Isolated M-Bus to TTL Signal Converter for Smart Metering
- Client
- Utilities & energy
- Year
- 2024
- Category
- Internet of Things (IoT)
Many meters use M-Bus, while microcontrollers and IoT gateways typically use UART/TTL. NELSco designed an isolated converter with selectable 3.3 V/5 V output; the interface was developed with reference to EN 13757-2/3 and includes circuitry intended to reduce surge, ESD, and reverse-polarity risks.
Galvanic isolation designed around a ≥1.5 kVDC target to reduce ground-loop and interface risks, with an M-Bus physical layer developed with reference to EN 13757-2/3 and selectable 3.3 V/5 V UART/TTL output.
Integrated circuitry intended to reduce surge, ESD, reverse-polarity, and EMI risks, with UART/TTL integration options for common microcontrollers, gateways, cellular modules, and SCADA equipment.
The Challenge
M-Bus carries its own voltage and power levels, so direct MCU connection can create hardware, ground-loop, and data-integrity risks. The design called for an isolated interface suited to the M-Bus physical layer and common gateways in the evaluated configurations.
Our Approach
The board uses galvanic isolation between the M-Bus and TTL sides, designed around a ≥1.5 kVDC isolation target. The interface was developed with reference to EN 13757-2/3, with selectable 3.3 V/5 V UART/TTL levels, 300–9600 bps support, and integrated protection circuitry. System-level withstand and standards conformity require validation of the final assembly.
The Result
The converter provides a UART/TTL interface for ESP32, STM32, LoRa gateways, cellular modules, and SCADA equipment. Compatibility, voltage levels, and communication settings are verified for each target system.
Results
- Smart reading of water, gas, and electricity meters in IoT deployments
- Galvanic isolation intended to reduce risk to downstream electronics
- Provides an isolated interface between legacy M-Bus meters and modern data-acquisition systems
Have a similar project?
Get in touch with NELSco's engineering team to discuss your project requirements.