4 APPLICABLE FUNCTIONS
4.5 Machine diagnosis
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*1 The data of the estimated static friction and dynamic friction can be saved on the machine diagnosis screen of MR Configurator2.
*2 Setting the value estimated by the automatic threshold setting in [Pr. PF19] and [Pr. PF20] reduces the possibility of an erroneous
detection for failure prediction although the function operates properly with the initial value of [Pr. PF19] and [Pr. PF20].
*3 If the equipment has been operated for less than continuous three hours, or the friction estimation has not finished for the travel direction
set in [Pr. PF40], the threshold is not calculated automatically.
For the friction failure prediction function, the threshold that triggers [AL. 0F7.2 Friction failure prediction warning] can be set
using the following two methods.
■
Automatic threshold setting
This is a method to automatically calculate the threshold for triggering [AL. 0F7.2 Friction failure prediction warning] using the
dynamic friction (at rated speed) estimated by the friction estimation function. With this setting, the friction failure prediction
function can be used without setting a threshold. However, after the machine total travel distance exceeds 1/2 of [Pr. PF41
Failure prediction - Servo motor total travel distance], a threshold is not automatically set until the equipment is operated
continuously for 3 hours or more, and operated in the position mode or velocity mode for a cumulative time of 90 hours or
more. [AL. 0F7.2 Friction failure prediction warning] does not occur until the calculation of the threshold value in the servo
amplifier is complete.
■
Manual threshold setting
This is a method of setting a threshold that triggers [AL. 0F7.2 Friction failure prediction warning] with [Pr. PF40.0 Friction
failure prediction - Threshold multiplication], [Pr. PF42 Friction failure prediction - Average characteristics], or [Pr. PF43
Friction failure prediction - Standard deviation]. For the manual threshold setting, friction failure prediction starts when the
machine total travel distance exceeds 1/2 of [Pr. PF41 Failure prediction - Servo motor total travel distance]. Thus, if the
dynamic friction threshold is known, or the equipment is configured the same as another piece of equipment used for
calculating the threshold with the automatic threshold setting, an initial failure and other types of failures can also be detected
with the manual threshold setting.
When performing manual threshold setting on the equipment for which automatic threshold setting has been made once, set
the value, which is obtained by the automatic threshold setting, in [Pr. PF19 Friction failure prediction - Compensation
coefficient 1] and [Pr. PF20 Friction failure prediction - Compensation coefficient 2]. Setting [Pr. PF19 Friction failure prediction
- Compensation coefficient 1] and [Pr. PF20 Friction failure prediction - Compensation coefficient 2] reduces the possibility of
erroneous detection of failure prediction.
■
Setting "Friction failure prediction warning"
Set [Pr. PF34.0 Friction failure prediction warning selection] to "1" (automatic threshold setting) or "2" (manual threshold
setting) to enable the friction failure prediction warning.
■
Setting "Failure prediction - Servo motor total travel distance"
Set the "Failure prediction - Servo motor total travel distance" when using the automatic threshold setting. It is recommended
that the servo motor total travel distance for failure prediction be set to about the same as the rated life suggested by the
manufacturers of the guides and ball screws being used. For example, for a rated life of 8 × 10
5
rev, set [Pr. PF41 Failure
prediction - Servo motor total travel distance] to "80000" [10 rev].
Servo
parameter
Symbol
Name
Outline
PF34.0
*MFP
Friction failure prediction warning
selection
Use this servo parameter to enable the friction failure prediction warning.
0: Disabled (initial value)
1: Enabled (automatic threshold setting)
2: Enabled (manual threshold setting)
3: Threshold reset
