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WRMnano User Manual page 3/18
1. General description
WRMnano is a device, w ic translates OMS wireless m-bus messages to wired
m-bus. It receives wireless m-bus messages and saves t em in its internal memory. It
can save data for up to 64 wireless devices. T en it can relay data for any saved
wireless device upon request wit valid wired m-bus telegram (usually REQ_UD2). It
is powered entirely by m-bus, t us assisting easy mounting and best possible
placement.
If more t an 64 wireless m-bus devices must be relayed to wired m-bus, t en
several WRMnano devices s ould be employed, all on t e same m-bus interface. In
t is case user s ould take care to set different Primary addresses bot to WRMnano
devices and integrated meters, if reading is to be made by Primary addresses.
Eac WRMnano as its own Primary address (settable by user) and unique
Secondary address - WRMnano serial number. T ey are used w en programming
WRMnano suc as activating/deleting new meters in its memory, saving AES-128 key
for desired meter and so on.
All wireless messages from different meters are saved in WRMnano internal
memory, based on t eir identification number (ID). T ere are two modes of WRMnano
operation:
o automatic mode – in t is mode automatic activation is implemented. W en
WRMnano receives valid wireless m-bus message, it activates t e ID of t e
device, (if not already activated), saves t e message in its internal memory,
and updates it upon eac reception. It is done until t e maximum 64
devices are activated. T en only messages are updated upon eac new
reception. Eac new device will ave Primary address of 0;
o manual mode – t e IDs of t e wireless m-bus devices t at s ould be read
must be manually activated in t e WRMnano memory. T is way WRMnano
saves only t e messages from t e already activated devices and ignores all
ot er radio messages. T is activation is made t roug m-bus interface and
since its wit manufacturer specific telegrams user s ould use our software
for t is or implemented commands in is own system. M-bus telegrams are
described furt er in t is document.
T e saved telegrams from t e wireless devices can be accessed via standard
readout m-bus command, s ort telegram (REQ_UD2). Activated radio devices wit in
WRMnano memory act as separate logical wired m-bus devices, eac wit its own ID
and primary address. T e ID is t e same as t e one of t e wireless device, and t e
primary address can be set by (and c anged any time) t e master. T e default value
for primary address, as mentioned above, is 0. WRMnano as its own ID and primary
address, and all commands to t e device (activation/deletion of RF device, work mode
selection, setting various options) s ould be send to t is address. By default device is
set wit Primary address 249.
WRMnano also supports mode 5 AES-128 decryption of t e received wireless m-
