4 APPLICABLE FUNCTIONS
4.5 Machine diagnosis
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4
For the vibration failure prediction function, the threshold that triggers [AL. 0F7.1 Friction failure prediction warning] can be set
using the following two methods.
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Automatic threshold setting
From the vibration level estimated by the vibration estimation function, a threshold that triggers [AL. 0F7.1 Vibration failure
prediction warning] is automatically calculated in the servo amplifier. With this setting, the vibration failure prediction function
can be used without setting a threshold. However, after the vibration failure prediction function operates, the equipment must
be operated for about 90 hours before vibration failure prediction is actually performed. [AL. 0F7.1] does not occur until the
calculation of the threshold value in the servo amplifier is complete.
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Manual threshold setting
This is a method of setting a threshold that triggers [AL. 0F7.1 Vibration failure prediction warning] with [Pr. PF40.1 Vibration
failure prediction - Threshold multiplication], [Pr. PF45 Vibration failure prediction - Average characteristics], or [Pr. PF46
Vibration failure prediction - Standard deviation]. For the manual threshold setting, vibration failure prediction will start
immediately after the vibration failure prediction function begins operation. Thus, if the vibration amplitude threshold is known,
or the equipment to be used is configured the same as another piece of equipment that had been used for calculating the
threshold with the automatic threshold setting, an initial failure and other types of failures can also be detected by the manual
threshold setting.
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Vibration failure prediction warning setting
Set [Pr. PF34.1 Vibration failure prediction warning selection] to "1" (automatic threshold setting) or "2" (manual threshold
setting) to enable vibration failure prediction warning.
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Threshold setting method
When the automatic threshold setting is used, [Pr. PF45 Vibration failure prediction - Average characteristic] and [Pr. PF46
Vibration failure prediction - Standard deviation] for determining a threshold are automatically rewritten according to the
vibration level estimated in the servo amplifier. At this time, the threshold can be changed with [Pr. PF40.1 Vibration failure
prediction - Threshold multiplication]. If [AL. 0F7.1 Vibration failure prediction warning] is generated with the value calculated
by the automatic threshold setting, set [Pr. PF40.1 Vibration failure prediction - Threshold multiplication] to "6" or more. Once
the calculation of the threshold inside the servo amplifier completes, [Pr. PF34.1 Vibration failure prediction warning selection]
will change 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.
PF40.1 Vibration failure prediction - Threshold multiplication] is "0", the threshold is calculated as "5".
Threshold [0.1 %] = [Pr. PF45 Vibration failure prediction - Average characteristic] + [Pr. PF46 Vibration failure prediction -
Standard deviation] × [Pr. PF40.1 Vibration failure prediction - Threshold multiplication]
The values of [Pr. PF45 Vibration failure prediction - Average characteristic] and [Pr. PF46 Vibration failure prediction -
Standard deviation] can also be determined by measuring the torque ripple with the graph function of MR Configurator2. The
threshold for the vibration failure prediction can also be set by setting the measurement values for the average and the
standard deviation of the torque ripple from the graph function in [Pr. PF45 Vibration failure prediction - Average
characteristics] and [Pr. PF46 Vibration failure prediction - Standard deviation].
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Threshold reset method
To automatically reset a threshold after the threshold is set automatically, set [Pr. PF34.1 Vibration failure prediction warning
selection] to "3" (threshold reset), then cycle the power. After the power is cycled, the threshold is reset and [Pr. PF34.1
Vibration failure prediction warning selection] changes to "1" (automatic threshold setting). If servo parameters such as gains
and machine resonance suppression filters are changed, or any part of the equipment is replaced after the vibration failure
prediction function is started, reset the threshold.
Servo
parameter
Symbol
Name
Outline
PF34.1
*MFP
Vibration failure prediction
warning selection
Set when the vibration failure prediction warning is enabled.
0: Disabled (initial value)
1: Enabled (automatic threshold setting)
2: Enabled (manual threshold setting)
3: Threshold reset
