Override and Stop

The override is used to change the target velocity of the axis online in the quickest possible way. 
Stop is realized via override 0.0 and has priority over all other functions.

Override

The override is an instantaneous (not time-scaled) override, i.e. an attempt is made to reach the new velocity level as quickly as possible with the maximum permissible changes in acceleration.
The override can be changed from 0.0% to 100.0% in steps of 1/1,000,000.

There are four override types:

  1. The override refers to the target velocity level calculated and possibly reduced at axis start. If the new velocity level is not achievable, the old runtime table is maintained without notification.
  2. The override refers to the target velocity specified by the user. If the new velocity level is not achievable, the old runtime table is maintained without notification. 
  3. The override refers to the target velocity level calculated and possibly reduced at axis start. If the new velocity level is not achievable then an attempt is made to achieve a smaller optimal velocity level. 
  4. The override refers to the target velocity specified by the user.  If the new velocity level is not achievable then an attempt is made to achieve a smaller optimal velocity level. 

The override is only activated if there is no stop and if the brake phase has not yet been reached. There is a possibility to start the axis with override 0%.

In case of excessively quick (especially periodical) changes of the overrides between two fixed velocity levels, the axis, whilst calculated deterministically, will behave indeterministically for the user. 

Notes on the figures:

Scales: velocity [mm/s] / time [s]
Colors: 

            Set position: dark blue                        Actual position: light blue

            Target velocity: dark green        Actual velocity: light green 

            Set acceleration: dark red            Actual acceleration: light red

            Following error: yellow 

 

Override and Stop 1:

 

Override changes: start override 100% -> 75% -> 100% (V = 2000.0 mm/s, from 0.0 mm to 5000.0 mm)

 

Override and Stop 2:

 

Override changes: start override 20% -> 100% (V = 2000.0 mm/s, from 0.0 mm to 5000.0 mm)

Stop 

Stop is realized via override 0.0 and has - provided the brake phase has not yet been reached - priority over all other functions. If stop is requested and position compensation is active, compensation stop is activated simultaneously with the stop of the basic dynamics, in order to stop the axis as quickly as possible on the maximum permissible breaking ramp.

Emergency stop 

In case of an emergency stop with parameters jerk R [mm/s/s/s] and deceleration A- [mm/s/s], the parameters jerk and deceleration are reset, if both parameter are genuinely larger than the parameters provided at the start. The stop is then initiated with the new parameters.

N.B.: in the brake phase (natural or induced by the user) no emergency stop is possible.