Rain rate discrepancy

[Ned]

I don't run my PC overnight so every morning I download the station data, first to Cumulus 1, then swap to MX for the rest of the day, They run in different folders so their data is saved separately. The main reason for this is to retain the capacity to access the Select-a-graph feature that C1 has and MX apparently does not.

When there has been overnight rain MX shows a large discrepancy in the maximum rain rate between the charts and other places where it is displayed. For instance the rainfall chart today shows a maximum rate of 21.5mm/hr while the dashboard, gauges and Today and yesterday record 46.8mm/hr for the same time. Cumulus 1 recorded 21.5 everywhere and agrees with MX charts.

If rainfall occurs while MX is running and exceeds the rate recorded overnight, the charts and elsewhere then fall into agreement.

[mcrossley]

Next time you start MX, please run it with the -debug command line parameter, then zip up and attach the MXdiags log file.

[Ned]

Thanks, I'll do that, but the next rain is now forecast not to arrive until the middle of next week

[mcrossley]

That's OK, no rain = no issue

[Ned]

Computer motherboard meltdown caused a long delay in getting back up and running during the latest Covid lockdown, but MX is now running again on a new PC.

I've now worked out what is happening, and the discrepancy in rainfall rate is because I applied a calibration multiplier of 0.46 to rainfall, as I increased the collection area of the rain gauge to record smaller increments of precipitation.

It seems MX does not apply the multiplier to rain rate when processing the logger data on starting up, except for the chart which shows the corrected rate.
The amount of rain is still recorded correctly, happy to say.

[mcrossley]

I've checked the code and the rain multiplier is being applied to the rain rate on historic records.
Can you give examples of where the rain rate differs in the log file from the graph?

[Ned]

Today the data log reported 1.7mm/hr (before MX started) and this was the only bucket tip for the day, and the chart agrees with that.
However the dashboard, the rain rate gauge and theToday/Yesterday page all show a maximum rate of 3.6mm/hr, at the time of the single tip.
This behaviour is consistent with previous instances (see my first post, where the maximum 48.6mm/hr, when multiplied by 0.46 gives the corrected rate of 21.5)

[mcrossley]

OK, found the issue, it was hidden in the function that calculates the trend values. Fixed for the next release.

[Ned]

Cheers Mark