Hello Paul,
Thank you for responding. Not possible to run the cable between the buildings it would be much more preferable to run the emonpi/base OOB implementation as a starting point. Each can simply connect to the LAN via built in wifi and collect and post data . Really looks like a great platform. I found some info on the emonhub page around interfacers but there are none for Modbus RTU and none I can find for my Autometers DDSD285 device. IT seems that minimalmodbus library might help.
I found this article Read the SDM220 modbus with the minimalmodbus python module - #3 by Joaquin_Lopez but was a little confused by it. The ideal would be have a ‘standard’ interfacer for emonhub which would read the various registers in the meter and post these to emoncms locally and send the data to our hosted emoncms. Each meter point would be a node. We have a main one we plan to monitor the total grid feed statistics and then the others would be on the remote units in the other buildings. We can then use this data for internal cost centre etc.
I have uploaded the latest protocol guide from the supplier.
Autometers Modbus Protocol v6_3_23.pdf (851.4 KB)
I hope this makes sense. Currently waiting for the USB to 485 adaptor to arrive. https://www.amazon.co.uk/gp/product/B01N3LM0PU/ref=ppx_yo_dt_b_asin_title_o00__o00_s00?ie=UTF8&psc=1
Hopefully this should connect directly to the meter using a piece of CAT5e cable. Connections are simple 23 - TX Plus and 24 - TX Minus can’t find a ground so I guess just 2 wire connection.
Any help appreciated and thank you again for responding. I can’t believe that other people would not want this type of sensor data. We can monitor a lot of parameters from this meter it seems.
Another thought line was if we only needed a low power device at each meter station that could run python or other libraries to retrieve the data using mimimalmodbus periodically and simpy post that data to our central emoncms platform using curl or other method.
We would only need a Pi Zero W or something similar running a very basic setup.
Cheers
Tony