Wireless Level Monitoring: LoRa, NB-IoT and 4G for Remote Tanks

A level instrument on a tank in the middle of nowhere has one overriding constraint that a wired instrument never faces: energy. Every feature — how often it measures, how far it transmits, how long it lasts — is a trade against a battery. Choosing the radio technology is therefore not a technical trivia question; it is the decision that sets the whole power budget, and getting it wrong means a sensor that is dead in six months instead of six years.

The three radios, and what each is for

LoRa / LoRaWAN. LoRa is a radio modulation technology; LoRaWAN specifies the network protocol and architecture. A LoRaWAN deployment uses a gateway and network server, which can be private or provided as a service. It suits small messages and energy-conscious reporting, with capacity and latency constrained by region, airtime, network load and device class.

NB-IoT. This cellular IoT technology can support low-energy devices through supported network power-saving features. Confirm the operator, band, actual site coverage, SIM service and latency. It is not restricted to readings every few hours; attainable reporting and alarm response depend on the module, coverage, sleep settings and application.

LTE-M and other LTE categories. LTE-M is a low-power cellular IoT option, not simply a high-power broadband radio. Cat-1, Cat-1 bis and other LTE devices have different data and power characteristics. Compare measured wake-up energy, throughput, latency, firmware-update needs and operator support rather than grouping every LTE modem under one power rating.

Technology	Infrastructure to verify	Main energy and response factors
LoRaWAN	Gateway, network server and backhaul, private or public	Airtime, spreading factor, retries, regional rules and device class
NB-IoT	Actual operator and band support at the site	Coverage, registration, repetitions, PSM/eDRX and message interval
LTE-M	Actual operator and module support	Coverage, sleep behaviour, traffic and latency
Other LTE categories	Service plan and site coverage	Module category, connection time and data volume

MV-RD11 Lightweight 80 GHz Radar Level Meter

The power budget is the real spec

Battery life depends on measurement energy, radio wake-up and registration, transmission retries, reporting interval, sleep current and usable battery capacity. Increasing the interval means fewer reports and usually longer life; reducing it usually consumes more energy. Obtain measurements for the actual sensor, coverage and temperature instead of accepting a fixed lifetime claim.

For non-contact radar, which needs a measurement burst that costs real power, the reporting interval is the lever. Many remote designs use a wake-and-measure cycle: the sensor sleeps, wakes on a timer, takes one measurement, transmits, and returns to sleep. The engineering is in making that one wake-up cheap.

MV-RD13S Bracket-Mounted 80 GHz Radar Level Meter

Choosing for the site

Many tanks on one site → assess a private or public LoRaWAN deployment, including gateway coverage, backhaul, network capacity, maintenance and ownership cost.

Scattered remote tanks → compare supported NB-IoT and LTE-M services at the actual sites, using the required reporting interval and battery budget.

Need prompt alarms → establish the complete detection-to-notification delay and availability, including measurement interval, sleep, registration, retries, server and recipient. No radio label guarantees immediate delivery.

The other axis is what happens when a reading is out of range. A remote level system is only as useful as its alarm path: decide whether the device pushes an alert on its own, whether the cloud platform raises it, and who gets it — because a remote tank you cannot alarm on is just a remote tank you still have to drive to.

Questions engineers ask

Q1. How long will the battery really last?

That is a function of the reporting interval, not a fixed number. Get the manufacturer's battery-life curve against interval, and design the interval to the application, not the marketing number.

Q2. Does LoRa need a licence?

Many deployments use licence-exempt spectrum subject to national frequency, power, access and equipment-approval conditions. Check the destination rules and the appropriate LoRaWAN regional parameters. A private gateway does not remove those obligations; a public network may add a service subscription.

Q3. Can I use wireless for a safety function?

Ordinary wireless inventory monitoring must not be credited as an independent safety trip without a specific functional-safety design and validation. Wireless technology is not categorically excluded, but the complete function would need demonstrated latency, availability, failure response, integrity and independence. Keep the routine monitoring radio outside a credited safety function unless the safety assessment establishes otherwise.

Q4. What is the real cost difference?

The radio module is a small part; the cost is in battery replacement visits, gateway ownership and data plans over years. Compare total cost of ownership, not the sensor price.

Related technical guides

Discuss your measurement application with METRAVON