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Introduction
This document describes features, parameters and setting possibilities of the WB169-430 module, which is used for
remote reading of iPERL series watermeters by Sensus, that are equipped with 430 MHz data transmitter, and
for resending of read data to the superior remote reading system in form of 169 MHz Wireless M-BUS standard
messages.
1.1
Wireless M-BUS Communication Protocol
Wireless M-BUS is the communications protocol described by international standards EN 13757-4 (physical and
link layer) and EN 13757-3 (application layer), which is intended primarily for radio transmission of remote reading
values from consumption meters and sensors. Protocol Wireless M-BUS (hereinafter
”
WMBUS”) is based on a
standard M-BUS definition (uses the same application layer as M-BUS standard), but is adapted for data transfer
via radio signals.
Communications via WMBUS protocol works in Master-Slave mode, where
”
Master” is a collecting data device,
”
Slave“ is a providing data device. Slave device could be integrated or external radio module transmitting data
from the meter/sensor. The communications protocol WMBUS defines several communication modes (simplex or
duplex). If working in simplex mode a
”
Slave” device only transmits messages to
”
Master” that these messages
receives. If working in
”
bidirectional” mode, it is possible to use a back channel from
”
Master” device to
”
Slave”
device for
”
Request” type of messages, that can contain e.g. request for the change of slave’s configuration.
Wireless M-BUS communications protocol partially supports repeating of the messages. If receiving from some
”
Slave” device is not possible because of the low level of radio signal, the messages can be re-transmitted (repeated)
by appointed element of the radio network (repeater or slave with such functionality). Each repeated message is
marked as
”
repeated message” so as not to be repeated again.
As the receiver of the WB169-430 module is used for receiving of watermeter messages, back channel features cannot
be used for this type of device.
1.2
Module usage
The WB169-430 module can be used as a local
communication gateway
for remote reading of Sensus iPERL-series
watermeters. The module receives regular radio messages with readings (
”
Bubble Up” messages) from watermeters
in its radio-reach and stores the readings to its memory. In pre-defined intervals the module broadcasts aggregate
of received data to the superior remote reading system (AMR) in form of Wireless M-Bus radio-messages in 169
MHz frequency band (”INFO” messages).
The WB169-430 module can by used for remote reading
up to 5 iPERL watermeters
placed in its radio-reach
(that is up to hundreds meters). Each watermeter transmits BUP messages with fixed period of 15 seconds. The
module receives data from watermeters in regular ”receiving windows”, that are opened with preset broadcasting
period (e.g. every 120 minutes). Immediately after closing of the receiving window the module broadcasts received
data from all watermeters to the superior system in one Wireless M-Bus message.
Each module has its table of read watermeters, where there are IDs (serial numbers) of up to five meters that should
be read by the module. If there are other watermeters in the reach, their BUP messages are ignored. The module
can re-send original watermeter alarms (Sensus alarm flags) as well as its own alarm messages.
Each INFO-message contains following data for each read watermeter:
- watermeter ID (serial number)
- watermeter counter value (reading)
- watermeter original alarm flag
- watermeter RF signal strength value (RSSI)
More detailed information about the message content and structure can be found in the paragraph i
Besides the watermeter data each message contains identification of the module itself and current statuses of its
parameters (uptime, battery voltage, processor temperature and transmitting power). The messages are broadcasted
either in open mode (without encryption), or encrypted by AES-128 encryption key. The messages are transmitted
on the 169.4 MHz frequency with data rate from 2.4 kbps to 19.2 kbps (according to used frequency channel).
Messages can be received either by WB169-RFE communication gateway (WMBUS Ethernet GateWay produced
by SOFTLINK), or any other
”
Master” device that complies with the Wireless M-BUS EN 13757-3 / EN 13757-4
standard for 169 MHz frequency band.
WB169-430
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