Siemens SINUMERIK 840D sl Programming Manual page 797

Note
Channel-specific machine data can be used to control counter activation, counter reset
timing and the counting algorithm.
Note
Workpiece counting with user-defined M command
Machine data can be set so that the count pulses for the various workpiece counters are
triggered using user-defined M commands rather than the end of the program (M2/M30).
References
For further information about the "Workpiece counter" function see:
● Function Manual, Basic Functions; BAG, Channel, Program Operation, Reset Response
Job Planning
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
(K1), Chapter: Workpiece counter
Additional functions
14.8 Program runtime/part counter
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