Mitsubishi Electric A800 Plus Series Function Manual page 205

Application examples
10.4.2
Dancer feedback speed control with roll diameter
compensation for wire drawing machines
This is useful for winding wire using a wire drawing machine.
The dancer feedback speed control with roll diameter compensation function in the inverter enable high-speed winding for
high-inertia loads.
Requirements for this application
High-speed winding for high-inertia loads and the stability of a dancer roll are required in this application.
Purpose
Stability of dancer roll
Winding for high-inertia loads
Cost reduction
Control overview
The wire drawing section pulls the wire at a constant speed to make the wire thinner. Tension of wire to be wound is
maintained constant by the dancer roll. For the winding roller (shaft), the inverter provides dancer feedback speed control to
keep the dancer roll position, achieving constant tension winding. In addition, using the roll diameter compensation function,
the circumferential speed of the winding bobbin is kept constant.
FR-A800-R2R inverters have the following additional functions as compared with the FR-A800 inverter standard models.
Additional function
Dancer feedback speed control
function
Roll diameter compensation function
Tension PI gain tuning
Speed control proportional gain
compensation function
SF-
V5RU
FR-A800-R2R
2
FR-A8AP
Line speed setting
(0 to 10V)
Encoder
Brake
unit
Brake
resistor
For intermediate
roller
204
APPENDIX
The inverter minimizes speed fluctuation to prevent sagging and unevenness.
Higher responsivity can be expected under Vector control using encoders (internal response: 300 rad/s).
A dancer roll controller is included in the inverter.
The winding roller rotation speed is controlled to keep the dancer roll position constant.
After the winding roll diameter is calculated, the motor speed is controlled based on data of the
diameter so that circumferential speed of the winding roll are kept constant. This function reduces
hunting in dancer feedback speed control. Roll diameter calculators and PID calculators do not
need to be added externally.
By automatically adjusting the tension PI gain for dancer PID control, time required for adjustment
is significantly cut down. Anyone can start the system easily.
Speed control proportional gain can be changed based on the value determined by roll diameter
calculation.
Dancer Dancer
signal signal
Encoder Encoder
SF-
V5RU
FR-A800-R2R
2
FR-A8AP
1 1
Brake
unit
Brake
resistor
For intermediate For intermediate
roller roller (reference axis)
Feature of inverter
Description
Encoder
SF-
V5RU
potentiometer
FR-A800-R2R
2
FR-A8AP
Dancer/tension control selection (X114)
AM
Brake
unit
Brake
resistor
Displacement
gauge
Non-contact
Actual line speed
(single phase)
Dancer position
(0 to ±10 V)
Line speed (0 to 10 V)
Encoder
SF-
V5RU
FR-A800-R2R
JOG
1
FR-A8AP
RL
2
Brake
unit
Brake
resistor
For winding roller