Three kinds cover everything
Whatever the task, an installation is built from three parts: something that measures or switches; something that listens; and something that processes. The variety sits in the sensors — the rest repeats.
Gateways
They receive from the devices and pass on to the server. One gateway at a sensible height covers a site, a village or a district. It connects by cable or over a mobile network.
Controllers
Inputs and outputs in one box: they read sensors and switch loads — a pump, a valve, lighting. Mains powered, so that a command is acted on immediately.
Sensors
They only measure and report. Years on a battery, which is why they go where cable cannot — chambers, tanks, remote points.
What actually gets measured
| Quantity | How it is taken | Typical place |
|---|---|---|
| Liquid level | ultrasonic or submersible probe | well, tank, chamber |
| Level thresholds | float switches | pumping stations |
| Flow | pulse output of a water meter | trunk mains |
| Pressure | 4–20 mA transmitter | pressure lines |
| Temperature and humidity | digital sensor | stores, farms, plant rooms |
| Opening and vibration | contact, accelerometer | cabinets, doors, equipment |
| Current and energy | clamp, pulse output | metering panels |
The outputs are the same handful: close a contactor, open a solenoid valve, confirm a mode. The logic that drives them lives in the server, not in the device — so changing a rule does not mean a trip to the site.
What to watch for when choosing
- Ingress protection. A chamber or an open site needs IP66 at least. An indoor enclosure lasts one season outdoors.
- Power. Battery where there is no mains and readings are infrequent. Mains as soon as something is being controlled.
- Reporting interval. Every device is entitled to a limited share of the air. Reporting more often means shorter packets or shorter range.
- Antenna placement. A metal cabinet is a screen. An external antenna changes range more than any device choice.
Coverage is tested on site before equipment is ordered. Half a day with one device and one gateway saves reworking a whole installation.