Siemens SINUMERIK 840D sl Function Manual page 539

● The timer for the program runtime can be reset to "0" at the restart of the program.
● The timer for workpiece counting can be incremented by "1" at program restart.
Application
The function is used, if the processing of subsequent workpieces is to be done through an
automatic program restart e.g. in case of turning machine with bar loader/-changer.
Activation
The jump back takes place only when the following NC/PLC interface signal is set:
DB21, ... DBX384.0 (control program branching) = 1
If the signal is at "0", then no jump back is exected and the program processing is continued
with the next part program block after the function call.
Parameter assignment
Program runtime
The runtime of the selected NC program is stored in the system variable $AC_CYCLE_TIME.
When starting a new program, the system variable is automatically reset to "0"(see Chapter
" Program runtime (Page 641) ")
Via the following machine data it can be set that the system variable $AC_CYCLE_TIME is
reset to "0" even in case of a program restart through the function "jump back to start of
program":
MD27860 $MC_PROCESSTIMER_MODE (Activation of the program runtime measurement)
Bit
8
Note
In order that the setting of bit 8 can become effective, the measurement of the current program
runtime must be active (MD27860 bit 1 = 1).
Workpiece count
After the part program end (M02 / M30) has been attained, the activated workpiece counters
($AC_TOTAL_PARTS / $AC_ACTUAL_PARTS / $AC_SPECIAL_PARTS) are incremented by
"1" (see Chapter " Workpiece Counter (Page 647) ").
Via the following machine data it can be set that the activated workpiece counter is incremented
even in case of a program restart through the function "jump back to start of program":
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Value Description
0 $AC_CYCLE_TIME is not reset to "0" by the function "jump back to start of program".
1 $AC_CYCLE_TIME is reset to "0" by the function "jump back to start of program".
K1: Mode group, channel, program operation, reset response
9.9 Program operation
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