Attention

IronPLC implements many parts of the IEC 61131-3 standard and is working toward full Structured Text support. Key features still missing include structures and user defined function blocks.

Variables

Vendor extension variables provided by IronPLC. These are implicit global variables injected by the compiler and updated by the VM at runtime.

Variable	Description
__SYSTEM_UP_TIME / __SYSTEM_UP_LTIME	Monotonic uptime since VM start