5-19
5-1-4 Explanation of User Parameters
Refer to
3-4-2 Setup Parameter Contents and 3-5-2 User Parameter Chart for a table of user parame-
ters and setup parameters.
D
Speed Loop Gain: Cn-04
This is the proportional gain for the speed controller. The adjustable range is 1 to 2,000 Hz (the response
frequency when equivalent inertia is used). As the number is increased, the gain is increased.
The factory setting is for 80 (Hz). Using the factory setting for the Servomotor alone or with a small load
inertia will cause vibration to occur, so set the value to a maximum of 20 (Hz) for operation.
D
Speed Loop Integration Constant: Cn-05
This is the integration time for the speed controller. The adjustable range is 2 to 10,000 (ms), and it is
factory set to 20 (ms). As the number is increased, the gain is decreased.
D
Brake Timing: Cn-12
These parameters determine the output timing of the brake interlock signal (BKIR), which controls the
electromagnetic brake.
Brake timing sets the delay time from the time of brake interlock goes OFF until the servo turns off.
A dynamic brake will be applied when the Run command turns OFF while the motor is operating, when a
servo error occurs, or when power is turned off. The brake interlock output (BKIR) will turn OFF when
the motor speed is reduced to 100 r/min or less. The brake interlock output (BKIR) will also turn OFF if
power is not supplied to the motor for 500 ms even if the motor speed is greater than 100 r/min.
This setting is used to prevent destroying the holding brake on the servomotor or the machine.
D
Torque Command Filter Time Constant: Cn-17
This sets the low-pass filter time constant for the torque command. The setting range is 0 to 250 (
×
100
µ
s), and the factory setting is 4 (
×
100
µ
s).
The relationship between the filter time constant and the cut-off frequency can be found by means of the
following formula:
fc (Hz) = 1 / (2
πΤ
)
:
Τ
= Filter time constant
If
Τ
= 400 (
µ
s), fc will be approximately 400 (Hz).
When the characteristic vibration of the machinery is within the response frequency of the servo loop,
Servomotor vibration will occur. In order to prevent this sympathetic vibration based on the characteris-
tic vibration of the machinery, set the torque filter time constant to a value that will eliminate the vibration
(i.e., set it to a high value).
D
Position Loop Gain: Cn-1A
Adjust the position loop gain to the rigidity of the machine. Set to between 50 and 70 (1/s) for general NC
machine tools, to between 30 and 50 (1/s) for general and assembly machines, and to 10 to 30 (1/s) for
industrial robots.
Load alarms will be caused by machine oscillation if the position loop gain is increased for systems with
low rigidity or systems with intrinsically low-frequency vibration.
Specifications
Chapter 5
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