Cynics Soapbox

Random thoughts...

Modbus: 2 Readers, 1 Producer

Modbus: 2 Readers, 1 Producer

Our Solax inverter talks to the power meter via 2-wire modbus. It works well but the inverter really does want a constant stream of information so the requests flow at a high rate. We want to monitor our consumption of electricity, which means we want to look at data from the power meter at the same time as the inverter. This isn't how the Modbus protocol works though. Only one Reader (not the term used in the spec but I'm...

Shapefiles

I recently had a request for a shapefile containing geographic informaton for some of the stations listed on Variable Pitch. I’d been meaning to create a simple export facility for a while, but had never really looked at shapefiles in any detail before. As it took me a few attempts to get them working correctly, the following may help others! I’m using the pyshp python module. import shapefile Essentially I’m creating a shapefile with a list of...

QGIS on Ubuntu 13.10

I’ve been asked about producing shapefiles from the geo data on Variable Pitch. This seems like a good idea, but having no experience with such files I thought maybe I should have an app to test them with. I was pointed at QGis but it needed to be added to the sources list for Ubuntu 13.10. This is how I did it. I created a file /etc/apt/sources.list.d/qgis.list with the contents deb http:...

Consistency?

Ofgem produce a lot of reports. They store a lot of data but when reviewing it I’m constantly astonished at how poor the consistency of that data is. Today I have been looking at a PDF they have available which contains a large number of addresses with countries. This should be such basic data they can’t get them wrong? So why does it list several occurrences of ‘United Kingdon’ and one instance of ‘England’? Is ‘Ireland’ the same...