Feedrate With Handwheel Override (Fd, Fda) - Siemens SINUMERIK 840D sl Programming Manual

In the part program
The value written in the part program is then only taken into consideration in system variable
$AA_ACC as written in the part program if ACC was not changed in the meantime by a
synchronized action.
In synchronized actions
The following therefore applies: The value written to a synchronized action is then only
considered in system variable $AA_ACC as written to the synchronized action if ACC was not
changed in the meantime by a part program.
The specified acceleration can also be changed using synchronized actions.
Example:
Program code
...
N100 EVERY $A_IN[1] DO POS[X]=50 FA[X]=2000 ACC[X]=140
The actual acceleration value can be called with system variable $AA_ACC[<Axis >] Machine
data can be used to determine whether the ACC value last set should apply on RESET/parts
program end or whether it should be set to 100%.
2.7.8

Feedrate with handwheel override (FD, FDA)

The FD and FDA commands can be used to traverse axes with handwheels during execution
of the part program. The programmed settings for traversing the axes are then overlaid with the
handwheel pulses evaluated as path or velocity inputs.
Path axes
In the case of path axes, the programmed path feedrate can be overlaid. The handwheel is
evaluated as the 1st geometry axis of the channel. The handwheel pulses evaluated per
interpolation cycle, dependent on the direction of rotation, correspond to the path velocity to be
overlaid. The path velocity limit values which can be achieved by means of handwheel override
are:
● Minimum: 0
● Maximum: Machine data limit values of the path axes involved in traversing
Note
Path feedrate
The path feedrate F and the handwheel feedrate FD cannot be programmed in the same NC
block.
NC programming
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
Fundamentals
2.7 Feed control
127