4 APPLICABLE FUNCTIONS
4.5 Machine diagnosis
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4
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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]
*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.
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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.
Servo
parameter
Symbol
Name
Description
PF40.4
MFPP
Static friction failure prediction -
Threshold multiplication
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
erroneously detecting a failure.
Initial value: 0h
PF69
SPAV
Static friction failure prediction -
Average characteristics
Set a static friction torque average.
Initial value: 0.0 [%]
PF70
SPSD
Static friction failure prediction -
Standard deviation
Set a standard deviation of static friction torque.
Initial value: 0.0 [%]