Siemens SINUMERIK Series Function Manual page 172

H1: Manual and handwheel travel
3.5 Handwheel override in automatic mode
Velocity override
With regard to the velocity override, a distinction is made between axis feedrate and path
feedrate.
● Axis-velocity override (FDA[AXi] > 0):
● Path-velocity override (FD > 0):
Application example
The "Handwheel override in automatic mode" function is frequently used on grinding
machines. For example, the user can position the reciprocating grinding wheel on the
workpiece using the handwheel (path default). After scratching, the traversing movement is
terminated and the block change is initiated (by activating DB31, ... DBX2.2 (delete distance-
to-go)).
Preconditions
In order to activate "Handwheel override in automatic mode", the following requirements
must have been met:
● A handwheel must be assigned to the axis in question.
● Pulse weighting exists for the assigned handwheel.
172
The positioning axis is moved to the target position at the programmed axial feedrate.
Using the assigned handwheel, it is possible to increase the axis velocity or to reduce it to
a minimum of zero depending on the direction of rotation. The resulting axis feedrate is
limited by the maximum velocity. However, the axis cannot be traversed in the opposite
direction to that programmed.
The block change is performed as soon as the axis reaches the programmed target
position. This causes the velocity override to be deactivated automatically and any further
handwheel pulses have no effect.
Similarly, this also applies to concurrent positioning axes, where the target position and
the velocity are defined by the PLC.
The path axes programmed in the NC block traverse to the target position at the
programmed feedrate. If the velocity override is active, the programmed path velocity is
overridden by the velocity generated with the handwheel of the 1st geometry axis. The
block change is performed as soon as the programmed target position is reached.
The path velocity is increased or reduced to a minimum of zero depending on the
direction of rotation of the handwheel. However, it is not possible to reverse the direction
of movement with handwheel override.
Function Manual, 03/2013, 6FC5397-1BP40-3BA1
Extended Functions