Telegram Selection; Measurement Results - Siemens SINUMERIK 840D sl Function Manual

8.4.2

Telegram selection

Telegram selection for the axial measurement with MEAC
By default, the axial measurement is implemented with PROFIBUS telegram 391. PROFIBUS
telegram 395 is used for measuring with several measured values per trigger event and the
position control cycle.
The telegram selection is made from the STEP 7 HW Config, in the "DP Slave Properties" >
"Configuration" dialog.
The following settings are also required:
● Drive parameters:
CU: p0922 = 395; setting for the telegram selection
CU: p0684 = 16; setting of the measuring procedure
CU: p0680; configuration of the central probe terminal
● PROFIBUS connection:
MD13211 $MN_MEAS_CENTRAL_SOURCE = 2 (telegram integration without handshake)
8.4.3

Measurement results

Read measurement results of MEASA, MEAWA
The results of the measurement commands are stored in system data of the NCK and can be
read via system variables in the part program.
● System variable $AC_MEA[No]
Query measurement job status signal.
[No] stands for probe (1 or 2)
The variable is deleted at the beginning of a measurement. The variable is set as soon as
the probe fulfills the activation criterion (rising or falling edge). Execution of the
measurement job can thus be checked in the part program.
● System variable $AA_MM1[axis] to $AA_MM4[axis]
Access to the measured value of the trigger signal in the machine coordinate system. Read
in part program and in synchronized actions.
[Axis] stands for the name of the measurement axis (X, Y, ...).
● System variable $AA_MW1[axis] to $AA_MW4[axis]
Access to the measured value of the trigger signal in the workpiece coordinate system.
Read in part program and in synchronized actions.
[Axis] stands for the name of the measurement axis (X, Y, ...).
Two measuring systems
If the measuring job is performed with two measuring systems, a maximum of two trigger events
can be programmed. The measured values of both probes are acquired for each of the two
probes.
One trigger event
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
M5: Measurement
8.4 Axial measurement
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