Siemens SINUMERIK 840D sl Function Manual page 298

Manual and Handwheel Travel (H1)
4.5 Handwheel override in automatic mode
Path default
With axis feedrate = 0 (e.g., FDA[AXi] = 0), the traversing movement of the positioning
axis towards the programmed target position is controlled entirely by the user rotating the
assigned handwheel.
The direction in which the handwheel is turned determines the traversing direction of the
axis. The programmed target position cannot be exceeded during handwheel override. The
axis can also be moved toward the programmed target position from the opposite direction,
whereby the movement is only restricted by the axial position limitations.
A block change occurs when:
● The axis has reached the programmed target position
or
● The distance-to-go is deleted by axial interface signal
From this moment on, the path default is deactivated and any further handwheel pulses have
no effect.
After this, incrementally programmed positions refer to the point of interruption and not to the
last programmed position.
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):
298
DB31, ... DBX2.2 (delete distance-to-go).
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 first 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, 01/2008, 6FC5397-1BP10-3BA0
Extended Functions