Siemens alarm 14012: Channel %1 block %2 maximum subroutine level exceeded

What it means

Subroutine nesting grew beyond the maximum permitted call depth, typically through recursion or accidental repeated calls. Each call consumes one return level; exceeding the configured stack depth forces an abort. Trace the call hierarchy for recursion or missing returns.

Likely causes

• Subroutine calling itself directly or indirectly
• M-function-triggered cycle calling back into the triggering program
• Deep library calls stacked on an already deep call chain