Simple M-Bus to 3.3V UART level converter for 1..3 M-Bus slave devices. Board is designed to fit into off-the-shelve Kradex Z105 DIN enclosure. The board has an on-board 5V to 34V boost converter. UART input has an optional low voltage drop diode for the ESP8266 microcontrollers that do not boot when the TX line is pulled down.

Features

• M-Bus voltage: 34 V
• M-Bus slaves: 1..3
• UART level: 3.3 V
• UART connector: 3.5mm screw terminal
• Supply voltage: 5 VDC
• Fuse: 500mA @ 6V
• Short circuit protection: none
• Single layer PCB
• Dimensions: 86x14mm
• Board fits into Kradex Z105 DIN enclosure

Resources

• Design files on GitHub
• Original schematic by Tomas Menzl
• wmbusmeters – Analyze wmbus or mbus telegrams using wmbusmeters
• libmbus: M-bus Library from Raditex Control
• M-Bus discussion on Openenergymonitor.org
• M-Bus to MQTT Logger for ESP8266

Buy

• Bare PCB: 3€ 
  
  
  
• Pre-assembled: 25€
  
  
  
• Pre-assembled with terminals: 30€
  
  
  
• Pre-assembled with terminals and DIN enclosure: 35€