Combining Linux and a softPLC in a single system stands to reason: Linux offers many facilities that modern PLCs are expected to support. However, existing Linux-based softPLC implementations so far have always placed the PLC “on top” of the Linux kernel, so its functional reliability depends on the correctness of the kernel. Due to its size, the Linux kernel can not be exhaustively validated or even proven correct. The approach described in this paper puts Linux and a softPLC “side by side” on top of a small microkernel, thus the two subsystems can coexist safely without being forced to depend on each other.