A remote terminal unit (RTU) is a hardware device installed at a site that collects data from connected equipment (generators, batteries, inverters, meters, sensors) and transmits it to a central monitoring platform, while also relaying commands back to the equipment.
An RTU sits at the physical edge of the network. It reads signals from field devices using industrial communication protocols, packages that data, and sends it over cellular, satellite, or other connectivity to the software platform where it’s analyzed and displayed. When an operator issues a remote command, the RTU is what carries it back down to the equipment and executes it.
What an RTU Does: Core Functions
- Data acquisition: Reads analog and digital signals from connected sensors and equipment (voltage, load, fuel level, temperature, and more).
- Protocol translation: Communicates with equipment using industrial protocols such as Modbus, SNMP, BACnet, and CANbus, regardless of the manufacturer.
- Data transmission: Sends collected data to the central platform over available connectivity (2G/3G/4G, satellite, or other links), even at remote or low-connectivity sites.
- Command execution: Carries remote control instructions from the platform back to the physical equipment, enabling actions like generator start/stop or configuration changes without a site visit.
- Local intelligence: Some RTUs perform basic logic locally (edge computing), so critical actions like a safety shutdown can happen even if the connection to the central platform is temporarily lost.
RTU vs. PLC vs. Sensor: What’s the Difference?
| Device | Primary Role | Typical Use |
|---|---|---|
| RTU | Collects data and relays commands between field equipment and a remote platform | Distributed, remote sites needing centralized monitoring/control |
| PLC (Programmable Logic Controller) | Executes local control logic for an industrial process | Single-site automation with less need for remote connectivity |
| Sensor | Measures a single physical value (temperature, voltage, level) | Feeds raw data into an RTU or PLC for processing |
RTUs and PLCs are sometimes used together, with the RTU handling communication to the central platform while a PLC manages fast local control loops.
Why Hardware-Agnostic RTUs Matter
Most distributed fleets run equipment from multiple manufacturers, accumulated over years of purchasing decisions. An RTU built to work with only one brand forces a choice: replace working equipment, or leave part of the fleet unmonitored.
Galooli’s Ultragate gateway supports hundreds of communication protocols, connecting to generators, batteries, inverters, and meters from any manufacturer without requiring equipment replacement, so operators can bring an entire mixed-brand fleet onto a single monitoring and control platform.
Connect With Us
operational cost savings & efficiency?
