Open-Source Containerized IEC 61499 with TSN for Deterministic Field-Level Industrial Communication

Abstract

Containerized virtual programmable logic controllers (vPLCs) promise flexibility and portability over hardware PLCs. However, recent work reveals that proprietary vPLC firmware introduces mean communication latencies of 50 ms due to IP stack polling - a vPLC implementation problem, not an inherent container limitation. This paper demonstrates that the right open-source architecture eliminates this penalty entirely. Two instances of the 4diac FORTE IEC 61499 runtime are deployed as Docker containers with -–network host mode on a PREEMPT_RT Linux host, sharing the host IP stack directly. A Planet TSN-5225-4T switch provides IEEE 802.1AS clock synchronization and 802.1Q priority-based Quality of Service (QoS). Field-level Modbus TCP round-trip time (RTT) is measured with an Acromag physical I/O module including discrete digital and 4-20 mA analogue inputs across four conditions isolating the effects of network load and Time Sensitive Networking (TSN) QoS independently. FORTE achieves a mean RTT of 1.91 ms with $250 \mu ~\mathrm{s}$ jitter - below the real hardware PLC reference of 3.3 ms reported in comparable work. Under 942 Mbps background load, TSN QoS reduces worst-case latency from $6.09 m s$ to 5.47 $m s$, restoring worst-case latency to exactly the no-load baseline. IEEE 802.1AS synchronization achieves a system clock offset of 28-58 ns. The architecture implements the synchronization and basic latency management layers of the TSN toolset; 802.1Qbv gate scheduling is the primary planned extension.