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Dancer control with winding diameter
compensation for printers
5 APPLICATION EXAMPLE
5.1 Dancer control with winding diameter compensation for printers
Dancer control is useful for rolling up a sheet of paper of a printer.
A sheet of paper can be rolled up faster and in better quality with dancer control with winding diameter compensation.
(1) Feature
For a system like this, the speed of roll up is important.
Furthermore, fluctuation of dancer roll should be kept minimum to avoid sagging and unevenness of the sheet rolled up.
(2) Outline
FR-A700 series inverter installed in the intermediate shaft controls the line speed of the whole print paper. Dancer roll
regulates the tension applied on the sheet of paper, and wind-up the sheet of paper.
For the rolling shaft, use FR-A700-A1 series inverter with dancer control function. Keep the tension constant while rolling up
the sheet of paper by stabilizing the position of dancer roll with dancer control.
The rim speed of paper is also kept constant by winding diameter compensation function.
The following functions are added to FR-A700-A1 series, compared to FR-A700 series.
Purpose
Feature
Sagging and unevenness prevention
Low percentage of speed fluctuation.
Speed up
Speed response level (internal response is 300rad/s) when vector control with encoder is used.
Cost reduction
Function of dancer roll controller is embedded.
Additional Function
Description
Dancer control function
Controls the speed of wind-up shaft to keep the position of dancer roll steady.
Analog signal output for dancer
control
Tension command for dancer roll is output by analog signal.
Winding diameter compensation
function
Controls rotation speed of motor to keep the rim speed constant by calculating the diameter of wind-
up shaft. By using winding diameter compensation, hunting of dancer control can be suppressed.
Winding diameter compensation and PID calculator are not necessary.
Recording
unit
Encoder
FR-A700 *3
FR-A700-A1
Main speed
setting
2
Encoder
*1
Main speed (0 to 10V)
2
DA1
FR-A7AP
FR-A7AZ
1
Dancer position (0 to 0V)
Dancer/tension control
selection X83
RL
JOG
AM
FM
Winding
diameter monitor
Line speed monitor
FR-A7AP
SF-V5RU
Encoder
SF-V5RU
Line speed
(single-phase
pulse)
Line speed
(single-phase
pulse)
Line speed
(single-phase
pulse)
Reference shaft
Winding shaft
Deviation
sensor
(No-contact
potentiometer)
*2
*1
The main speed is constant, so the winding speed decelerates as the winding diameter increases.
In FR-A700-A1 series, the speed is calculated automatically by winding diameter compensation.
*2
The position of the deviation sensor (no-contact potentiometer) is kept constant by dancer control (PID control), and frequency is compensated.
*3
FR-A700 series with FR-A7AP (vector control with encoder) are used when steady operation to low speed, speed accuracy (small speed
fluctuation), and response speed to stabilize position of dancer roll are necessary.
