Balluff BML-S1G0 Serie Notice D'utilisation D'origine page 55

BML-S1G0-_7_ _-M5E_-_0-_ _
Absolute Magnetically Coded Position Measuring System
7
Diagnosis
7.1 BEF diagnosis data
The position data is compiled from a total of 30 magnetic
field sensors. Different parameters such as distance, side
offset, ambient temperature, angle to the magnetic tape,
and external magnetic fields have a direct effect on the
measuring accuracy. The measuring accuracy is specified
in BEF (Balluff Exactness Factor) using a plausibility check.
To perform the plausibility check, the sensor head must be
moved over the tape with a speed of <1 m/s. If no value
can be determined (speed > 1 m/s or direction of
movement reversed), the BEF value = 15. If the
measurement is successful, the BEF has a value between
0 and 14.
Fig. 7-1: Position over time
Fig. 7-3: Position over time for a simulated magnetic tape problem
In Fig. 7-1 and Fig. 7-2 the sensor head is located within
the working range. In Fig. 7-3 and Fig. 7-4 the magnetic
tape is sometimes covered by a magnetizable material
between positions 50.000 and 70.000. There, the BEF
value is reduced compared to the intact magnetic tape,
even though the position can still be detected reliably.
The higher the BEF number, the better the quality of the
internal signals. Values down to 1 are sufficient.
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Fig. 7-2: BEF number over the path
Fig. 7-4: BEF number over the path for a simulated
magnetic tape problem
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