Yaskawa Sigma-5 User Manual: Design and Maintenance - Linear Motors - Manual (Page 152)

5 Adjustments
5.1.4 Safety Precautions on Adjustment of Servo Gains
5-8
5.1.4 Safety Precautions on Adjustment of Servo Gains
Yaskawa recommends that the following protective functions of the SERVOPACK are set to the correct set-
tings before starting to adjust the servo gains.
(1) Overtravel Function
Set the overtravel function. For details on how to set the overtravel function, refer to 4.2.3 Overtravel.
(2) Force Limit
Calculate the force required to operate the machine. Set the force limits so that the output force will not be
greater than required. Setting the force limits can reduce the amount of shock applied to the machine in colli-
sions and other cases.
If the force is set below the level of force required to operate the machine, overshooting or vibration may
occur.
Refer to 4.4 Limiting Force for details.
(3) Excessive Position Error Alarm Level
The excessive position error alarm is a protective function that will be enabled when the servo drive is used in
position control mode.
For the optimum setting, the servomotor will be stopped after the error occurs if the servomotor performs
unpredictably after receiving a reference.
The position error is the difference between the position reference and the actual position.
The position error can be calculated with the following equation.
• Excessive Position Error Alarm Level (Pn520 [reference unit])
Set the level to a value that satisfies these equations, and no excessive position error alarm will be generated
during normal operation. The linear servomotor will be stopped, however, if the servomotor runs unpredict-
ably after a reference is input. At the end of the equation, a coefficient is shown as “ × (1.2 to 2). ” This coeffi-
cient is used to add a margin that prevents a faulty alarm from occurring in actual operation of the linear
servomotor.
If the acceleration/deceleration of the position reference exceeds the capacity of the linear servomotor, the lin-
ear servomotor cannot move at the requested speed, and the position error will be increased as not to satisfy
these equations. If so, lower the level of the acceleration/deceleration for the position reference so that the lin-
ear servomotor can move at the requested speed or raise the allowable level of the position errors.
CAUTION
• If adjusting the servo gains, observe the following precautions.
• Do not touch the movable section of the linear servomotor while the linear servomotor power is ON.
• Before starting the linear servomotor, make sure that the emergency-stop circuit works correctly.
• Make sure that a trial operation has been performed without any trouble.
• Install a safety brake on the machine.
Position Error =
Max. feed speed [reference unit/s]
Pn102
Pn520 㧪
˜ (1.2 to 2)
Max. feed speed [reference unit/s]
Pn102