Program Jumps; Jump Back To Start Of Program - Siemens SINUMERIK 828D Function Manual

K1: Mode group, channel, program operation, reset response
9.9 Program operation mode
9.9.10

Program jumps

9.9.10.1

Jump back to start of program

Function
With the function "Jump back to start of the program" the control jumps back from a part program to the beginning
of the program. The program is then processed again.
As compared to the function "Program jumps to jump marks", with which a repeated processing of the program
can also be implemented, the function "Jump back to the start of the program" offers the following advantages:
• The programming of a jump mark at the start of the program is not necessary.
• The program restart can be controlled through the NC/PLC interface signal:
DB21, ... DBX384.0 (control program branching)
• 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 661] ")
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 Value Description
8 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".
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Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Basic Functions