Have you ever run into the situation when you need to measure a single feature (i.e. circle) with a star probe that has tips with different size, and wonder whether the probe compensation is done correctly or not? I did this test in PC-Dmis:

1, My star probe configured as (following the order of connection # in pc-dmis): 
===== TIP 1 (3X15 MM), TIP 2 (6X10 MM), TIP 3 (2X20 MM), TIP 4 (4X10 MM)
2, Use TIP 1 to set center of cal. sphere (19.05mm) as origin, then measure the equator as a CIR1 with TIP 1, and with all tips (CIR2)
3, Output CIR1 and each hit;
4, Output CIR2 and each hit;
5, Measure each hit as vector point with the corresponding tip;
6, Output each vector hit;
7, Output a constructed circle (BF) with all 4 vector hits;
8, Output a constructed circle (BFRECOMP) with all 4 vector hits;

My 4 hits are: +X, +Y, -X, -Y, and below is the results:
-------------------------------------------------------------------
PART NAME : Test_StarPrb
REV NUMBER : 
SER NUMBER : 
STATS COUNT : 1

===== TIP 1 (3X15 MM)

DIM LOC1= LOCATION OF CIRCLE CIR1 UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 0.000 0.000 0.000 ----#----
Y 0.000 0.100 0.100 -0.002 -0.002 0.000 ----#----
Z 0.000 0.100 0.100 0.000 0.000 0.000 ----#----
D 19.050 0.100 0.100 19.047 -0.003 0.000 ----#----

DIM LOC2= LOCATION OF POINT CIR1.HIT[1] UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 9.525 0.100 0.100 9.524 -0.001 0.000 ----#----
Y 0.000 0.100 0.100 0.000 0.000 0.000 ----#----
Z 0.000 0.100 0.100 0.000 0.000 0.000 ----#----

DIM LOC3= LOCATION OF POINT CIR1.HIT[2] UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 -0.002 -0.002 0.000 ----#----
Y 9.525 0.100 0.100 9.521 -0.004 0.000 ----#----
Z 0.000 0.100 0.100 0.000 0.000 0.000 ----#----

DIM LOC4= LOCATION OF POINT CIR1.HIT[3] UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X -9.525 0.100 0.100 -9.524 0.001 0.000 ----#----
Y 0.000 0.100 0.100 -0.001 -0.001 0.000 ----#----
Z 0.000 0.100 0.100 0.001 0.001 0.000 ----#----

DIM LOC5= LOCATION OF POINT CIR1.HIT[4] UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 0.001 0.001 0.000 ----#----
Y -9.525 0.100 0.100 -9.525 0.000 0.000 ----#----
Z 0.000 0.100 0.100 0.001 0.001 0.000 ----#----

===== TIP 1 (3X15 MM), TIP 2 (6X10 MM)
===== TIP 3 (2X20 MM), TIP 4 (4X10 MM) 

DIM LOC6= LOCATION OF CIRCLE CIR2 UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 0.001 0.001 0.000 ----#----
Y 0.000 0.100 0.100 0.001 0.001 0.000 ----#----
Z 0.000 0.100 0.100 0.001 0.001 0.000 ----#----
D 19.050 0.100 0.100 19.043 -0.007 0.000 ----#----

===== TIP 4 (4X10 MM) 

DIM LOC7= LOCATION OF POINT CIR2.HIT[1] UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 9.525 0.100 0.100 9.522 -0.003 0.000 ----#----
Y 0.000 0.100 0.100 -0.002 -0.002 0.000 ----#----
Z 0.000 0.100 0.100 0.000 0.000 0.000 ----#----

===== TIP 1 (3X15 MM)

DIM LOC8= LOCATION OF POINT CIR2.HIT[2] UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 -0.001 -0.001 0.000 ----#----
Y 9.525 0.100 0.100 9.523 -0.002 0.000 ----#----
Z 0.000 0.100 0.100 0.001 0.001 0.000 ----#----

===== TIP 2 (6X10 MM)

DIM LOC9= LOCATION OF POINT CIR2.HIT[3] UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X -9.525 0.100 0.100 -9.519 0.006 0.000 ----#----
Y 0.000 0.100 0.100 -0.001 -0.001 0.000 ----#----
Z 0.000 0.100 0.100 0.002 0.002 0.000 ----#----

===== TIP 3 (2X20 MM)

DIM LOC10= LOCATION OF POINT CIR2.HIT[4] UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 0.000 0.000 0.000 ----#----
Y -9.525 0.100 0.100 -9.521 0.004 0.000 ----#----
Z 0.000 0.100 0.100 0.000 0.000 0.000 ----#----

===== TIP 4 (4X10 MM) 

PART NUMBER=Test_StarPrb DATE=13/06/2013 TIME=11:37:07 AM PAGE#=2
DIM LOC11= LOCATION OF POINT PNT1 UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 9.525 0.100 0.100 9.523 -0.002 0.000 ----#----
Y 0.000 0.100 0.100 0.001 0.001 0.000 ----#----
Z 0.000 0.100 0.100 -0.001 -0.001 0.000 ----#----

===== TIP 1 (3X15 MM)

DIM LOC12= LOCATION OF POINT PNT2 UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 0.000 0.000 0.000 ----#----
Y 9.525 0.100 0.100 9.523 -0.002 0.000 ----#----
Z 0.000 0.100 0.100 0.000 0.000 0.000 ----#----

===== TIP 2 (6X10 MM)

DIM LOC13= LOCATION OF POINT PNT3 UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X -9.525 0.100 0.100 -9.520 0.005 0.000 ----#----
Y 0.000 0.100 0.100 0.003 0.003 0.000 ----#----
Z 0.000 0.100 0.100 0.002 0.002 0.000 ----#----

===== TIP 3 (2X20 MM)

DIM LOC14= LOCATION OF POINT PNT4 UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 0.001 0.001 0.000 ----#----
Y -9.525 0.100 0.100 -9.522 0.003 0.000 ----#----
Z 0.000 0.100 0.100 0.000 0.000 0.000 ----#----

 

===== CONSTRUCTED (AUTO/BF)

DIM LOC15= LOCATION OF CIRCLE CC2_AUTO UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 0.001 0.001 0.000 ----#----
Y 0.000 0.100 0.100 0.000 0.000 0.000 ----#----
Z 0.000 0.100 0.100 0.000 0.000 0.000 ----#----
D 19.050 0.100 0.100 19.044 -0.006 0.000 ----#----

===== CONSTRUCTED (BFRECOMP)

DIM LOC16= LOCATION OF CIRCLE CC2_RECOMP UNITS=MM
AX NOMINAL +TOL -TOL MEAS DEV OUTTOL 
X 0.000 0.100 0.100 0.001 0.001 0.000 ----#----
Y 0.000 0.100 0.100 0.000 0.000 0.000 ----#----
Z 0.000 0.100 0.100 0.000 0.000 0.000 ----#----
D 19.050 0.100 0.100 19.044 -0.006 0.000 ----#----
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The good thing is they'are all within microns, which means even when the circle is measured with different size tips, probe compensation is done correctly.