Select the desired closed loop Bandwidth (cut-off frequency value of the closed loop frequency response)
according to the dynamic performances requirements of the application (Low = 50 Hz, Medium = 75 Hz, High =
100 Hz).
- High bandwidth means short response time of the servo loop and high gain values.
- Low bandwidth means larger response time of the servo loop and lower gain values.
Before executing the Auto-tuning procedure, check that the motor shaft is free and that its rotation over one
revolution is not dangerous for operator and machine. Check also that the brake is released (the Auto-
tuning command does not control the brake).
After the Auto-tuning, in case of loud noise in the motor at standstill or when running, check the rigidity of the
mechanical transmission between motor and load (backlashes and elasticity in motor and couplings). If required,
start a new Auto-tuning procedure by selecting a lower Bandwidth. If the instability remains, start a new Auto-
tuning procedure by activating the Anti-resonance filter. If necessary, adjust more accurately the loop response
stability by adjusting the Gain scaling factor.
In case of loud noise in the motor, only when running, during the acceleration and deceleration phases, set
Feedforward acceleration gain value at 0.
In the case of an axis with vertical load, proceed as follows:
- Select the Limiting current limitation mode (in order to avoid the drive being disabled in case of an I²t protection
release).
- Initialize the speed loop gains corresponding to the unloaded motor (execute therefore the Auto-
tuning procedure with the motor uncoupled from its mechanical load).
- Couple the motor to its load. If possible, make a control in speed mode; otherwise, close the position loop with a
stable gain.
- Move the axis until a stall position where one motor revolution is not dangerous for operator and machine (far
enough from the mechanical stops).
- Then execute the Auto-tuning procedure with the motor at standstill. If the axis is moving, the Auto-tuning
procedure has not been accepted by the drive.
Regulator gains
Speed loop gains are the most critical to adjust because they greatly depend on the mechanical load
characteristics (inertias, frictions, coupling stiffness, resonances,..).
- Proportional speed gain (KPv): defines the proportional gain of the controller which acts on the speed error.
The higher this parameter value, the faster the speed loop response.
- Integral speed gain (KIv): defines the integral gain of the controller which acts on the speed error. The higher
this parameter value, the better the axis stiffness.
- Integrator low frequency limit (KIvf in Hz): defines the low frequency value from where the controller
integrator term is saturated. This parameter is used for reducing the motor heating in applications with large dry
frictions due to the mechanical load.
- Damping gain (KCv): defines the proportional gain of the controller which acts only on the speed feedback.
This parameter allows reducing the speed loop overshoot in response to a step-like set point change.
- Derivative speed gain (KDv): defines the derivative gain of the controller which acts on the speed error.
- Derivator high frequency limit (KDvf in Hz): defines the high frequency value from which the controller
derivative term is saturated.
- Gain scaling factor (KJv): defines a multiplying factor for all speed regulator gains. This parameter scales the
speed regulator gains in order to avoid any saturation when high values are required. This parameter also allows
adjusting the servo loop stability in case of load inertia changes.