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4 APPLICABLE FUNCTIONS
4.5 Machine diagnosis
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Threshold setting method
When the automatic threshold setting is used, [Pr. PF42 Friction failure prediction - Average characteristic] and [Pr. PF43
Friction failure prediction - Standard deviation] for determining the threshold value are automatically rewritten according to the
dynamic friction (at rated speed) estimated inside the servo amplifier. At this time, the threshold can be changed with [Pr.
PF40.0 Friction failure prediction - Threshold multiplication]. If [AL. 0F7.2 Friction failure prediction warning] is generated with
the value calculated by the automatic threshold setting, set [Pr. PF40.0 Friction failure prediction - Threshold multiplication] to
"6" or more. After the threshold is calculated in the servo amplifier, [Pr. PF34.0 Friction failure prediction warning selection]
changes to "2" (manual threshold setting).
For the manual threshold setting, the upper and lower limit thresholds can be calculated with the equations below. When [Pr.
PF40.0 Friction failure prediction - Threshold multiplication] is "0", the upper and lower limit thresholds are calculated as "5".
Upper limit threshold [0.1 %] = [Pr. PF42] + [Pr. PF43] × [Pr. PF40.0]
Lower limit threshold [0.1 %] = [Pr. PF42] - [Pr. PF43] × [Pr. PF40.0]
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Threshold reset method
To automatically reset thresholds after the upper and lower limit thresholds are set automatically, set [Pr. PF34.0 Friction
failure prediction warning selection] to "3" (threshold reset), then cycle the power. After cycling the power, the threshold value
is reset, and [Pr. PF34.0 Friction failure prediction warning selection] changes to "1" (threshold value automatic setting). If the
equipment parts are replaced after starting the friction failure prediction function, reset the friction thresholds and servo motor
total travel distance.