Mitsubishi Electric MELSERVO-J5 User Manual page 294

■Threshold setting method
When [Pr. PF51.5 Static friction failure prediction warning selection] is set to "1" (automatic threshold setting), [Pr. PF69 Static
friction failure prediction - Average characteristics] and [Pr. PF70 Static friction failure prediction - Standard deviation] for
determining a threshold are automatically rewritten according to the static friction estimated in the servo amplifier.
The threshold can be changed with [Pr. PF52.4 Static friction failure prediction - Threshold multiplication]. If [AL. 0F7 Machine
diagnosis warning] is incorrectly detected with the value calculated by the automatic threshold setting, increase the value of
[Pr. PF52.4 Static friction failure prediction - Threshold multiplication].
After the threshold is calculated in the servo amplifier, [Pr. PF51.5 Static friction failure prediction warning selection] changes
to "2" (manual threshold setting).
Set [Pr. PF51.5 Static friction failure prediction warning selection] to "2" (manual threshold setting) to set the threshold
manually. The upper and lower thresholds can be set by [Pr. PF52.4 Static friction failure prediction - Threshold multiplication],
[Pr. PF69 Static friction failure prediction - Average characteristic], and [Pr. PF70 Static friction failure prediction - Standard
deviation], and are calculated with the following formula. When [Pr. PF52.4 Static friction failure prediction - Threshold
multiplication] is "0" in the following formula, calculate the upper and lower thresholds with the static friction failure prediction
threshold multiplication as 5.
Upper limit threshold [0.1 %] = [Pr. PF69] + [Pr. PF70] × [Pr. PF52.4]
Lower limit threshold [0.1 %] = [Pr. PF69] - [Pr. PF70] × [Pr. PF52.4]
Servo Symbol
parameter
PF52.4 MFPP
PF69 SPAV
PF70 SPSD
*1 When "0" is set, the threshold is 5 times.
*2 Enabled when [Pr. PF51.5 Static friction failure prediction warning selection] is set to "2" (manual threshold setting).
When [Pr. PF51.5 Static friction failure prediction warning selection] is set to "1" (automatic threshold setting), the value will be
calculated automatically from the estimated static friction torque.
4 APPLICABLE FUNCTIONS
292
4.5 Machine diagnosis
Name Description
Static friction failure Set a multiplying factor for calculating the threshold used in the static friction failure
prediction - Threshold prediction function.
multiplication Setting a small threshold multiplication for static friction failure prediction will decrease the
threshold used for static friction failure prediction. Thus, this will enable the prediction of a
failure at an early stage, but will increase the possibility of erroneously detecting a failure.
*1
Initial value: 0h
Static friction failure Set a static friction torque average.
prediction - Average Initial value: 0 [0.1 %]
characteristics
Static friction failure Set a standard deviation of static friction torque.
prediction - Standard Initial value: 0 [0.1 %]
deviation
*2
*2