Page
13
of
60
©
2019 Radiocrafts AS
MBUS User Manual (ver 2.01)
MBUS USER MANUAL
The module supports the new Extended Link Layer (ELL), its new AES-128-CTR mode of encryption, and the new
compact frame formats, all according to EN13757-4 (2013). The new ELL can be used for all modes.
The MBUS4 supports the mode N (169 MHz) variant of the Wireless M-Bus standard as specified in the EN 13757-
4 (2013). The implementation supports both N1 (unidirectional communication) and N2 (bi-directional
communication). That is, two-way communications with transmission and reception by both Slave and Master is
implemented, including the two-way timing for sleeping Slaves.
The MBUS4 functionality is similar to the MBUS3 functionality, with the addition of the Master supporting 256
meters (Slaves) internally and > 1000 Slaves registered externally (in the host).
As for MBUS3, the MBUS4 Master can be configured to receive all messages, or only installed meters. Messages
to/from installed meters can be encrypted/decrypted.
The MBUS4 receives and decodes mode N with both Frame Format A and B automatically in real-time. The Frame
Format used for transmis
sion of messages is set by the “PREAMBLE_LENGTH” parameter, as described below.
The number of channels in mode N were extended in the 2018 revision of EN13757-4. This revision also added a
new data rate at 6.4 kbps. The channel and data rate settings to support this is shown below.
The MBUS4 support both Application Layer (i.e. Transport Layer) encryption and the new Link Layer Encryption,
using the Extended Link Layer, as specified in EN13757-4 (2013). The module accepts all CI-fields and will
automatically use the correct encryption scheme. Encryption / decryption is enabled in the Flag Register. The
default value of the Flag Register encryption / decryption flags are set using the ENCRYPT_FLAG /
DECRYPT_FLAG configuration parameters as for MBUS3. When ELL is used and encryption is enabled, the
module also automatically adds the correct PayLoad CRC. The PayLoad CRC can therefore be set to 0x00 by the
host in this case.
2.5 MBUS Basic functionality
The module offers a buffered packet radio acting as a Wireless M-Bus modem. The module contains a fully
embedded protocol supporting the following modes:
•
Stationary mode S (S1, S1-m, S2)
•
Frequent transmit mode T (T1 and T2)
•
Frequent receive mode R2
•
C1 mode
•
Narrowband mode N (N1 and N2)
The mode is configurable by the MBUS_MODE parameter.