Siemens Sinumerik 840D sl Programming Manual page 282

Special Motion Commands
4.8 Extended measuring function (MEASA, MEAWA, MEAC) (option)
The FIFO memory is a circular buffer in which measured values are written to $AC_FIFO
variables according to the circular principle, see the chapter titled "Motion-synchronous
actions".
Note
FIFO contents can be read only once from the circulating storage. If these measured data
are to be used multiply, they must be buffered in user data.
If the number of measured values for the FIFO memory exceeds the maximum value defined
in machine data, the measurement is automatically terminated.
An endless measuring process can be implemented by reading out measured values
cyclically. In this case, data must be read out at the same frequency as new measured
values are read in.
Recognized programming errors
The following programming errors are detected and indicated appropriately:
• MEASA/MEAWA programmed with MEAS/MEAW in the same block
Example:
N01 MEAS=1 MEASA[X]=(1,1) G01 F100 POS[X]=100
• MEASA/MEAWA with number of parameters <2 or >5
Example:
N01 MEAWA[X]=(1) G01 F100 POS[X]=100
• MEASA/MEAWA with trigger event not equal to 1/ -1/ 2/ -2
Example:
N01 MEASA[B]=(1,1,3) B100
• MEASA/MEAWA with invalid mode
Example:
N01 MEAWA[B]=(4,1) B100
• MEASA/MEAWA with trigger event programmed twice
Example:
N01 MEASA[B]=(1,1,-1,2,-1) B100
• MEASA/MEAWA and missing GEO axis
Example:
N01 MEASA[X]=(1,1) MEASA[Y]=(1,1) G01 X50 Y50 Z50 F100 ;GEO axis X/
Y/Z
• Inconsistent measuring task with GEO axes
Example:
N01 MEASA[X]=(1,1) MEASA[Y]=(1,1) MEASA[Z]=(1,1,2) G01 X50 Y50 Z50
F100
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Programming Manual, 02/2011, 6FC5398-2BP40-1BA0
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