Mitsubishi Electric MELSERVO-J4 series, Instruction Manual

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14 USING A LINEAR SERVO MOTOR
14.3 Operation and functions
Auto tuning function
The auto tuning mode 1 may not be performed properly if the following conditions are not satisfied.
• Time to reach 2000 mm/s is the acceleration/deceleration time constant of 5 s or less.
• The linear servo motor speed is 150 mm/s or higher.
• The load to mass of the linear servo motor primary-side ratio is 100 times or less.
• The acceleration/deceleration thrust is 10% or less of the continuous thrust.
Although the auto tuning function during the linear servo motor operation is the same as that of the rotary servo motor, the
calculation method of the load to motor mass ratio (J ratio) is different. The load to motor mass ratio (J ratio) on the linear
servo motor is calculated by dividing the load mass by the mass of the linear servo motor primary side.
Ex.
Mass of linear servo motor primary side = 2 kg
Load mass (excluding the mass of the linear servo motor primary side) = 4 kg
Mass ratio = 4/2 = 2 times
For the parameters set with the auto tuning function, refer to the following.

Page 227 NORMAL GAIN ADJUSTMENT
Machine analyzer function
• Make sure to perform the machine analyzer function after the magnetic pole detection. If the magnetic pole
detection is not performed, the machine analyze function may not operate properly.
• The stop position at the completion of the machine analyzer function can be arbitrary.
Absolute position detection system
When the linear servo motor is used with the absolute position detection system, an absolute position linear encoder is
required. The linear encoder backs up the absolute position data. Therefore, the encoder battery need not be installed to the
servo amplifier. Additionally, [AL. 25 Absolute position erased], [AL. 92 Battery cable disconnection warning], [AL. 9F Battery
warning], and [AL. E3 Absolute position counter warning] are not provided for the linear servo motor.