Programming And Activating Handwheel Override - Siemens SINUMERIK 840D Function Manual

For the path input, depending on the traversing direction, the appropriate interface signals are
output to the PLC:
● Machine axes:
– DB31, ... DBX64.6 / 7 (travel command "minus"/"plus")
● Geometry axes:
– DB21, ... DBX40.6 - 7 (geometry axis 1: Travel command "minus"/"plus")
– DB21, ... DBX46.6 - 7 (geometry axis 2: Travel command "minus"/"plus")
– DB21, ... DBX52.6 - 7 (geometry axis 3: Travel command "minus"/"plus")
Limitations
The axial limitations (software limit switch, hardware limit switch, working area limitation) are
effective in conjunction with handwheel override. With path default, the axis can be traversed
with the handwheel in the programmed traversing direction only as far as the programmed
target position.
The resulting velocity is limited by the axial machine data:
MD32000 $MA_MAX_AX_VELO(maximum axis velocity)
NC Stop/override = 0
If the feedrate override is set to 0% or an NC Stop is initiated while the handwheel override is
active, the following applies:
● For path definition:
The handwheel pulses arriving in the meantime are summated and stored. If NC Start or the
feedrate override > 0%, the saved handwheel pulses become effective (i.e. are traversed).
However, if the handwheel is first deactivated [via IS DB21, ... DBX12/16/20.0-2 (geometry
axes 1/2/3: Activate handwheel)] then the stored handwheel pulses are deleted.
● For velocity specification:
The handwheel pulses arriving in the meantime are not summated and are not active.
17.13.1.2

Programming and activating handwheel override

General
When the handwheel override is programmed with NC language elements FD (for path axes)
and FDA (for positioning axes), the following points must be observed:
● FDA and FD function non-modally.
Exception for positioning axes: If traverse instruction POSA is programmed, the handwheel
override can also act modally because this positioning axis does not affect the block
transition.
● When the handwheel override is activated with FDA or FD, a target position must be
programmed in the NC block for the positioning axis or for a path axis. When the
programmed target position is reached, the handwheel override becomes inactive again.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
H1: Manual traversing
17.13 Use of handwheels in automatic mode
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