Mitsubishi Electric MR-J5 Series User Manual page 143

■Setting of Failure prediction - Servo motor total travel distance
For the automatic threshold setting, set the Failure prediction - Servo motor total travel distance. It is recommended that the
servo motor total travel distance for the failure prediction be set to about the same as the rated life presented by each guide
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manufacturer and ball screw manufacturer. For example, for a rated life of 8 × 10 rev, set [Pr. PF53 Failure prediction - Servo
motor total travel distance] to "80000" [10 rev].
■Threshold setting method
When automatic threshold setting is used, the servo parameter that determines the threshold value, being [Pr. PF54 Friction
failure prediction - Average characteristic] and [Pr. PF55 Friction failure prediction - Standard deviation], 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. PF52.0 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. PF52.0 Friction failure prediction -
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Threshold multiplication] to "6" or more. After the threshold is calculated in the servo amplifier, [Pr. PF51.0 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.
PF52.0 Friction failure prediction - Threshold multiplication] is "0", the upper and lower limit thresholds are calculated as "5".
Upper limit threshold [0.1 %] = [Pr. PF54] + [Pr. PF55] × [Pr. PF52.0]
Lower limit threshold [0.1 %] = [Pr. PF54] - [Pr. PF55] × [Pr. PF52.0]
■Threshold reset method
To automatically reset thresholds after the upper and lower limit thresholds are set automatically, set [Pr. PF51.0 Friction
failure prediction warning selection] to "3" (threshold reset), then cycle the power. After cycling the power, the threshold value
is reset, and [Pr. PF51.0 Friction failure prediction warning selection] changes to "1" (threshold value automatic setting). If the
equipment parts are replaced after the friction failure prediction function operates, reset the friction thresholds and servo
motor total travel distance.
4 APPLICABLE FUNCTION
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4.3 Machine diagnosis