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MBUS User Manual (ver 2.01)
MBUS USER MANUAL
1 Introduction
1.1 Quick Start
The Module has a UART interface that is used for both Wireless M-Bus packet data and module configuration. Use
the UART format with settings (19200, 8, 1, N, no flow control).
How do I configure the M-Bus mode, RF channel or any other parameter?
To change configurable parameters:
1. Send one byte to the module with the value 0x00 or assert the CONFIG-pin. This will take the module into
configuration mode. More about configuration mode is found in chapter 2.1
2. Use special commands to access the configuration registers and test modes. All the commands for the
configuration are found in chapter 2.2
3.
Exit from configuration mode by sending the ‘X’ command.
4. Start using the module as normal in packet mode. In some cases you need to reset the module for the changes
to take effect. Details about sending and receiving packet data is found in chapter 2.3.
How do I transmit data?
Send your data to the RXD pin on the module.The first byte of the message must contain the message length sent
over UART. The maximum lengthbyte is 0xF6 since link layer header is added automatically. The module will
transmit the data when the whole packet is received. See page 11 for details about the frame format for
transmitting data. Details about sending and receiving packet data is found in chapter 2.3.
How do I receive data?
Any received RF data packet with correct Wireless M-Bus format and check sums will be output on the TXD pin.
Optionally the meter address (first M-Bus block) is added to the data string. The RSSI value (received signal
strength) can optionally be appended to the message. Also CRC and start/stop bytes can be added. See page 11
for details about the frame format for receiving data. Details about sending and receiving packet data is found in
chapter 2.3.
What about the antenna?
In most cases a simple quarter wavelength wire or a PCB track will do. Connect a piece of wire to the RF pin with
length corresponding to the quarter of a wavelength. For space limited products, contact Radiocrafts and we will
recommend the best antenna solution for your application.
Radiocrafts also offer an Application Note on tuning a 169 MHz antenna in AN025, found here:
https://radiocrafts.com/resources/application-notes/