Communication with M-Bus
A43/A44 196 2CMC48001M0201
User Manual Revision: C
10.2.3.1 Selection and secondary addressing
It is possible to communicate with the meter using secondary addressing. The
secondary addressing takes place with the help of a selection:
1. Generation means the same thing as version.
The master sends a SND_UD with the control information 52h to the address 253
(FDh) and fills the specific meter secondary address fields (identification number,
manufacturer, version and medium) with the values of the meter that is to be ad-
dressed. The address (FDh) and the control information (52h) is the indication for
the meter to compare the following secondary address with its own, and to change
into the selected state should it match. In this case the meter answers the selection
with an acknowledgement (E5h), otherwise it does not reply. Selected state means
that the meter can be addressed with the bus address 253 (FDh).
During selection individual positions of the secondary addresses can be occupied
by wildcards. Such a wildcard means that this position will not be taken into ac-
count during selection. In the identification number each individual digit can be
wild-carded by a wildcard nibble Fh while the fields for manufacturer, version and
medium can be wild -carded by a wildcard byte FFh. The meter will remain
selected until it receives a selection command with non-matching secondary ad-
dresses, a selection command with CI=56h, or a SND_NKE to address 253.
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