Weather instruments - barometric pressure: incorrect and non-persistent display

  1. Barometric pressure reading in weather instruments on iPhone is incorrect by 3 decimal places.
    Data reading at 7:19:50 5400msecs shows meteorological composite barometric pressure reading is1.0203. Transducer measurement is 102030.

Weather instrument displays pressure reading as 1.0. Correct display is 1020.3

Displayed reading is correct with CE on windows.

  1. Displayed reading of barometric pressure reading disappears after 2 seconds. Instrument displays dashes until barometric pressure device sends another reading.

This particular barometric pressure device sends a reading on the NEMA network approximately every 20 seconds.

Data seen at 7:20:02 400msec shows that the meteorological composite barometric pressure reading is blank, The transducer reading of 102030 persists.

This problem is also seen with CE on windows platform.

FWIW, the barometric pressure display persists as expected when it is viewed on MFD screens from another manufacturer.

Coastal Explorer is getting the barometric pressure from the MDA sentence as the way the XDR sentence was defined makes it essentially proprietary. The current release has a bug where the “bars” value of the MDA sentence is being misinterpreted as “millibars” and we’ve fixed that for the next update.

However, that won’t fix the flashing in this case… The MDA sentence provides barometric pressure, air and water temperature, relative and absolute humidity, dew point, and wind direction and speed. It appears from your screen shots that the device is sending a sentence containing only the barometric pressure and then another sentence containing only the water temperature. Not providing a value in a sentence means that value is “not available” so Coastal Explorer is removing it from the display. (I can’t see all of the sentences you are receiving, but I imagine the water temperature is available in another one or it would be flashing as well.)

We will probably add limited support for a few “well known” uses of the XDR sentence and that would fix this case of the flashing, but I can’t promise anything quite yet…

Thanks for looking at this. The water temp data is from another sensor and is likely updated frequently. I’ll check on that.

I am not a meteorologist, but it is my understanding that an important weather monitor is change in barometric pressure over time.

Rapidly falling pressure of 1 mBar/hr or more suggests potential for severe weather and need to check weather reports, weather radar and possibly head for shelter. Less rapid change, steady, or increasing pressure are also useful weather indicators.

Perhaps future CE might log a time stamped atmospheric pressure reading every 10 minutes or so for the previous 1 to 10 days. Recent data can be viewed in a CE browser table or graph, and used to generate weather alerts. Export of the longer term logged values for review and use outside CE would be nice.

When the atmospheric pressure value in the MDA sentence is empty the display of current pressure might use the most recently logged value if it is less than 20 minutes old (assuming values are logged more frequently.)