Yaskawa SGDB - Manual (Page 106)

APPLICATIONS OF Σ-SERIES PRODUCTS
3.2.8 Using Torque Feed-forward Function
94
3.2.8 Using Torque Feed-forward Function
For speed control (analog reference) only.
The torque feed-forward function reduces positioning time. It differentiates a speed refer-
ence at the host controller (prepared by the customer) to generate a torque feed-forward
reference, then sends this torque feed-forward reference and the speed reference to the
SERVOPACK.
Too high a torque feed-forward value will result in overshoot or undershoot. To prevent
this, set the optimum value while observing system response.
Connect a speed reference signal line and torque feed-forward reference signal line from
the host controller to V-REF (1CN-5, 1CN-6) and T-REF (1CN-9, 1CN-10), respectively.
Host controller SERVOPACK
Differen
tiation
Position
reference
Current
loop
Servomotor
Speed
calculation
Frequency
dividing
Encoder
KP: Position loop gain
KFF: Feed-forward gain
Schematic Block Diagram for Torque Feed-forward Control
Integration
(Cn-05)
J How to Use Torque Feed-forward Function
To use the torque feed-forward function, set the following memory switch to 1.
Cn-02 Bit 9
Selection of Torque
Feed-forward Function
Factory
Setting: 0
For Speed/Torque Control
Only
Enables the torque feed-forward function.
To use the torque feed-forward function, input a speed reference to the V-REF terminal
and a torque feed-forward reference to the T-REF terminal.
The host controller must generate a torque feed-forward reference.
Setting Meaning
0 Does not use the torque feed-forward function.
1 Uses the torque feed-forward function.
3