Safety Precautions On Adjustment Of Servo Gains - YASKAWA JUSP-MD D01A Series User Manual

6 Adjustments

6.1.4 Safety Precautions on Adjustment of Servo Gains

6.1.4

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 multi-winding drive unit can come to an emergency stop at any
• 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 multi-winding drive unit to the correct settings 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 5.2.3 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 5.8 Limiting Torque.
(3) Excessive Position Error Alarm Level
The excessive position error alarm is a protective function that will be enabled when the multi-winding drive
unit is used in position control.
If this alarm level is set to a suitable value, the multi-winding drive unit 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 5.4.4 Electronic Gear.
∗2. When model following control is enabled (Pn140 is set to n.1), use the set value of Pn141 and not that of
Pn102.
∗3. To check the Pn102 setting, change the parameter display setting to display all parameters (Pn00B.0 = 1).
∗4. At the end of the equation, a coefficient is shown as "× (1.2 to 2)." This coefficient is used to add a margin that pre-
vents a position error overflow alarm (A.d00) from occurring in actual operation of the servomotor.
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 multi-wind-
ing drive unit detects an excessive position error.
The following calculation example is for a motor with a maximum motor speed of 2,000 and an encoder reso-
lution of 1,048,576 (20 bits). The following settings are used: Pn102 = 400 and Pn210/Pn20E = 1/1.
Pn520
6-8
time.
Max. Motor Speed [min ]
60
2000 1048576 1
× ×
60 400/10 1
873813.3 × 2
1747627
CAUTION
-1
Motor Speed [min ] Encoder Resolution
60 Pn102 [0.1/s]/10
-1
*1
Encoder Resolution
×
*2, *3
Pn102 [0.1/s]/10
×
2
*1 Pn210
*2, *3
Pn20E
Pn210
× (1.2 to 2)
×
*4
Pn20E
Rotation
Rotation