Siemens SINUMERIK 840Di sl Programming Manual page 291

SPI
Axis
Range of values
Note
The programmed feedrate FA[...] is modal.
Up to 5 feeds for positioning axes or spindles can be programmed in each NC block.
Example of synchronous spindle link
With synchronous spindle link, the positioning speed of the following spindle can be
programmed independently of the master spindle – for example, for positioning operations.
Example: FA[S2]=100
The spindle identifiers SPI(...) and S... are identical in terms of function.
Example of calculating the derived feedrate FPR
The derived feedrate is calculated according to the following formula:
Derived feedrate = programmed feedrate * Absolute master feedrate
Example: Path axes X, Y must be traversed at the revolutional feedrate derived from rotary
axis A:
N40 FPR(A)
N50 G95 X50 Y50 F500
Feedrate FA[...]
The feedrate is always G94. When G70/G71 is active, the unit of measurement is
metric/inches according to the default setting in the machine data. G700/G710 can be used
to modify the unit of measurement in the program.
Notice
If no FA is programmed, the value defined in the machine data applies.
Fundamentals
Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
7.5 Feedrate for positioning axes/spindles (FA, FPR, FPRAON, FPRAOF)
Converts the spindle number into an axis identifier; the transfer
parameter must contain a valid spindle number. SPI is used for the
indirect definition of a spindle number.
Positioning axes or geometry axes
...999 999.999 mm/min, degree/min
...39 999.9999 inch/min
Feedrate Control and Spindle Motion
291