Maintenance
Machine diagnosis function
- J4 Only
- Sample screen
- End user
- Predictive maintenance
- Maintenance
- GT27
- GT25
- GT23
- GT21
- GS21
- GT SoftGOT2000*
- * GT SoftGOT2000 supports MR-J4-B(-RJ), MR-J4W2-B,
MR-J4W3-B, and MR-JE-B only.
Predict machine deterioration and improve system preventive
maintenance without a need for personal computer
- B
- B-RJ
- WB
- A
- A-RJ
- GF
- GF-RJ
- JE-B
- JE-A
- JE-C
Challenges
How can I predict deterioration of a
machine if it has excessive load and is
frequently accelerated?
Solutions
GOT can display estimated values (machine friction, torque vibration, etc.) that are collected by the
machine diagnosis function of the servo amplifier. The difference between the initial value (at the
startup) and the current value can be used to predict deterioration of the machine. Using this
function with the GOT's alarm function will help you perform timely maintenance of machine parts.
Vibration increased
after starting operation
Descriptions of items on the machine diagnosis screen
| Item |
Description |
| Estimated friction value |
Detect the estimated static friction (coulomb friction) (including
gravity and etc.) and dynamic friction (viscous friction) coefficient
of guides or ball screws according to the operation patterns. |
| |
Friction torque
at rated speed (%) |
Friction in operation at the rated speed.
The value indicates the ratio (%) against the rated torque.
The value increases as the machine deteriorates. |
| |
Static friction
(coulomb friction) (%) |
Regardless of the motor speed, a constant value is applied to friction.
When an object begins to move, the torque must be greater than or equal to the static friction (coulomb friction) torque.
The value indicates the ratio (%) against the rated torque.
The value increases as the machine deteriorates. |
| Vibration estimation |
The vibration estimation function observes the torque vibration and estimates the vibration level and the vibration frequency of high-frequency micro vibrations.
This function allows checking of the increase of vibration level and the change in the vibration frequency that are caused by deterioration of a guide, a ball screw, a belt, etc. due to age. |
| |
Oscillation frequency (Hz) |
Frequency of torque vibration when a machine vibrates during operation or it is not operating.
The value indicates the frequency when the machine oscillates due to a cause such as deterioration of the machine due to age. |
| |
Vibration level (%) |
Torque amplitude when a machine vibrates during operation or it is not operating.
The value indicates the ratio (%) against therated torque.
The value increases as the machine oscillation increases due to a cause such as deterioration of the machine due to age. |
Friction estimation by using the machine diagnosis function
In order to estimate the friction by using the machine diagnosis function, the machine must be operated at high speed as well as at low speed for at least 150 seconds.
Operation at high speed is the range that the motor speed absolute value is greater than or equal to the value of parameter PF31; operation at low speed is the range that the motor speed absolute value is less than the value of parameter PF31. (See Figure 1) In the case of the operation pattern shown in the Figure 1, if for the forward direction friction estimation (a)+(c) is more than 150 seconds and (b) is also more than 150 seconds, a friction estimation result can be obtained.
In the system that the operation speed does not exceed the value of parameter PF31, friction estimation can be performed by changing the value of parameter PF31. When the value of parameter PF31 is zero, the value half of the rated speed is the threshold value at high/low speed operation.
As stated above, friction estimation requires acceleration and deceleration of machine operation speed. When performing speed control or torque control, the speed is always kept constant so that friction estimation may not be performed.
- * PF31: Machine diagnosis function - Friction judgment speed
- * For the details of the machine diagnosis function, please refer to MR Configurator2 Help.
Without a personal computer, GOT can be used to predict the deterioration of the machine.
