In addition to the usual supply meters, there are a set of sub-meters in the house to report on particular aspects of resource consumption:<\/p>\n
While it’s perfectly possible to read these meters manually (which is what I have been doing, on the first day of every month) the plan was always to read them automatically and to log the usage on a much more frequent basis. In line with my policy of using non-proprietary standards with good Open Source software support I settled on using the\u00a0Meter-Bus<\/a>\u00a0standard (usually abbreviated to M-Bus, not to be confused with Modbus<\/a>) to do this and hence specified \/ purchased meters with M-Bus interfaces.<\/p>\n (Actually, most of the Electricity meters don’t have M-Bus interfaces since those only seem to be available on the higher-capacity meters – 80A or so – and they attract a very high price premium. For the low-current sub-meters I used small DIN-Rail mounting meters with S0 pulse outputs rather than M-Bus interfaces, on the basis that it was better to have a simple meter than no meter at all.)<\/p>\n I cover a lot of the technical aspects of M-Bus on my\u00a0M-Bus Meter Data Collection<\/a>\u00a0Page so see that for more details. The event that prompted this Post is that I’ve just<\/em> got the water meter data collection working. It took me an embarrassingly long time to spot that the Itron Aquadis water meters were initially supplied with Pulse-Counting Cyble modules rather than M-Bus Cyble modules and once that was corrected it took a while to get the right version of the software needed to configure those. Kudos to the team at MWA Technology<\/a>\u00a0in Birmingham for helping me out (and no thanks to Itron for being thoroughly unhelpful – they only seem to want to deal with their big distributors).<\/p>\n I’ve found the best way to talk to an M-Bus meter from Linux is using the libmbus<\/a> software. Basically this provides two data access mechanisms:<\/p>\n I briefly toyed with the idea of writing a Perl module to map the C API to Perl so I could call it directly from a Perl script and then I wrote a simple C program to grab a limited set of data using the C API. However, in the end, I decided it was better to go down the XML route and to parse the full XML output string to extract the necessary data fields. I’ve written a Perl script which runs continuously (on the Raspberry Pi connected via an RS-232 interface to the M-Bus protocol converter) and extracts the data from all the M-Bus meters every few minutes. It then publishes the readings as messages using MQTT<\/a>\u00a0from where they follow the same route of logging and graphing used for other monitoring (Telegraf -> InfluxDB -> Grafana).<\/p>\n Some observations:<\/p>\n An example of the full XML response from one of the Itron Aquadis water meters with an M-Bus Cyble communications module<\/a> installed is shown below. Only the block highlighted in bold is really of interest (and actually it’s only the Value of 20312 which changes – that’s the same as displayed on the meter readout).<\/p>\n In addition to the usual supply meters, there are a set of sub-meters in the house to report on particular aspects of resource consumption: Water Meters, to assess how the water usage is broken down (e.g. hot water versus cold … Continue reading \n
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<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\r\n<MBusData>\r\n\r\n <SlaveInformation>\r\n <Id>17003877<\/Id>\r\n <Manufacturer>ACW<\/Manufacturer>\r\n <Version>20<\/Version>\r\n <ProductName>Itron CYBLE M-Bus 1.4<\/ProductName>\r\n <Medium>Water<\/Medium>\r\n <AccessNumber>23<\/AccessNumber>\r\n <Status>00<\/Status>\r\n <Signature>0000<\/Signature>\r\n <\/SlaveInformation>\r\n\r\n <DataRecord id=\"0\">\r\n <Function>Instantaneous value<\/Function>\r\n <StorageNumber>0<\/StorageNumber>\r\n <Unit>Fabrication number<\/Unit>\r\n <Value>17003877<\/Value>\r\n <Timestamp>2017-06-30T08:03:19<\/Timestamp>\r\n <\/DataRecord>\r\n\r\n <DataRecord id=\"1\">\r\n <Function>Instantaneous value<\/Function>\r\n <StorageNumber>0<\/StorageNumber>\r\n <Unit>cust. ID<\/Unit>\r\n <Value>0A\u00a0 \u00a0 \u00a0 \u00a0 <\/Value>\r\n <Timestamp>2017-06-30T08:03:19<\/Timestamp>\r\n <\/DataRecord>\r\n\r\n <DataRecord id=\"2\">\r\n <Function>Instantaneous value<\/Function>\r\n <StorageNumber>0<\/StorageNumber>\r\n <Unit>Time Point (time & date)<\/Unit>\r\n <Value>2017-06-30T09:02:00<\/Value>\r\n <Timestamp>2017-06-30T08:03:19<\/Timestamp>\r\n <\/DataRecord>\r\n\r\n <DataRecord id=\"3\">\r\n <Function>Instantaneous value<\/Function>\r\n <StorageNumber>0<\/StorageNumber>\r\n <Unit>bat. time<\/Unit>\r\n <Value>5352<\/Value>\r\n <Timestamp>2017-06-30T08:03:19<\/Timestamp>\r\n <\/DataRecord>\r\n\r\n <DataRecord id=\"4\">\r\n <Function>Instantaneous value<\/Function>\r\n <StorageNumber>0<\/StorageNumber>\r\n <Unit>Volume (m m^3)<\/Unit>\r\n <Value>20312<\/Value>\r\n <Timestamp>2017-06-30T08:03:19<\/Timestamp>\r\n <\/DataRecord><\/strong>\r\n\r\n <DataRecord id=\"5\">\r\n <Function>Instantaneous value<\/Function>\r\n <StorageNumber>0<\/StorageNumber>\r\n <Unit>Volume (m m^3)<\/Unit>\r\n <Value>0<\/Value>\r\n <Timestamp>2017-06-30T08:03:19<\/Timestamp>\r\n <\/DataRecord>\r\n\r\n <DataRecord id=\"6\">\r\n <Function>Instantaneous value<\/Function>\r\n <StorageNumber>1<\/StorageNumber>\r\n <Unit>Volume (m m^3)<\/Unit>\r\n <Value>0<\/Value>\r\n <Timestamp>2017-06-30T08:03:19<\/Timestamp>\r\n <\/DataRecord>\r\n\r\n <DataRecord id=\"7\">\r\n <Function>Manufacturer specific<\/Function>\r\n <Value>00 01 1F<\/Value>\r\n <Timestamp>2017-06-30T08:03:19<\/Timestamp>\r\n <\/DataRecord>\r\n\r\n<\/MBusData><\/pre>\n","protected":false},"excerpt":{"rendered":"