Diameter Calculation; Diameter Hold - ABB ACS880 Firmware Manual

Diameter calculation

This function provides the means of control over the roll diameter calculation process.
There are several options on how the diameter value can be acquired:
• The diameter sensor feedback signal can be wired either directly to the drive
analog input or sent remotely through a fieldbus.
• When no sensor is available, the control program can estimate the actual roll
diameter using the ratio between line surface speed feedback and the actual
motor speed. To stabilize the calculation, the actual diameter rate of change is
limited according to the web thickness setting.
• Alternatively, actual diameter can also be derived from the number of revolutions
by an encoder installed either on the motor/roll shaft or on the line pulley. For
more details, see
The program uses actual diameter signal for calculating motor speed and torque
reference, as well as estimating the roll weight. The diameter value can be reset to its
core diameter value or to the full roll diameter value, depending on the selected
winding mode (winder or unwinder) and also can be preset to a user-defined value.
See control chain diagram for


Diameter hold

Diameter hold function observes the cases when diameter should not be calculated.
Diameter hold status is shown when the following hold conditions are met:
• drive is stopped
• both count up and count down are disabled
• when PID control is disabled
• when torque memory is active
• actual speed and actual tension is less than the minimum
• jogging mode is active
• full roll diameter is reached
• diameter reset or preset is active
• web thickness is less than the minimum
• parameter 76.07 Hold diameter count
Note: For NIP or pinch roll (infeeder) the diameter of the driven roll does not change,
so diameter calculation must be disabled by setting the core and maximum diameter
to same value (empty roll diameter).
Settings
Parameter group 76 Diameter calculation
Virtual roll function on page 61.
Diameter calculation
Winder program features 49
on page 663.
input is active.
(page 425)