If you have ever opened Wireshark on a network with Siemens PLCs, you have seen S7comm. It is the language Siemens controllers use to talk to TIA Portal, to WinCC, to SCADA front-ends, and to each other. The protocol has been around since 1994 and it is still the default way to move data in and out of… Read More »
Industrial control systems run the infrastructure that keeps modern life working — electricity, clean water, fuel, food production, and manufacturing. These systems were built for reliability, not for cybersecurity. Most of them use protocols with no authentication, run on operating systems that stopped receiving patches years ago, and sit on networks that were never meant to face external… Read More »
A complete reference for substation engineers comparing the IEC 61850 process bus and station bus — what each bus does, protocols used, hardware requirements, time synchronization needs, redundancy strategies, bandwidth, topology, and procurement considerations Quick Comparison Table Aspect Process Bus Station Bus Purpose Real-time measurement + trip SCADA, configuration, supervisory Replaces Analog CT/VT wiring + binary trips Conventional… Read More »
PROFINET defines three Conformance Classes — CC-A, CC-B, and CC-C — that determine what a device can do. CC-A handles basic real-time communication. CC-B adds network diagnostics and topology discovery. CC-C adds Isochronous Real-Time (IRT) — the hardware-scheduled, sub-microsecond-jitter communication required for motion control, synchronized drives, and time-critical process control. CC-C cannot be implemented with standard Ethernet hardware.… Read More »
Digital substations require time synchronization accurate to better than 1 microsecond. Sampled Values, GOOSE, sequence-of-events recording, traveling-wave fault location, and synchrophasor measurements all rely on precise time across the entire substation network. Standard IEEE 1588v2 (PTP) is powerful but too flexible — it has dozens of options and many possible configurations. To get interoperable, reliable, sub-microsecond timing in… Read More »
A complete reference for substation engineers covering Merging Units — IEC 61869-9 specification, processing delay limits, sample rates, variant codes, SmpSynch values, conformance classes, holdover mode, PTP/1PPS synchronization, procurement template, and field troubleshooting Quick Reference Item Value What it does Digitizes CT/VT signals and publishes Sampled Values on the process bus Standard IEC 61869-9:2016 (replaces 9-2LE guideline) Transport… Read More »
HSR operates entirely at Layer 2. It doesn’t add a new protocol on top of Ethernet — it inserts a six-byte tag into every frame before it enters the ring. That tag is how nodes identify duplicates, track which path a frame took, and know when to remove a frame from the ring. Understanding the tag structure is… Read More »
very DANH on an HSR ring operates in one of six defined modes. They control how the node handles frame forwarding, tagging, and traffic removal. One is mandatory. The rest are optional. If you’re commissioning, testing, or troubleshooting an HSR network, knowing what each mode does — and what it breaks when misapplied — matters. The Short Version… Read More »
Zero-recovery-time redundancy is one thing. Getting your clocks right across that redundant network is another. In substation automation and industrial control, time synchronization isn’t optional — protection functions, event logging, and sampled value streams all depend on it. This article explains how PTP works specifically in PRP and HSR environments, what the standard requires, and where the practical… Read More »
HSR gives you zero recovery time. That part is guaranteed by the protocol. What’s not guaranteed — and what the standard deliberately leaves to implementation — is how much latency each node adds to the ring. That accumulates. Get the ring sizing wrong and you can end up with end-to-end delays that cause problems for time-sensitive applications, even… Read More »