L974 2-Point Measurement On Diameter - Siemens SINUMERIK 840 User Manual

4 Measuring Cycles for Turning Machines

4.3.4 L974 2-point measurement on diameter

4.3.4 L974 2-point measurement on diameter
The measuring cycle ascertains the actual value of the workpiece in relation to the workpiece
zero point and the set/actual difference.
The cycle measures the diameter by measuring the upper (1st measurement) and the lower
(2nd measurement) point without turning the part. In this case, the probe need not be cali-
brated anymore. Measuring must not be carried out in any other order as otherwise the
protection zone will not have any effect!
A protection zone must be specified with R18 and R19 because the cycle positions automati-
cally with G00 from the 1st to the 2nd measuring point. A negative setpoint is not possible.
If double sensors are used with 2D numbers, the protection zone always refers to the active D
number. Therefore the protection zone dimensions required in the construction along the
measuring axis must be increased by the amount 2r (outside distance between the 2 probe
balls).
The maximum diameter that can be measured depends on the traversing range of the turret
slide in negative direction and on the geometry dimension of the probe in X.
The actual value and the set/actual difference are determined on the basis of the two
measurements.
An empirical value stored in SDC is subsequently allowed for with the correct sign.
In addition, averaging is performed over several parts and the tolerance bands are checked
(Section 1.7.1).
The probe is located outside the protection zone "X" and "Z" on completion of measurement.
No automatic compensation or a length compensation is carried out, depending on the
definition of R10.
Preconditions:
• The workpiece must be positioned with M19 prior to cycle call when necessary.
• The probe must be positioned with tool offset and G53 to face the surface to be
measured (Fig. 4.9).
If double sensors are used with 2D numbers, the protection zone always refers to the active D
number. Therefore the protection zone dimensions required in the construction along the
measuring axis must be increased by the amount 2r (outside distance between the 2 probe
balls).
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SINUMERIK 840/850/880 (BN)
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