IIoT Connectivity Options: Cellular, Wi-Fi, LoRaWAN, and Wired

Every IIoT project starts with a connectivity question: how does the data get from the sensor to the platform? The answer shapes cost, battery life, and reliability for the life of the deployment.

The Options

• Wired (Ethernet, RS-485, fieldbus): most reliable, needs cabling, best where devices are fixed and power is available. Still the default for control systems.
• Wi-Fi: high bandwidth, cheap infrastructure, but range and interference vary with the factory environment. Fine for mobile HMIs and tablets; weak for dense sensor fields.
• Cellular (4G/5G, LTE-M, NB-IoT): works anywhere with coverage, no site infrastructure, recurring SIM cost. Ideal for remote sites, mobile assets, and fleets. LTE-M and NB-IoT are designed for low-power sensors.
• LoRaWAN: long range (kilometers in open areas), very low power, very low data rate. Best for infrequent, small readings - tank levels, environmental monitoring, asset tracking.
• Proprietary sub-GHz (WirelessHART, ISA100.11a): proven in process plants with mesh reliability and battery operation, at the cost of vendor-specific infrastructure.

Selection Criteria

1. Distance and environment (metal racks, concrete walls, outdoor spans).
2. Data rate and latency the application actually needs.
3. Power source - mains or battery, and how many years between battery changes.
4. Coverage and who owns the infrastructure.
5. Security and spectrum licensing considerations.

A Practical Bias

For fixed plant equipment, wire it when possible. For sensors where wiring is genuinely impractical, prefer standards-based, multi-vendor wireless (LoRaWAN for sparse low-rate, LTE-M for denser or mobile). Avoid single-vendor proprietary links for anything you expect to maintain for a decade.