Mitsubishi Electric A800 Plus Series Function Manual page 209

Application examples
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.
Purpose
Cost reduction
Constant tension
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.
Additional function
Roll diameter calculation function,
tension control
Taper function
Inertia compensation function
Mechanical loss compensation
function
Dancer/tension control
selection
X114
For intermediate roller
∗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
208
APPENDIX
Dancer rolls and tension controllers are not required for the winding system (tension control).
Tension is kept steady during operation including acceleration/deceleration (by inertia compensation
and mechanical loss compensation).
The inverter controls the motor output torque according to the changing diameter of a paper roll to
make paper tension constant.
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.
Paper tension is kept constant by adding the acceleration/deceleration torque even when the
paper feeding speed increases/decreases.
The torque command, which is calculated in consideration of the mechanical loss amount, is given
to avoid tension changes due to mechanical losses.
Printing
unit
Encoder
SF-
V5RU
FR-A800-R2R
FR-A8AP
AM
Y237
Y238
Feature of inverter
Description
Inertia compensation acceleration signal
Inertia compensation deceleration signal
Speed limit
Start command
Dancer/tension control selection
Stored winding diameter clear signal
Stall mode trigger signal
Tension command
Nip roll Tension (F)
∗1
Torque (T)
SF-
V5RU
FR-A800-R2R
FR-A8AP
Line speed
2
X111
X112
1
STF/STR
X114
X109
X123
FR-A8AZ
6
For winding roller
Roll diameter
(D)
Encoder