Nominals Changing

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  • Nominals Changing

    Every once in a while I will measure, in this case a line, something with a known nominal value. When I ask for the location of that feature, the nominal has changed.

    I'm sure there's a reason for this, I just can't find it. See lin1 below.

    LIN1 =FEAT/LINE,CARTESIAN,UNBOUNDED
    THEO/<-1.1664,-0.683,-0.3181>,<0.9999999,-0.000325,0>
    ACTL/<-1.1664,-0.6829,-0.3181>,<0.9999999,-0.000325,0>
    MEAS/LINE,6,ZPLUS
    HIT/BASIC,NORMAL,<-1.1664,-0.6833,-0.3177>,<-0.000325,-0.9999999,0>,<-1.1664,-0.6833,-0.3177>,USE THEO=YES
    HIT/BASIC,NORMAL,<-0.6192,-0.6829,-0.3179>,<-0.000325,-0.9999999,0>,<-0.6192,-0.6829,-0.3179>,USE THEO=YES
    HIT/BASIC,NORMAL,<-0.0832,-0.683,-0.3181>,<-0.000325,-0.9999999,0>,<-0.0832,-0.683,-0.3181>,USE THEO=YES
    HIT/BASIC,NORMAL,<0.4556,-0.6833,-0.3182>,<-0.000325,-0.9999999,0>,<0.4556,-0.6833,-0.3182>,USE THEO=YES
    HIT/BASIC,NORMAL,<0.9634,-0.6838,-0.3184>,<-0.000325,-0.9999999,0>,<0.9634,-0.6838,-0.3184>,USE THEO=YES
    HIT/BASIC,NORMAL,<1.2537,-0.6838,-0.3185>,<-0.000325,-0.9999999,0>,<1.2537,-0.6838,-0.3185>,USE THEO=YES
    ENDMEAS/

    DIM LOC12= LOCATION OF LINE LIN1 UNITS=IN ,$
    GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH HALF ANGLE=NO
    AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
    Y -0.6834
    0.0005 0.0005 -0.6833 0.0001 0.0000 ----#----
    END OF DIMENSION LOC12
    LIN2 =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
    THEO/<-0.755,0.6338,-0.235>,<1,0,0>
    ACTL/<-0.7537,0.6343,-0.2352>,<1,0,0>
    CONSTR/LINE,BF,2D,CIR4,CIR5,,
    OUTLIER_REMOVAL/OFF,3
    FILTER/OFF,WAVELENGTH=0
    COMMENT/REPT,
    PARALLEL OF FLAT @ .683 AND DOWEL PIN HOLES #1 & #2
    DIM PARL1= PARALLELISM OF LINE LIN1,RFS TO LINE LIN2,RFS EXTENDLENGTH=0.0000 UNITS=IN ,$
    GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH
    AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
    M 0.0000 0.0050 0.0000 0.0010 0.0010 0.0000 -#-------
    TIP/T1A7.5B180, SHANKIJK=0.0041, -0.1301, 0.9915, ANGLE=-178.3216
    WORKPLANE/YMINUS
    PLN4 =FEAT/PLANE,CARTESIAN,TRIANGLE
    THEO/<0.0163,-0.683,-0.5376>,<-0.0002706,-0.9999997,0.0007295>
    ACTL/<0.0163,-0.6836,-0.5376>,<-0.0002706,-0.9999997,0.0007295>
    MEAS/PLANE,13
    HIT/BASIC,NORMAL,<-1.1736,-0.6835,-0.8124>,<-0.0002706,-0.9999997,0.0007295>,<-1.1736,-0.6835,-0.8124>,USE THEO=YES
    HIT/BASIC,NORMAL,<-0.553,-0.6835,-0.8126>,<-0.0002706,-0.9999997,0.0007295>,<-0.553,-0.6835,-0.8126>,USE THEO=YES
    HIT/BASIC,NORMAL,<0.0315,-0.6837,-0.8128>,<-0.0002706,-0.9999997,0.0007295>,<0.0315,-0.6837,-0.8128>,USE THEO=YES
    HIT/BASIC,NORMAL,<0.6048,-0.6837,-0.813>,<-0.0002706,-0.9999997,0.0007295>,<0.6048,-0.6837,-0.813>,USE THEO=YES
    HIT/BASIC,NORMAL,<1.1688,-0.6843,-0.8132>,<-0.0002706,-0.9999997,0.0007295>,<1.1688,-0.6843,-0.8132>,USE THEO=YES
    HIT/BASIC,NORMAL,<1.169,-0.684,-0.5246>,<-0.0002706,-0.9999997,0.0007295>,<1.169,-0.684,-0.5246>,USE THEO=YES
    HIT/BASIC,NORMAL,<0.1022,-0.6837,-0.5243>,<-0.0002706,-0.9999997,0.0007295>,<0.1022,-0.6837,-0.5243>,USE THEO=YES
    HIT/BASIC,NORMAL,<-1.2736,-0.6835,-0.5238>,<-0.0002706,-0.9999997,0.0007295>,<-1.2736,-0.6835,-0.5238>,USE THEO=YES
    HIT/BASIC,NORMAL,<-1.2041,-0.6831,-0.27>,<-0.0002706,-0.9999997,0.0007295>,<-1.2041,-0.6831,-0.27>,USE THEO=YES
    HIT/BASIC,NORMAL,<-0.5116,-0.6831,-0.2703>,<-0.0002706,-0.9999997,0.0007295>,<-0.5116,-0.6831,-0.2703>,USE THEO=YES
    HIT/BASIC,NORMAL,<0.0786,-0.6833,-0.2705>,<-0.0002706,-0.9999997,0.0007295>,<0.0786,-0.6833,-0.2705>,USE THEO=YES
    HIT/BASIC,NORMAL,<0.6125,-0.6835,-0.2706>,<-0.0002706,-0.9999997,0.0007295>,<0.6125,-0.6835,-0.2706>,USE THEO=YES
    HIT/BASIC,NORMAL,<1.1602,-0.6838,-0.2708>,<-0.0002706,-0.9999997,0.0007295>,<1.1602,-0.6838,-0.2708>,USE THEO=YES
    ENDMEAS/
    DIM LOC13= LOCATION OF PLANE PLN4 UNITS=IN ,$
    GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH HALF ANGLE=NO
    AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
    Y -0.6830 0.0005 0.0005 -0.6836 -0.0006 0.0001 <--------
    END OF DIMENSION LOC13
    "

  • #2
    If you add all of your hit targets together and divide by 6, the result is -0.68335 which is getting rounded up to give the -0.6834 shown.
    You can make your nominals a mathematical expression to keep them from changing (ie. -0.683+0 or -0.683*1)
    153010 Global Advantage w/ LSPX1H_T Analog Probe
    7107 Global Classic TP20
    2019R1 SP1 CAD++

    Comment


    • #3
      Instead of forcing your nominal value with a mathematical expression, fix all of your nominal values. Fix your hit target Y values so they all match the feature nominal and your hit vectors should be <0, -1, 0>. Your feature nominal vector should be <1, 0, 0>.

      Comment


      • #4
        Originally posted by CMMMAN58 View Post
        Every once in a while I will measure, in this case a line, something with a known nominal value. When I ask for the location of that feature, the nominal has changed.

        I'm sure there's a reason for this, I just can't find it. See lin1 below.

        LIN1 =FEAT/LINE,CARTESIAN,UNBOUNDED
        THEO/<-1.1664,-0.683,-0.3181>,<0.9999999,-0.000325,0>
        ACTL/<-1.1664,-0.6829,-0.3181>,<0.9999999,-0.000325,0>
        MEAS/LINE,6,ZPLUS
        HIT/BASIC,NORMAL,<-1.1664,-0.6833,-0.3177>,<-0.000325,-0.9999999,0>,<-1.1664,-0.6833,-0.3177>,USE THEO=YES
        HIT/BASIC,NORMAL,<-0.6192,-0.6829,-0.3179>,<-0.000325,-0.9999999,0>,<-0.6192,-0.6829,-0.3179>,USE THEO=YES
        HIT/BASIC,NORMAL,<-0.0832,-0.683,-0.3181>,<-0.000325,-0.9999999,0>,<-0.0832,-0.683,-0.3181>,USE THEO=YES
        HIT/BASIC,NORMAL,<0.4556,-0.6833,-0.3182>,<-0.000325,-0.9999999,0>,<0.4556,-0.6833,-0.3182>,USE THEO=YES
        HIT/BASIC,NORMAL,<0.9634,-0.6838,-0.3184>,<-0.000325,-0.9999999,0>,<0.9634,-0.6838,-0.3184>,USE THEO=YES
        HIT/BASIC,NORMAL,<1.2537,-0.6838,-0.3185>,<-0.000325,-0.9999999,0>,<1.2537,-0.6838,-0.3185>,USE THEO=YES
        ENDMEAS/

        DIM LOC12= LOCATION OF LINE LIN1 UNITS=IN ,$
        GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH HALF ANGLE=NO
        AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
        Y -0.6834
        0.0005 0.0005 -0.6833 0.0001 0.0000 ----#----
        END OF DIMENSION LOC12
        LIN2 =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
        THEO/<-0.755,0.6338,-0.235>,<1,0,0>
        ACTL/<-0.7537,0.6343,-0.2352>,<1,0,0>
        CONSTR/LINE,BF,2D,CIR4,CIR5,,
        OUTLIER_REMOVAL/OFF,3
        FILTER/OFF,WAVELENGTH=0
        COMMENT/REPT,
        PARALLEL OF FLAT @ .683 AND DOWEL PIN HOLES #1 & #2
        DIM PARL1= PARALLELISM OF LINE LIN1,RFS TO LINE LIN2,RFS EXTENDLENGTH=0.0000 UNITS=IN ,$
        GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH
        AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
        M 0.0000 0.0050 0.0000 0.0010 0.0010 0.0000 -#-------
        TIP/T1A7.5B180, SHANKIJK=0.0041, -0.1301, 0.9915, ANGLE=-178.3216
        WORKPLANE/YMINUS
        PLN4 =FEAT/PLANE,CARTESIAN,TRIANGLE
        THEO/<0.0163,-0.683,-0.5376>,<0,-1,0>
        ACTL/<0.0163,-0.6836,-0.5376>,<-0.0002706,-0.9999997,0.0007295>
        MEAS/PLANE,13
        HIT/BASIC,NORMAL,<-1.1736,-0.683,-0.8124>,<0,-1,0>,<-1.1736,-0.6835,-0.8124>,USE THEO=YES
        HIT/BASIC,NORMAL,<-0.553,-0.683,-0.8126>,<0,-1,0>,<-0.553,-0.6835,-0.8126>,USE THEO=YES
        HIT/BASIC,NORMAL,<0.0315,-0.683,-0.8128>,<0,-1,0>,<0.0315,-0.6837,-0.8128>,USE THEO=YES
        HIT/BASIC,NORMAL,<0.6048,-0.683,-0.813>,<0,-1,0>,<0.6048,-0.6837,-0.813>,USE THEO=YES
        HIT/BASIC,NORMAL,<1.1688,-0.683,-0.8132>,<0,-1,0>,<1.1688,-0.6843,-0.8132>,USE THEO=YES
        HIT/BASIC,NORMAL,<1.169,-0.683,-0.5246>,<0,-1,0>,<1.169,-0.684,-0.5246>,USE THEO=YES
        HIT/BASIC,NORMAL,<0.1022,-0.683,-0.5243>,<0,-1,0>,<0.1022,-0.6837,-0.5243>,USE THEO=YES
        HIT/BASIC,NORMAL,<-1.2736,-0.683,-0.5238>,<0,-1,0>,<-1.2736,-0.6835,-0.5238>,USE THEO=YES
        HIT/BASIC,NORMAL,<-1.2041,-0.683,-0.27>,<0,-1,0>,<-1.2041,-0.6831,-0.27>,USE THEO=YES
        HIT/BASIC,NORMAL,<-0.5116,-0.683,-0.2703>,<0,-1,0>,<-0.5116,-0.6831,-0.2703>,USE THEO=YES
        HIT/BASIC,NORMAL,<0.0786,-0.683,-0.2705>,<0,-1,0>,<0.0786,-0.6833,-0.2705>,USE THEO=YES
        HIT/BASIC,NORMAL,<0.6125,-0.683,-0.2706>,<0,-1,0>,<0.6125,-0.6835,-0.2706>,USE THEO=YES
        HIT/BASIC,NORMAL,<1.1602,-0.683,-0.2708>,<0,-1,0>,<1.1602,-0.6838,-0.2708>,USE THEO=YES
        ENDMEAS/
        DIM LOC13= LOCATION OF PLANE PLN4 UNITS=IN ,$
        GRAPH=OFF TEXT=OFF MULT=10.00 OUTPUT=BOTH HALF ANGLE=NO
        AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
        Y -0.6830 0.0005 0.0005 -0.6836 -0.0006 0.0001 <--------
        END OF DIMENSION LOC13

        See how I fixed your plane? do the same for your line, when you tell your CMM to take crappy hits. don't be surprised when it gives you crappy readings.
        (In Memory of my Loving wife, "Ronda" who I lost March 7, 2016. I love you baby.)
        They say "Nobody's Perfect." I must be Nobody.

        Comment


        • #5
          This is usually the result of an alignment which is not fully constrained, and has been discussed on the forum multiple times in the past -

          https://www.pcdmisforum.com/forum/pc...nals-in-report

          Comment


          • #6
            Maybe try to type in +0 after the nominal value.

            Comment


            • #7
              I don't use measured planes at all. Actually you could remove measured features from PCDMIS completely and I would be fine.

              In this case I would create auto points and then construct a plane. With auto points I have never seen the nominals update on their own.

              Comment


              • LaserJay
                LaserJay commented
                Editing a comment
                A-machine-insp

              • A-machine-insp
                A-machine-insp commented
                Editing a comment
                LaserJay I am much the same. Almost all of my programs are written the same way. In the extremely rare instance that I don't have CAD, I math it out and use auto features.

                I never have an issue @ing anyone. Possibly operator error on your end . The only one that goes funky for me is ogcharliebrown . His name never highlights for me but it still tags him.

              • LaserJay
                LaserJay commented
                Editing a comment
                A-machine-insp

                Probably operator error lol

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