Siemens SINUMERIK 840D sl Function Manual page 675

Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Note
MEASA and MEAWA can be programmed in the same block.
MEASA cannot be programmed in synchronized actions.
The axes for which MEASA has been programmed are not decelerated until all
programmed trigger events have arrived.
Measurement jobs started from a part program are aborted by RESET or when the
program advances to a new block.
If MEASA/MEAWA are programmed in the same block as MEAS/MEAW, the configuration is
rejected with alarm 21701.
If a geometry axis is used in a measurement, the measured values are only made
available in the workpiece coordinate system if all geometry axes are programmed with
the same measurement job. If a geometry axis is missing from the measurement job, the
measured values are stored only in the machine coordinate system and alarm 21702 is
generated. The same applies to axes involved in a transformation.
If the measurement should begin with the probe edge, but the position of the probe is not
known when the measurement is started, the customer must evaluate this in the part
program. Querying the probe state can generally determine that the next respective
probe edge detected by the hardware (positive or negative) will start the measurement
job.
if $A_PROBE [1] =1 ; probe deflected?
MEAC [X] = (1,1,-1,1) ; starts with the first detected negative edge.
else
MEAC [X] =(1,1,1,-1) ; starts with the first detected positive edge.
endif
The alarms are described in the online help or in:
References:
/DA/ Diagnostics Guide
Measurement (M5)
8.5 Axial measurement (optional)
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