Mitsubishi Electric MR-J5 Series User Manual page 167

■Friction failure prediction function
The friction failure prediction function predicts a failure of the equipment from the increase/decrease in the static friction
estimated by the friction estimation function. If a failure of the equipment is predicted, [AL. 0F7 Machine diagnosis warning]
occurs. The threshold of [AL. 0F7 Machine diagnosis warning] can be set automatically, and therefore this function is easier to
use than the belt tension deterioration prediction function. In order for the static friction failure prediction function to detect the
increase/decrease of the static friction, the accuracy of belt tension deterioration is low, and the initial stretch of the belt may
trigger [AL. 0F7 Machine diagnosis warning].
■Belt tension deterioration prediction function
For the belt tension deterioration prediction function, [AL. 0F7 Machine diagnostic warning] occurs when the belt tension that
is estimated from the servo amplifier internal data is equal to or lower than the inputted threshold of the belt tension servo
parameter. Although the relationship between the belt tension and the static friction needs to be inputted with servo
parameters, this function can improve the accuracy in detection of the belt tension deterioration by estimating the belt tension
and outputting [AL. 0F7 Machine diagnosis warning].
Differences between the static friction failure prediction function and the belt tension deterioration function are shown on the
following table.
Item Friction failure prediction function
Determination criteria Static friction
Threshold setting Automatic setting possible
Input required servo [Pr. PF34.5 Static friction failure prediction - Warning selection]
parameter [Pr. PF41 Failure prediction - Servo motor total travel distance]
Belt tension deterioration Low
detection accuracy
Belt tension deterioration prediction function
Belt tension
Manual setting
[Pr. PF71.0 Belt tension deterioration prediction function
selection]
[Pr. PF72 Belt tension on installation]
[Pr. PF73 Belt tension when extended]
[Pr. PF74 Static friction during installation]
[Pr. PF75 Static friction when extended]
[Pr. PF76 Belt tension irregular threshold]
High
4 APPLICABLE FUNCTION
4.3 Machine diagnosis
4
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