Mitsubishi Electric MELSERVO-J5 MR-J5 Series User Manual page 222

■Threshold setting method
When [Pr. PF34.5 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 dynamic friction (at rated speed) estimated in the servo
amplifier.
The threshold can be changed with [Pr. PF40.4 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. PF40.4 Static friction failure prediction - Threshold multiplication].
After the threshold is calculated in the servo amplifier, [Pr. PF34.5 Static friction failure prediction warning selection] changes
to "2" (manual threshold setting).
Set [Pr. PF34.5 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. PF40.4 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. Moreover, in the following formula, when [Pr. PF40.4 Static friction
failure prediction - Threshold multiplication] is 0, calculate the upper and lower threshold with the static friction failure
prediction threshold multiplication as 5.
Upper limit threshold [0.1 %] = [Pr. PF69] + [Pr. PF70] × [Pr. PF40.4]
Lower limit threshold [0.1 %] = [Pr. PF69] - [Pr. PF70] × [Pr. PF40.4]
Servo Symbol
parameter
PF40.4 MFPP
PF69 SPAV
PF70 SPSD
*1 When "0" is set, the threshold is 5 times.
*2 Enabled when [Pr. PF34.5 Static friction failure prediction warning selection] is set to "2" (manual threshold setting).
When [Pr. PF34.5 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.
*3 Enabled when [Pr. PF34.5 Static friction failure prediction warning selection] is set to "2" (manual threshold setting).
When [Pr. PF34.5 Static friction failure prediction warning selection] is set to "1" (automatic threshold setting), the value will be
calculated automatically from the estimated friction torque at rated speed.
■Threshold reset method
When the automatic threshold setting is performed again after being used to set the upper and lower threshold, set [Pr.
PF34.5 Static friction failure prediction warning selection] to "3" (threshold reset), then cycle the power or perform the software
reset. After cycling the power or resetting the software, the threshold is reset and [Pr. PF34.5 Static friction failure prediction
warning selection] changes to "1" (automatic threshold setting).
If a part on the equipment is replaced after the static friction failure prediction function has started, reset the static friction
threshold and machine total travel distance.
4 APPLICABLE FUNCTIONS
220
4.5 Machine diagnosis
Name
Static friction failure prediction -
Threshold multiplication
Static friction failure prediction -
Average characteristics
Static friction failure prediction -
Standard deviation
Description
Set a multiplication for calculating the threshold used in the static friction failure
prediction function.
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
*1
erroneously detecting a failure.
Initial value: 0h
Set a static friction torque average.
Initial value: 0.0 [%]
Set a standard deviation of static friction torque.
Initial value: 0.0 [%]
*2
*3