4 APPLICABLE FUNCTIONS
4.5 Machine diagnosis
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4
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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. PF52.1 Vibration
failure prediction - Threshold multiplication], [Pr. PF56 Vibration failure prediction - Average characteristics], or [Pr. PF57
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. PF51.1 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. PF56 Vibration failure prediction - Average characteristic] and [Pr. PF57
Vibration failure prediction - Standard deviation] for determining the threshold value are automatically rewritten according to
the dynamic friction (at rated speed) estimated inside the servo amplifier. At this time, the threshold can be changed with [Pr.
PF52.1 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. PF52.1 Vibration failure prediction - Threshold
multiplication] to "6" or more. Once the calculation of the threshold inside the servo amplifier completes, [Pr. PF51.1 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.
PF52.1 Vibration failure prediction - Threshold multiplication] is "0", the threshold is calculated as "5".
Threshold [0.1 %] = [Pr. PF56 Vibration failure prediction - Average characteristic] + [Pr. PF57 Vibration failure prediction -
Standard deviation] × [Pr. PF52.1 Vibration failure prediction - Threshold multiplication]
The values of [Pr. PF56 Vibration failure prediction - Average characteristic] and [Pr. PF57 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. PF56 Vibration failure prediction - Average
characteristics] and [Pr. PF57 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. PF51.1 Vibration failure prediction warning
selection] to "3" (threshold reset), then cycle the power. After the power is cycled, the threshold is reset and [Pr. PF51.1
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
PF51.1
*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
