Siemens SINUMERIK 840D sl Programming Manual page 542

Path traversing behavior
8.3 Program sequence with preprocessing memory (STOPFIFO, STARTFIFO, FIFOCTRL, STOPRE)
Significance
STOPFIFO:
STARTFIFO:
FIFOCTRL:
STOPRE:
Note
The preprocessing memory is not filled or filling is interrupted if the machining step contains
commands that require unbuffered operation (search for reference, measuring functions,
etc.).
Note
The control generates an internal preprocessing stop in the event of access to status data
($SA...).
If tool offset or spline interpolations are active, a STOPRE command should not be
programmed, as this will lead to contiguous block sequences being interrupted.
Example: Stop preprocessing
Program code
...
N30 MEAW=1 G1 F1000 X100 Y100 Z50
N40 STOPRE
...
542
STOPFIFO identifies the start of a machining step to be buffered in the
preprocessing memory. STOPFIFO stops processing and fills the
preprocessing memory until:
• STARTFIFO or STOPRE is detected
or
• The preprocessing memory is full
or
• The end of the program is reached
STARTFIFO starts rapid processing of the machining step; the
preprocessing memory is filled in parallel to this.
Activation of automatic preprocessing memory control
Stop preprocessing
CAUTION
Comment
; Measurement block with probe at first
measuring input and linear
interpolation.
; Preprocessing stop.
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
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