Siemens SINUMERIK 840DE Programming Manual page 278

Feedrate Control and Spindle Motion
7.9 Feedrate with handwheel override (FD, FDA)
Requirements
A handwheel must be assigned to the axes to be traversed for the handwheel override
function. For the precise approach see HMI Operator's Guide. The number of handwheel
pulses per graduated position is defined in machine data.
Traverse path axes with handwheel override, FD
The following preconditions apply to handwheel overrides for path axes:
in the NC block with the programmed handwheel override
• a G1, G2 or G3 motion command must be active,
• exact stop G60 must be switched on, and
• the path feedrate must be specified with G94 mm/min or inch/min.
Feed override
The feed override acts only on the programmed feed, not on the travel movement generated
by the handwheel (except if feed override = 0).
Example:
N10 G1 X... Y... F500...
N50 X... Y... FD=700
The feedrate is accelerated to 700 mm/min in block N50. The path velocity can be increased
or reduced according to the direction of rotation on the handwheel.
Note
It is not possible to traverse in the opposite direction.
Handwheel travel with path default for positioning axes, FDA[axis]=0
In NC blocks with programmed FDA[axis]=0, the feed is set to zero in order that the program
does not generate any travel movement. The programmed travel movement to the target
position is now controlled exclusively by the operator rotating the handwheel.
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Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
Fundamentals