Cleveland Motion Controls Quantum Tension Controller REV A - Manual (Page 27)

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5.0 Menu PID
5.1 Coefficients Menu
This menu is available for both closed loop and inertia compensation configurations.
5.2 Closed loop + Open loop Control function
When using a closed loop configuration, this function allows integration with an open loop control by using
a specific coefficient for each of these control modes; open loop gain and closed loop gain. This function
allows additional closed loop control around the result of an open loop control, in order to limit the Measure
- Set point difference, to improve the system stability as well as the accuracy.
Calculation - Open loop gain CBO
DATA :
Max Force range F (N)
Max web diameter D (m)
Rated current for the chosen Brake IC (A)
Max current adjusted on the power supply board IR (A)
Rated torque for the chosen Brake CN (Nm)
Formula: CBO = F x D x IC x 100
2 x CN x IR
The result gives the open loop true coefficient. This value can be modified to optimize the system stability.
5.3 Inertia compensation function
The Inertia compensation function allows an additional open loop control to the calculated currrent closed
loop result during the acceleration/deceleration periods. This coefficient (inertia gain) is related to the roll
inertia (proportional to the actual diameter measurement) and to the actual line speed (tachometer input).
When the Web width is not constant, it is possible to adjust the calculated inertia term by entering the
coefficient Web width (also available to the operator on the controller front panel).
Calculation - Inertia gain GI:
Data:
Max roll weight M ( Kg )
Max roll diameter D ( m )
Max line speed VL ( m/s )
Decceleration duration T ( s )
Rated current for the chosen Brake IC ( A )
Max current adjusted on the power supply board IR ( A )
Rated torque for the chosen Brake CN ( N.m )
Formula: GI = M x VL x D x IC x 100
240 x T x CN x IR
Adjustment procedure:
Proceed with the first tests with the maximum Web width (Coeff. Web width = 100%). Temporarily
disable the open loop control (Closed loop gain = 0 %) to avoid interactions during the adjustment
procedure. Apply a high filtering coefficient on the diameter input (slow variation input): Diameter
filtering = 500. Enter a low filtering coefficient on the Tachy measurement input to avoid fast transient
troubles. Apply the calculated Inertia gain (above formula). Start the machine and adjust the inertia
gain value to stabilize the actual measurement during acceleration/deceleration periods.