ITEM C 3-Series, Руководство по эксплуатации продукта

Страница: 55 / 160

Function overview
Page 55
5.2.5 Speed-controlled mode
This operating mode is used if the motor speed is to be kept constant regardless of the acting load. The motor speed exactly
follows the speed that is defined by the setpoint management system.
The cycle time of the speed control loop for the item Servo Positioning Controller C 3-Series is twice the PWM period, thus
typically 208.4 µs. However, it can also be set as an integer multiple of the current controller cycle time.
The speed controller is a PI controller with an internal resolution of 12 bits per rpm. In order to eliminate wind-up effects, the
integrator function is stopped when subsidiary limits are reached.
In the speed control mode, the current controller and and the speed controller are active. If the setpoints are set via analogue
setpoint inputs, a "safe zero" can be defined as an option. If the analogue setpoint is within this range, the setpoint is set to zero
("dead zone"). This can suppress interferences or offset drifts. The "dead zone" function can be activated and deactivated and
the width can be set.
The actual speed and position are determined by the encoder system inside the motor, which is also used for commutation.
For the actual value feedback for speed control, any encoder interface may be selected (e.g. a reference encoder or a
corresponding system at the external incremental encoder input). The actual speed value for the speed controller is then fed
back, e.g. via the external incremental encoder input.
The speed setpoint can be set internally or it can be derived from the data of an external encoder system (speed
synchronisation via [X10] for the speed controller).
5.2.6 Torque-limited speed control
The item Servo Positioning Controller C 3-Series support torque-limited, speed-controlled operation with the following features:

Fast updating of the limit value, e.g. in a 200 µs cycle

Addition of two sources of limitation (e.g. for servo control values)
5.2.7 Synchronisation with external clock signals
The controllers use sinusoidal constrained current operation. The cycle time is always bound to the PWM frequency. In order
to synchronise the device control with external clock signals (e.g. CANopen, EtherCAT), the device has a corresponding PLL.
Accordingly, the cycle time varies within certain limits to enable the synchronisation with the external clock signal. For the
synchronisation with an external clock signal, the user must enter the nominal value of the synchronous cycle time.
5.2.8 Load torque compensation in the case of vertical axes
For vertical axis applications, the holding torque at standstill can be determined and stored. It is then added to the torque
control loop and improves the start-up behaviour of the axes when the holding brake is released.
5.2.9 Positioning and position control
In the positioning mode, a superordinate position controller is active in addition to the speed control. It processes the
deviations between the actual position and set position and converts them into the corresponding setpoints for the speed
controller.