What held up — PLC, SCADA and telemetry since 2014

Since 2014 Logic Control & Telemetry has commissioned PLC and SCADA work on factories, water works and power-related sites across South Africa. The pattern is consistent: stabilise control first, then add telemetry where assets are spread out, then fix reporting when operators stop trusting the numbers.

What held up

Deterministic PLC logic, conservative alarm design, and SCADA screens operators actually use during a fault. MQTT and OPC-UA only help when buffering and store-and-forward are designed for link loss — the same lesson as on pump-station telemetry. Month-end packs still get built in Excel when the tags and the laboratory results never land in one workflow; that is a reporting problem before it is a historian problem.

What we would not repeat

• Telemetry before the PLC program and alarms are stable
• Sizing a historian from a vendor tag tier instead of the tags that matter for investigations and reports
• A “connected plant” slide where the IO list and the P&ID are still open

If that sounds familiar, start with one site or one report pack — not a platform swap.

Where the work still sits

• Industrial automation and control — PLC, SCADA, panels
• Telemetry — OPC-UA, MQTT, Modbus and DNP3 where the installed base uses them
• Automated reporting and dashboards from the data you already have
• A historian when SCADA retention, query speed or tag licensing is the bottleneck — TDengine Historian on a first install, a replacement, or beside the historian you already run