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Window comparator

  1. Apr 2, 2008 #1
    http://img409.imageshack.us/img409/4825/sdfsbe9.jpg [Broken]

    i am getting this error when i simulated the above circuit
    what could be wrong



    ** Creating circuit file "window-SCHEMATIC1-window.sim.cir"

    * Local Libraries :
    * From [PSPICE NETLIST] section of C:\Program Files\OrcadLite\PSpice\PSpice.ini file:
    .lib "nom.lib"

    *Analysis directives:
    .DC LIN V_V1 1 10 1
    .PROBE V(*) I(*) W(*) D(*) NOISE(*)
    .INC ".\window-SCHEMATIC1.net"

    **** INCLUDING window-SCHEMATIC1.net ****
    * source WINDOW
    V_V2 N01792 0 1V
    R_R3 N01792 N01819 4.7k
    V_V3 N04475 0 15V
    R_R4 0 N01599 4.7k
    V_V4 0 N04302 15V
    R_R5 N04475 N04655 4.7k
    R_R7 N01692 N01792 4.7k
    X_U1 N01819 N01599 N04475 N04302 N04655 0 LM311
    R_R8 N01904 N01536 4.7k
    R_R9 N01904 0 4.7k
    R_R6 N01692 N01645 4.7k
    X_U2 N01692 N01904 N04475 N04302 N04655 0 LM311
    V_V1 N01536 0 6V
    R_R1 N01536 N01819 4.7k
    V_Vin N01645 0 1V
    R_R2 N01645 N01599 4.7k

    **** RESUMING window-SCHEMATIC1-window.sim.cir ****

    ERROR -- Subcircuit LM311 used by X_U1 is undefined
    ERROR -- Subcircuit LM311 used by X_U2 is undefined
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Apr 2, 2008 #2


    User Avatar

    Staff: Mentor

    Thread moved to Homework Help.

    The error says that the LM311 subcircuit is not defined. Sounds like there is some issue with the library. Did you put the LM311 parts into the schematic yourself from your library, or did you get the circuit from someplace else, and you don't have the LM311 in your PC's installation of the simulator?
  4. Apr 2, 2008 #3
    lm311 is in the library. under opamp. i dont know why it says undefined.

    i am trying to get the vtl and vth.. in the simulation which is vtl = 5v
    and vth = 7v..
    Last edited: Apr 2, 2008
  5. Apr 2, 2008 #4


    User Avatar

    Staff: Mentor

    Try deleting them and re-inserting them into the schematic.
  6. Apr 2, 2008 #5
    i have tried deleting it and reinserting them several times it doesn't work.. same error
  7. Apr 2, 2008 #6


    User Avatar

    Staff: Mentor

    Can you try using a different comparator instead of the LM311? Do you get the same error? You might try PSPICE's support pages to see if it has some entries for that error. Could be a library file directory placement problem or something.
  8. Apr 2, 2008 #7
    lm111 does give a output but i think it is wrong... since it does not give me a square wave..

    and 5 volts vtl and 7 volts vth... i think its wrong
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