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 Help regarding the error "Time step too small in OrCAD PSpice"  

Last post Mon, Aug 22 2011 6:36 AM by alokt. 1 replies.
Started by shilpakhetan 19 Aug 2011 05:21 AM. Topic has 1 replies and 1497 views
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  • Fri, Aug 19 2011 5:21 AM

    Help regarding the error "Time step too small in OrCAD PSpice" Reply

     Hi all,

       I am in a problem and need help urgently. I am trying to simulate time varying EPR (Equivalent Parallel Resistance) which is a part of SuperCapacitor model in PSpice. The netlist is:

    .SUBCKT EPR + -   
    .PARAM Eepr=2.8085V Co=100F
    .FUNC EPR(time) {TABLE(time,
    +60s, 1.3K, 180s, 2.1K, 360s, 2.8K, 480s, 3K, 600s, 3.44K)}
    Eepr + - value= {(Eepr*exp(-time/(Co*EPR(time))))}
    .MODEL EPR RES (R=1.0 TC1=0.0 TC2=0.0 TCE=0.0 DEV/GAUSS 1% LOT/UNIFORM 5%)
    .ENDS

    and the simulation file shows an error:

     Time step =  573.4E-12 is too small in Transient Analysis at

    Unable to finish transient analysis

    The netlist of SuperCapacitor model is:

    * source 100F_EPR_3
    X_U1         0 N07132 EPR
    C_C         N07132 0  94.22 
    R_ESR         N00027 N06933  18m 
    I_I1         0 N00027 
    +PWL 0 0 1 1 264 1 265 0 865 0 866 -1 1123 -1 1124 0 1200 0
    S_S1         N00027 N01143 N00027 0 _S1
    RS_S1        N00027 0 1G
    .MODEL        _S1 VSWITCH Roff=1e6 Ron=1.0 Voff=2.82V Von=2.8V
    R_R1         N01143 0  1.3K 
    R_Rp         N06933 N07132  10m 
    C_C1         N06933 N07132  7.25 

    I have no clue why this is happening. I tried to change the RELTOL, VNTOL, ABSTOL, ITL1 and ITL4 parameters in .OPTIONS settings but it did'nt help. Any help will be highly appreciated.

    Thanks and Regards,

    Shilpa.

     

     

    • Post Points: 20
  • Mon, Aug 22 2011 6:36 AM

    • alokt
    • Top 25 Contributor
    • Joined on Fri, Aug 22 2008
    • Noida, Uttar Pradesh
    • Posts 241
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    Re: Help regarding the error "Time step too small in OrCAD PSpice" Reply

    I am able to simulate the above circuit without any error. I have done the simulation for 600Sec and I am using 16.5 version.

    Looking at your circuit: you have chosen too narrow range for voltage controlling switch _S1, You should relax this if such tight range is not needed. 

    Below is the simulation result at my end:


    **** 08/22/11 19:03:08 ****** PSpice 16.5.0 (April 2011) ****** ID# 0 ********

     ***


     ****     CIRCUIT DESCRIPTION


    ******************************************************************************




    * source 100F_EPR_3
    X_U1         0 N07132 EPR
    C_C         N07132 0  94.22 
    R_ESR         N00027 N06933  18m 
    I_I1         0 N00027 
    +PWL 0 0 1 1 264 1 265 0 865 0 866 -1 1123 -1 1124 0 1200 0
    S_S1         N00027 N01143 N00027 0 _S1
    RS_S1        N00027 0 1G
    .MODEL        _S1 VSWITCH Roff=1e6 Ron=1.0 Voff=2.82V Von=2.8V
    R_R1         N01143 0  1.3K 
    R_Rp         N06933 N07132  10m 
    C_C1         N06933 N07132  7.25
    .SUBCKT EPR + -   
    .PARAM Eepr=2.8085V Co=100F
    .FUNC EPR(time) {TABLE(time,
    +60s, 1.3K, 180s, 2.1K, 360s, 2.8K, 480s, 3K, 600s, 3.44K)}
    Eepr + - value= {(Eepr*exp(-time/(Co*EPR(time))))}
    .MODEL EPR RES (R=1.0 TC1=0.0 TC2=0.0 TCE=0.0 DEV/GAUSS 1% LOT/UNIFORM 5%)
    .ENDS

    .tran 1u 600
    .probe
    .end

    **** 08/22/11 19:03:08 ****** PSpice 16.5.0 (April 2011) ****** ID# 0 ********

     ***


     ****     Resistor MODEL PARAMETERS


    ******************************************************************************




                   X_U1.EPR       
               R    1           


    **** 08/22/11 19:03:08 ****** PSpice 16.5.0 (April 2011) ****** ID# 0 ********

     ***


     ****     Voltage Controlled Switch MODEL PARAMETERS


    ******************************************************************************




                   _S1            
             RON    1           
            ROFF    1.000000E+06
             VON    2.8         
            VOFF    2.82        


    **** 08/22/11 19:03:08 ****** PSpice 16.5.0 (April 2011) ****** ID# 0 ********

     ***


     ****     INITIAL TRANSIENT SOLUTION       TEMPERATURE =   27.000 DEG C


    ******************************************************************************



     NODE   VOLTAGE     NODE   VOLTAGE     NODE   VOLTAGE     NODE   VOLTAGE


    (N00027)   -2.8084 (N01143)   -2.8063 (N06933)   -2.8085 (N07132)   -2.8085




        VOLTAGE SOURCE CURRENTS
        NAME         CURRENT


        TOTAL POWER DISSIPATION   0.00E+00  WATTS



              JOB CONCLUDED

    **** 08/22/11 19:03:08 ****** PSpice 16.5.0 (April 2011) ****** ID# 0 ********

     ***


     ****     JOB STATISTICS SUMMARY


    ******************************************************************************



      Total job time (using Solver 1)   =         .09

     

    • Post Points: 5
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Started by shilpakhetan at 19 Aug 2011 05:21 AM. Topic has 1 replies.