HEIDENHAIN iTNC 530 Service Manual page 71

With indirect position measurement, couplings and transmission systems (belts, gears, etc.),
Indirect position
ball screw with recirculating ball nut, guideways are outside the control loop.
measurement
See "Position Measurement via Motor Encoder (Indirect Position Measurement)" on page 18 –
Flowchart
311.
If with indirect measurement, e.g., the unusual traversing noise is fainter or if there is no noise
Conclusion
at all, the error cause may be due to the mechanics of the machine (e.g., reversal error, worn
guideways).
For indirect path measurement the direct encoder (scale, scale tape) is not required.
Consequently, the direct encoder may be the error cause.
Observe the quality of the encoder signals (e.g. with a PWT 18 (for 1Vpp) or with PWM 9)
while moving the table with indirect path measurement.
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