Hi stu,
The station driver outputs two values to WeatherCat - the first is a running total of all the rain seen by your station since it was powered up and the other is the current rain rate per hour. The total rain will start at 0 when the console is first powered up and increment over time to 9999. When it gets there it'll reset to 0 (this is Precipitation Total in the Live Data view).
From the total rain all other rain values are calculated - for example if at the start of the day the total rain was 100mm and at the end of the day the total rain is 110mm, then the daily rain is 10mm.
I've uploaded a test build which will dump the raw rain reading it's seeing to the console log:
http://resources.trixology.com/downloads/WeatherCat113B114.zipI would suggest first powering down your console and remove the batteries, then remove the batteries from the external thermo/hygro unit and unplug the rain bucket cable, check the connector is clean and the cable is undamaged, then plug it back in. Put the batteries back in the thermo/hygro unit and the console and make sure all the sensors are being received correctly by the console.
Download the test build as above and get it running. With WeatherCat running, set it's sampling rate to 1 minute (Preferences->Misc 2). Put some water into the rain bucket so it tips two or three times, then wait a minute or two and check WeatherCat's daily rain gauge and rain rate. If they are reading, then all is good.
If they are showing 0, go to Applications->Utilities->Console.app, select 'All Messages' and look for a message from WeatherCat that looks something like:
11/01/2013 16:58:51.704 WeatherCat[47027]: WH1080 rain: 491.4
This is the raw rain as received from your station - it's output about once every 30 seconds - does it look sensible and consistent?