Technical data

Technology functions
CPU 317T: Technology Functions
A5E00251798-03
6-83
Velocity-controlled operation of a positioning axis
The transition "position-controlled motion" to "motion control with velocity preset"
and vice versa can be set not only when the axis is in standstill, but also when it is
in RUN.
You can use input parameters PositionControl to set either position or velocity
control for position-controlled axes.
In velocity-controlled mode with velocity preset 0, the axes can be ramped down
immediately, even if a greater following error has developed at the axis as a result
of torque limiting, for example.
Software limit switch monitoring stays active.
Note
Velocity-controlled operation is maintained until one of the following positioning
commands is started:
• MC_MoveAbsolute
• MC_MoveRelative
• MC_MoveAdditive
• MC_MoveVelocity (when PositionControl = TRUE)
• MC_MoveToEndPos
• MC_GearIn
• MC_CamIn
Restrictions with active velocity control:
• Homing not possible (MC_Home)
• The axis must be enabled for position control in order to operated in master
mode with setpoint coupling. When PositionControl = FALSE, the setpoint
position of the axis is held constant.
Note
If the user program causes a velocity-controlled axis to overtravel a SW limit
switch, you first need to disable this switch in order to release the axis.
If the user program does not support disabling of limit switches, you have to cycle
power off and on in order to reset position control mode at the axis. You can then
release the axis.