Polytec PSV 300, Руководство по оборудованию

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To set the tracking filter, the diagram in To set the tracking filter, the diagram in fi fi gu gu re re 4. 4. 7 7 can be summarized in the can be summarized in the
following general rules: following general rules:
 
For frequencies above 100 For frequencies above 100kHz as a general rule the tracking filter should kHz as a general rule the tracking filter should
be switched off. In principle it be switched off. In principle it can follow higher frequencies but in can follow higher frequencies but in this this
range amplitude errors of up to approximately 10% can occur due to range amplitude errors of up to approximately 10% can occur due to
dynamic errors.
dynamic errors.
 
For medium velocities and frequencies, the acceleration limits of the For medium velocities and frequencies, the acceleration limits of the
tracking filter have to be
tracking filter have to be taken into consideration. The optimal setting taken into consideration. The optimal setting
must be found with the must be found with the diagram. If the velocity or acceleration limits are diagram. If the velocity or acceleration limits are
exceeded, the tracking filter loses lock (refer to exceeded, the tracking filter loses lock (refer to se se ct ct ion ion C.2 C.2 ). This will ). This will
cause serious signal distortions, an example of which can be seen in cause serious signal distortions, an example of which can be seen in
fi
fi gu gu re re 4. 4. 8 8 ..
The upper trace in The upper trace in fi fi gu gu re re 4. 4. 8 8 shows the sinusoidal velocity signal with the shows the sinusoidal velocity signal with the
tracking filter in position OFF. The lower trace shows the velocity signal tracking filter in position OFF. The lower trace shows the velocity signal
with the tracking fil
with the tracking filter in position SLOW. The tracking filter is on the limit of ter in position SLOW. The tracking filter is on the limit of
the range where it the range where it loses lock, the signal is partly distorted. loses lock, the signal is partly distorted.
 
IIn n tth he e m me ea as su urre em me en nt t rra an ng ge es s 1 1 , , 5 5 a an nd d 1 10 0 , , tth he e ttrra ac ck kiin ng g ffiilltte err
should be set to SLOW as a general rule. should be set to SLOW as a general rule.
 
Using the velocity decoder PLL-DC the tracking filter is particularly Using the velocity decoder PLL-DC the tracking filter is particularly
important. For technical reasons the PLL-DC is more
important. For technical reasons the PLL-DC is more sensitive to dropouts sensitive to dropouts
than the decoder OVD-04. Thus the tracking filter should be set than the decoder OVD-04. Thus the tracking filter should be set to SLOW to SLOW
as long as the acceleration limit is not exceeded (refer to as long as the acceleration limit is not exceeded (refer to fi fi gu gu re re 4. 4. 7 7 ). ).
Figure 4.8: True velocity signal (top) and signal when the tracking filter loses lock (bottom) Figure 4.8: True velocity signal (top) and signal when the tracking filter loses lock (bottom)
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s s
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s s
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s s
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