I designed a simple [electronic circuit][1] that can control the motion of 4 DC motors using Raspberry Pi 3. I want to be able to check the voltages across the circuit using multiple voltage probes and similarly probe the current but I am unable to do so owing to the following: 1.) I am using the [MAX471 Voltage current sensor][2] which does not exist in database. I made my own schematic but it complains that there is no package assigned. How do I make a package for this ? 2.) My errors look like this: Circuit: good* no system model for 5a ubec, you can create a model by yourselfuntitled Error on line 3 : stwist stwist_1 stwist_5 prp_33 prp_31 stwist_5 prp_29 sw_stwist off Unable to find definition of model stwist_5 - default assumed unknown parameter (prp_29) Error on line 5 : slinear umd_7 slinear_5 umd_5 umd_10 slinear_5 slinear_6 sw_slinear off Unable to find definition of model slinear_5 - default assumed unknown parameter (slinear_6) Error on line 11 : jp1 nonet nonet nonet nonet 5a ubec Unable to find definition of model nonet - default assumed unknown parameter (ubec) errors/warnings in your design, please fix them if you need errors/warnings in your design, please fix them if you need. Doing analysis at TEMP = 27.000000 and TNOM = 27.000000 Warning: r1: resistance to low, set to 1 mOhm Warning: r2: resistance to low, set to 1 mOhm Warning: r3: resistance to low, set to 1 mOhm Warning: r4: resistance to low, set to 1 mOhm Warning: singular matrix: check nodes umd_7 and umd_7 Note: Starting dynamic gmin stepping Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Warning: singular matrix: check nodes umd_7 and umd_7 Warning: Dynamic gmin stepping failed Note: Starting source stepping Warning: singular matrix: check nodes umd_7 and umd_7 Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful gmin step Note: One successful source step Warning: singular matrix: check nodes umd_7 and umd_7 Warning: singular matrix: check nodes umd_7 and umd_7 Warning: source stepping failed Transient solution failed - Last Node Voltages ------------------ Node Last Voltage Previous Iter ---- ------------ ------------- volprobe1 0 0 stwist_1 0 0 stwist_5 0 0 prp_33 0 0 prp_31 0 0 umd_7 0 0 slinear_5 0 0 umd_5 0 0 umd_10 0 0 r4_1 0 0 r4_2 0 0 r3_1 0 0 r3_2 0 0 r2_1 0 0 r2_2 0 0 r1_1 0 0 nonet 0 0 vbattery#branch 0 0 doAnalyses: iteration limit reached tran simulation(s) aborted Error(parse.c--checkvalid): volprobe1: no such vector. ngspice-26 done The DPDT switches labeled as "twist" and "linear" are for controlling the motor directions which correspond to errors in Line 3 and 5. The last error is in UBEC. 3.) Why do I see all voltages as ZERO ? 4.) In order to probe currents, if I add built-in ammeters, then I get an error stating, system model does not exist. Is this warning to be ignored or is there a way to add this model ? 5.) To run the circuit and get the current and voltage readings I am doing simply Ctrl+R. Is there a script I need to write or is this sufficient ? 6.) I see the voltages per iteration are shown in outputs but is there a way to also print the current through the ammeters (once I re-add) them ? 7.) If I were to convert this to a PCB layout, what should I do for the custom schematic of the MAX471 sensor? There is no pcb layer available for it online. Please advise. [1]: https://easyeda.com/3230056901a94c98b866a0b588de7245/Rusti_V2_0-90b00465f23444e6acf97259f762b5f8 [2]: http://www.uctronics.com/max471-voltage-current-volt-amp-test-sensor-module-for-arduino.html