Torque feed-forward function, External speed limit function, Principle of speed limit – Yaskawa FSP Amplifier User Manual

Page 107

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FSP Amplifier User’s Manual

Chapter 5: Parameter Settings and Functions

5-40

The maximum speed of the servomotor will be used if Pn407 is set to a
value higher than the maximum speed of the servomotor.

External Speed Limit Function:

This function sets the voltage range for speed reference input V-REF
(CN1-5) according to the output range of the host controller or external
circuit.
When the default setting (600) is multiplied by 0.01 V, the result (6 V)
corresponds to the rated motor speed.

Parameter Signal

Setting (0.01 V / Rated

Motor Speed)

Control Mode

Pn300

Speed Reference
Input Gain

Range: 150 to 3000
Default Setting: 600

Speed Control and
Programming

The default setting is 6 V = the rated motor speed.

Principle of Speed Limit

When the control speed range is exceeded, the torque, which is inversely
proportional to the difference between the speed limit and the actual speed,
is fed back in order to return the system to a level within the control speed
range. In effect, the actual motor speed limit depends on the load condition.

Motor

speed

V-REF

Speed limit

range

5.2.8. Torque Feed-Forward Function

The torque feed-forward function is used only in speed control (analog
reference). This function is used to:
• Shorten positioning time

• Differentiate a speed reference at the host controller to generate a

torque feed-forward reference

• Input this reference together with the speed reference to the servo

amplifier

Too high a torque feed-forward value will result in an overshoot or an
undershoot. To prevent this, set the optimal value while closely observing
the system response.
Connect a speed reference signal to V-REF (CN1-5 and 6) and a torque
feed-forward reference signal to T-REF (CN1-9 and 10).

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