Gateways next to PLCs and machines publish telemetry, alarms, counts and quality results; MES, SCADA dashboards, OEE analytics and maintenance tools subscribe. MQTT keeps the shop floor decoupled from the applications that consume its data — the backbone of a smart factory.
No card required
You build the applications, ConnectMQ moves the data. Gateways next to PLCs and machines publish once; MES, SCADA screens, OEE analytics and maintenance tools each subscribe to the topics they need — add a new consumer without touching the shop floor.
plant/dallas/line-1/press-04/telemetry
plant/dallas/line-1/press-04/alarms
plant/dallas/line-1/press-04/status (retained)Machines publish state, cycle counts and scrap; your OEE dashboard calculates availability, performance and quality per line in real time.
Vibration, temperature and oil readings stream to your maintenance models; rules open a work order before a machine trips.
Energy meters publish next to production counts, so you can follow kWh per part, line and shift.
Test stations publish results with the serial number and line, and your MES links every part to its process data.
Alarms reach andon lights, supervisor phones and the MES at once — one message, every subscriber.
Every plant publishes into the same ISA-95 topic tree, so headquarters compares sites with one wildcard subscription.
Line 2 dashboard subscribes to acme/dallas/press-shop/line-2/#
matched by the subscription
Name topics after the ISA-95 hierarchy — enterprise, site, area, line, machine — and every application finds data by where it comes from. One wildcard subscription gives a line dashboard everything it needs, and ConnectMQ’s ISA-95 workspace shows the same tree live.
A typical plant setup with MQTT: an edge gateway next to the PLCs publishes machine data, the maintenance system in the office subscribes, and the andon light on the line listens to the same broker. Shop floor and office both connect out to ConnectMQ over TLS.
14:02 Edge gateway on line 2
Reads the PLC every second and publishes an alarm when the hydraulic oil passes 75 °C.
acme/dallas/press-shop/line-2/press-08/alarms → {"code":"HYD-TEMP","value":78}14:02 Maintenance system
Subscribed to the line’s alarms through ConnectMQ: it opens work order #4812 and switches the line’s andon light to red.
acme/dallas/press-shop/line-2/andon/set → {"color":"red"}14:02 Andon light on line 2
Turns red and confirms, so the operator sees the alarm right at the machine.
acme/dallas/press-shop/line-2/andon/state → red14:03 Technician’s phone
Gets the work order with the alarm values — before the press trips on overtemperature.
If the gateway loses its connection, its Last Will acme/dallas/press-shop/line-2/gateway/status → offline tells every subscriber that the line has gone silent — not that everything is fine.
Hubs, sensors and Home Assistant setups
Vehicle tracking, telematics and cold chain
Meters, EV chargers, solar and batteries
Smart devices you ship to your own customers
Robot fleets talking to fleet managers and AI pipelines
Power, cooling and rack environment
Streetlights, parking, air and waste sensors
Soil probes, weather stations and irrigation
From first ESP32 to classroom labs
Start on the Free plan with no card. Basic covers up to 100 concurrent connections — enough for the gateways of a pilot line. Move to Scale when the whole plant goes live.
