Application examples
208
10.4.3
Tension sensorless torque control with roll
diameter compensation for printers
This is useful for winding paper rolls for printers.
Torque control by the inverter with tension control, inertia compensation, and mechanical loss compensation enables the
winding of paper rolls without dancer rolls and tension controllers.
Requirements for this application
This control method is suitable for a winding application where a reasonable finish is required in about half the dancer-roll-
winding machine speed.
Control overview
The FR-A800-R2R inverter is used for a winding roller.
The inverter controls the motor output torque according to the calculated diameter of a paper roll to make paper tension
constant.
When the paper feed speed of the printer is increased (or decreased), the inverter changes the torque command value
according to the inertia of the paper roll to give the acceleration (or deceleration) torque to keep a constant tension. A taper
ratio can be also set to prevent the roll from getting too tight.
FR-A800-R2R inverters have the following additional functions as compared with the FR-A800 inverter standard models.
∗1
To make the tension constant, the torque is controlled according to the changing roll diameter.
Motor torque (T) = Tension (F) × Roll diameter (D) / 2
Purpose
Feature of inverter
Cost reduction
Dancer rolls and tension controllers are not required for the winding system (tension control).
Constant tension
Tension is kept steady during operation including acceleration/deceleration (by inertia compensation
and mechanical loss compensation).
Additional function
Description
Roll diameter calculation function,
tension control
The inverter controls the motor output torque according to the changing diameter of a paper roll to
make paper tension constant.
Taper function
Tension is reduced when the roll diameter increases in order to prevent the roll from getting too
tight. Various taper ratio settings are enabled using parameters.
Inertia compensation function
Paper tension is kept constant by adding the acceleration/deceleration torque even when the
paper feeding speed increases/decreases.
Mechanical loss compensation
function
The torque command, which is calculated in consideration of the mechanical loss amount, is given
to avoid tension changes due to mechanical losses.
FR-A800-R2R
X112
X114
STF/STR
Nip roll
Tension (F)
∗1
X111
Speed limit
Start command
1
Tension command
FR-A8AZ
For intermediate roller
For winding roller
Inertia compensation deceleration signal
6
Dancer/tension control selection
Encoder
FR-A8AP
Roll diameter
(D)
Torque (T)
Inertia compensation acceleration signal
X109
Stored winding diameter clear signal
Stall mode trigger signal
X123
2
Line speed
SF-
V5RU
FR-A800-R2R
Encoder
FR-A8AP
AM
Y237
Y238
SF-
V5RU
X114
Dancer/tension control
selection
Printing
unit
Summary of Contents for A800 Plus Series
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