul>
 202 <li class="level1"><div class="li"> plot all marks and only save the corresponding node voltages</div>
 203 </li>
 204 <li class="level1"><div class="li"> plot all marks but save all node voltages and currents (through voltage sources)</div>
 205 </li>
 206 <li class="level1"><div class="li"> only save voltage nodes of the current schematic level or store subcircuit node voltages, too.</div>
 207 </li>
 208 </ul>
 209
 210 </div>
 211 <!-- EDIT8 SECTION "The option dialog" [4715-5282] -->
 212 <h3 class="sectionedit9" id="invoking_the_simulation">Invoking the simulation</h3>
 213 <div class="level3">
 214
 215 <p>
 216 The simulation button of the dialog should lead to the following actions:
 217 </p>
 218 <ul>
 219 <li class="level1"><div class="li"> save the schematic (ask the user or use a temporary file?)</div>
 220 </li>
 221 <li class="level1"><div class="li"> create a netlist using gnetlist</div>
 222 </li>
 223 <li class="level1"><div class="li"> create simulation files and include the netlist (can this be done with gnetlist too?)</div>
 224 </li>
 225 <li class="level1"><div class="li"> execute the simulation startup script (guile, sh, …)</div>
 226 </li>
 227 </ul>
 228
 229 <p>
 230 That startup script may even call a scheduler that can take lots of large simulations.
 231 </p>
 232
 233 </div>
 234 <!-- EDIT9 SECTION "Invoking the simulation" [5283-5727] -->
 235 <h2 class="sectionedit10" id="appendix">Appendix</h2>
 236 <div class="level2">
 237
 238 </div>
 239 <!-- EDIT10 SECTION "Appendix" [5728-5748] -->
 240 <h3 class="sectionedit11" id="a_voltage_probe_symbol_draft">A voltage probe symbol (draft)</h3>
 241 <div class="level3">
 242 <dl class="code">
 243 <dt><a href="/./_export/code/:geda:circuit_simulation_improvements.txt?codeblock=1" title="Download Snippet" class="mediafile mf_sym">voltage_probe.sym</a></dt>
 244 <dd><pre class="code gschem-symbol">v 20061020 1
 245 P 0 0 200 200 1 0 0
 246 {
 247 T 100 0 5 10 0 1 0 0 1
 248 pintype=pas
 249 T 0 100 5 10 0 1 0 0 1
 250 pinseq=1
 251 T 0 100 5 10 0 1 0 0 1
 252 pinnumber=1
 253 T 0 100 5 10 0 1 0 0 1
 254 pinlabel=1
 255 }
 256 V 300 300 150 3 10 0 0 -1 -1 0 -1 -1 -1 -1 -1
 257 L 300 200 240 360 3 10 0 0 -1 -1
 258 L 300 200 360 360 3 10 0 0 -1 -1
 259 T 0 500 9 10 0 0 0 0 1
 260 device=VOLTAGE_PROBE
 261 T 200 50 9 6 1 1 0 0 1
 262 refdes=I_VP?
 263 T 0 700 9 10 0 0 0 0 1
 264 net=GND:2
 265 T 0 900 9 10 0 0 0 0 1
 266 value=DC 0A</pre>
 267 </dd></dl>
 268
 269 </div>
 270 <!-- EDIT11 SECTION "A voltage probe symbol (draft)" [5749-6270] -->
 271 <h3 class="sectionedit12" id="a_current_probe_symbol_draft">A current probe symbol (draft)</h3>
 272 <div class="level3">
 273 <dl class="code">
 274 <dt><a href="/./_export/code/:geda:circuit_simulation_improvements.txt?codeblock=2" title="Download Snippet" class="mediafile mf_sym">current_probe.sym</a></dt>
 275 <dd><pre class="code gschem-symbol">v 20061020 1
 276 P 0 200 150 200 1 0 0
 277 {
 278 T -150 50 5 10 0 1 0 0 1
 279 pintype=pas
 280 T 50 250 5 10 0 1 0 0 1
 281 pinseq=1
 282 T 50 250 5 10 0 1 0 0 1
 283 pinnumber=1
 284 T 50 250 5 10 0 1 0 0 1
 285 pinlabel=1
 286 }
 287 V 300 200 150 3 10 0 0 -1 -1 0 -1 -1 -1 -1 -1
 288 L 300 300 380 140 3 10 0 0 -1 -1
 289 L 300 300 220 140 3 10 0 0 -1 -1
 290 T 0 500 9 10 0 0 0 0 1
 291 device=CURRENT_PROBE
 292 T 200 370 9 6 1 1 0 0 1
 293 refdes=V_IP?
 294 P 600 200 450 200 1 0 0
 295 {
 296 T 500 50 5 10 0 1 0 0 1
 297 pintype=pas
 298 T 500 250 5 10 0 1 0 0 1
 299 pinseq=2
 300 T 500 250 5 10 0 1 0 0 1
 301 pinnumber=2
 302 T 500 250 5 10 0 1 0 0 1
 303 pinlabel=2
 304 }
 305 L 240 180 360 180 3 10 0 0 -1 -1
 306 T 0 700 9 10 0 0 0 0 1
 307 value=DC 0V</pre>
 308 </dd></dl>
 309
 310 </div>
 311 <!-- EDIT12 SECTION "A current probe symbol (draft)" [6271-6971] -->
 312 <h3 class="sectionedit13" id="another_current_probe_symbol_used_by_kurt_peters">Another current probe symbol used by Kurt Peters</h3>
 313 <div class="level3">
 314 <dl class="code">
 315 <dt><a href="/./_export/code/:geda:circuit_simulation_improvements.txt?codeblock=3" title="Download Snippet" class="mediafile mf_sym">ammeter.sym</a></dt>
 316 <dd><pre class="code gschem-symbol">v 20061020 1
 317 T 700 650 8 10 1 1 0 0 1
 318 refdes=VAM?
 319 T 700 850 5 10 1 1 0 0 1
 320 device=Ammeter
 321 T 700 1050 5 10 0 0 0 0 1
 322 footprint=none
 323 T 700 1250 5 10 0 0 0 0 1
 324 numslots=0
 325 T 700 1450 5 10 0 0 0 0 1
 326 description=ammeter for spice
 327 P 300 1200 300 900 1 0 0
 328 {
 329 T 350 1000 5 8 1 1 0 0 1
 330 pinnumber=1
 331 T 350 1000 5 8 0 1 0 2 1
 332 pinseq=1
 333 T 400 850 9 8 1 1 0 5 1
 334 pinlabel=+
 335 T 300 700 5 8 0 1 0 5 1
 336 pintype=pwr
 337 }
 338 P 300 0 300 300 1 0 0
 339 {
 340 T 350 100 5 8 1 1 0 0 1
 341 pinnumber=2
 342 T 350 100 5 8 0 1 0 2 1
 343 pinseq=2
 344 T 300 500 5 8 0 1 0 3 1
 345 pintype=pwr
 346 T 300 300 5 10 1 1 0 0 1
 347 pinlabel=-
 348 }
 349 L 300 400 400 500 3 0 0 0 -1 -1
 350 L 200 500 300 400 3 0 0 0 -1 -1
 351 T 700 450 5 10 0 1 0 0 1
 352 value=DC 0V
 353 L 300 400 300 800 3 0 0 0 -1 -1
 354 L 100 800 500 400 3 0 0 0 -1 -1
 355 B 0 300 600 600 3 0 0 0 -1 -1 0 -1 -1 -1 -1 -1
 356 L 200 800 100 800 3 0 0 0 -1 -1
 357 L 100 700 100 800 3 0 0 0 -1 -1</pre>
 358 </dd></dl>
 359
 360 </div>
 361 <!-- EDIT13 SECTION "Another current probe symbol used by Kurt Peters" [6972-] --></body>
 362 </html>