Siemens SINUMERIK 840D sl Programming Manual page 109

Effectiveness
The check structure cannot be used program-wide.
Nesting depth
A nesting depth of up to 16 check structures can be set up on each subprogram level.
Runtime response
In interpreter mode (active as standard), it is possible to shorten program processing times
more effectively by using program branches than can be obtained with check structures.
There is no difference between program branches and check structures in precompiled
cycles.
Current block display for program loops
If only selected blocks are executed within a program loop, the last main run block before the
program loop is shown in the current block display.
So that the processed selected blocks are also visible in the current block display, e.g. for
diagnostic purposes, the decoding single block SBL2 must be activated.
References
Function Manual, Basic Functions, Section: Mode group, channel, program operation, reset
response (K1) > Single block > Decoding single block SBL2 with implicit preprocessing stop
Job Planning
Programming Manual, 03/2013, 6FC5398-2BP40-3BA1
Flexible NC programming
1.12 Check structures
109