Safety Precautions On Adjustment Of Servo Gains - YASKAWA SGMJV User Manual

5 Adjustments

5.1.4 Safety Precautions on Adjustment of Servo Gains

5.1.4

Safety Precautions on Adjustment of Servo Gains

• If adjusting the servo gains, observe the following precautions.
• Do not touch the rotating section of the servomotor while power is being supplied to the motor.
• Before starting the servomotor, make sure that the SERVOPACK can come to an emergency stop at any time.
• Make sure that a trial operation has been performed without any trouble.
• Install a safety brake on the machine.
Set the following protective functions of the SERVOPACK to suitable settings before you start to adjust the
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) Torque Limit
The torque limit calculates the torque required to operate the machine and sets the torque limits so that the out-
put torque will not be greater than required. Setting torque limits can reduce the amount of shock applied to
the machine when troubles occur, such as collisions or interference. If a torque limit is set lower than the value
that is needed for operation, overshooting or vibration can be occurred.
For details, refer to 4.6 Limiting Torque.
(3) Excessive Position Error Alarm Level
The excessive position error alarm is a protective function that will be enabled when the SERVOPACK is used
in position control.
If this alarm level is set to a suitable value, the SERVOPACK will detect an excessive position error and will
stop the servomotor if the servomotor does not operate according to the reference. The position error indicates
the difference between the position reference value and the actual motor position.
The position error can be calculated from the position loop gain (Pn102) and the motor speed with the follow-
ing equation.
Position Error [reference unit] =
• Excessive Position Error Alarm Level (Pn520 [1 reference unit])
Pn520 >
∗1. Refer to 4.4.3 Electronic Gear.
∗2. When model following control is enabled (Pn140 = n.1), use the set value in Pn141 and not in Pn102.
∗3. To check the setting in Pn102, change the parameter display setting to display all parameters (Pn00B = n.1).
∗4. The underlined "(1.2 to 2)" portion is a factor that creates a margin so that a position error overflow alarm (A.d00)
does not frequently occur.
Set the level to a value that satisfies these equations, and no position error overflow alarm (A.d00) will be gen-
erated during normal operation.
The servomotor will be stopped, however, if it does not operate according to the reference and the SERVO-
PACK detects an excessive position error.
The following example outlines how the maximum limit for position deviation is calculated. These conditions
apply.
• Maximum speed = 6000
• Encoder resolution = 1048576 (20 bits)
• Pn102 = 400
Pn210
•
Pn20E
5-8
Motor Speed [min ]
-1
Max. Motor Speed [min ]
×
60
1
=
1
CAUTION
-1
Encoder Resolution
×
60 Pn102 [0.1/s]/10
Pn210
Encoder Resolution *1
×
Pn102 [0.1/s]/10
*2, *3 Pn20E
*1 Pn210
×
Pn20E
*2, *3
× (1.2 to 2)
*4