YASKAWA E-V Series User Manual page 111

5 Adjustments
5.1.4 Safety Precautions on Adjustment of Servo Gains
(1) Overtravel Function
Set the overtravel function. For details on how to set the overtravel function, refer to 4.3.2 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.
Use the following parameters to set the force limits.
Pn483: Forward Force Limit [%]
Pn484: Reverse Force Limit [%]
(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.
Position Error =
Note: Pn102: Position Loop Gain [0.1/s]
• Excessive Position Error Alarm Level (Pn520 [reference unit])
Pn520
Set the level to a value that satisfies these equations, and no alarm will be generated during normal operation.
The servomotor will be stopped, however, if the servomotor runs unpredictably after a reference is input or if
a position error in accordance with the value set in Pn520 occurs. At the end of the equation, a coefficient is
shown as
actual operation of the servomotor.
If the acceleration/deceleration of the position reference exceeds the capacity of the servomotor, the servomo-
tor cannot perform at the requested speed, and the allowable level for 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 servomotor can perform at the requested speed or raise the allowable level of the position errors.
Related Parameter
Excessive Position Error Alarm Level
Setting Range
Pn520
1 to 1073741823
Related Alarm
Alarm
Display
A.d01
A.d02
These alarms will be occur if the number of position error pulses accumulated before the servo turns ON is
greater than the setting of Pn526 (Excessive Position Error Alarm Level at Servo ON).
When an alarm occurs, refer to 8 Troubleshooting and take the corrective actions.
5-8
Motor Speed [min ]
60
Max. Motor Speed [min ]
60
× (1.2 to 2).
This coefficient is used to add a margin that prevents a faulty alarm from occurring in
" "
Setting Unit
1 reference unit
30
(2 -1)
Alarm Name
Position Error Pulse
Overflow Alarm at Servo
ON
Position Error Pulse
Overflow Alarm by
Speed Limit at Servo ON
-1
Number of Pulses per Motor Rotation [reference unit]
-1
Number of Pulses per Motor Rotation [reference unit]
×
Position
Factory Setting
5242880
If the servomotor runs without clearing the position error pulses while the
servo is OFF, excessive position error pulses are accumulated.
If the servo turns ON with position error pulses accumulated, the speed is
limited by Pn584. In this state, the position reference is input without reset-
ting the speed limit, and the position error pulses exceeds the value set for
the parameter Pn520.
Pn102 / 10
Pn102 / 10
When Enabled
Immediately
Alarm Contents
(1.2 to 2)
Classification
Setup