Okuma Renishaw Calibration Variables

With VS Usage of Variables

Variable	Purpose
VSTOD[21]	X-axis stylus ball radius (XRAD)
VSTOD[22]	Y-axis stylus ball radius (YRAD)
VSTOD[23]	X-axis stylus offset (XOFF)
VSTOD[25]	Y-axis stylus offset (YOFF)
VSTOD[26]	Software Signature
VSTOD[27]	Probe delay
VSTOD[28]	Machine stopping distance
VSTOD[29]	Measuring feedrate
VSTOD[30]	Fast positioning feedrate
VSTOD[31]	30° stylus ball radius
VSTOD[32]	60° stylus ball radius
VSTOD[33]	120° stylus ball radius
VSTOD[34]	150° stylus ball radius
VSTOD[35]	210° stylus ball radius
VSTOD[36]	240° stylus ball radius
VSTOD[37]	300° stylus ball radius
VSTOD[38]	330° stylus ball radius
VSTOD[39]	Z calibration ball radius

With VC Variable Usage (Base Number of 21)

Variable	Purpose
VC21	X-axis stylus ball radius (XRAD)
VC22	Y-axis stylus ball radius (YRAD)
VC23	X-axis stylus offset (XOFF)
VC24	Y-axis stylus offset (YOFF)
VC25	Software Signature
VC26	Probe delay
VC27	Machine stopping distance
VC28	Measuring feedrate
VC29	Fast positioning feedrate
VC31	30° stylus ball radius
VC32	60° stylus ball radius
VC33	120° stylus ball radius
VC34	150° stylus ball radius
VC35	210° stylus ball radius
VC36	240° stylus ball radius
VC37	300° stylus ball radius
VC38	330° stylus ball radius

Worked Example: A Calibration Run End to End

Here is the sequence an operator actually runs to fill the calibration variables in the tables above. Setup: a certified ring gauge is clamped to the table, its bore diameter is known from the cert, and the probe is in the spindle with the stylus ball roughly centered over the ring by eye. Calibration macros ship alongside the O98xx Inspection Plus measuring macros — verify the exact macro numbers against the package installed on your machine before running this.

( ===== STYLUS CALIBRATION IN A RING GAUGE ===== )
( SETUP: 50.0005 MM CERTIFIED RING GAUGE BOLTED TO THE TABLE )
( PROBE IN SPINDLE, BALL CENTERED OVER THE BORE BY EYE )
G00 X0 Y0                    ( POSITION OVER THE RING GAUGE CENTER )
G00 Z-5.0                    ( DROP THE STYLUS BALL BELOW THE GAUGE TOP FACE )
CALL O9802 D=50.0005         ( RADIUS CALIBRATION - D IS THE CERTIFIED BORE DIAMETER )
CALL O9803 D=50.0005         ( OFFSET CALIBRATION - FINDS STYLUS RUNOUT VS SPINDLE CL )
G00 Z100.0                   ( RETRACT CLEAR OF THE GAUGE )
M02

When the run completes, the radius calibration has written the X and Y stylus ball radii — VSTOD[21]/VSTOD[22] (XRAD/YRAD), or VC21/VC22 on a VC-configured installation — and the offset calibration has written the stylus offsets: VSTOD[23] (XOFF) and VSTOD[25] (YOFF), which land in VC23 and VC24 under the VC scheme (note the VS and VC numbering diverge for YOFF, per the tables above). If your package runs the vectored calibration, the angled ball radii VSTOD[31]–VSTOD[38] (VC31–VC38) are filled as well.

Verifying the result: page to the variable display and sanity-check the values before trusting a single measurement. XRAD/YRAD should read slightly smaller than the stylus ball's nominal radius (trigger-force lobing eats a few microns — a 6 mm ball calibrating near 2.95 mm rather than 3.000 is normal), and X and Y should agree closely with each other. XOFF/YOFF should be small — typically well under 0.1 mm — and repeatable run to run. A radius wildly off nominal or an offset in the tenths of a millimeter usually means the gauge diameter was keyed in wrong or the ring moved.

References

• Renishaw, Inspection Plus Programming Manual, Renishaw plc.
• Okuma, OSP Programming Manual, Okuma Corporation.