Correcting erroneous barometric pressure readings from Davis Weather Envoys
The Davis Weather Envoy (model number 06316)is effectively a display-less console for a Davis Vantage Pro-2 weather station. It is a convenient way to connect your Macintosh to your weather station instruments while allowing you to place the display console in some other part of your house.
Unfortunately, there was a production run of the Davis Weather Envoy units which had their internal barometric pressure sensors reading low compared to the console and professional readings. This can be corrected, but requires (for the moment) the use of the Davis WeatherLink software that came with your datalogger. This software is now out of date compared to current Apple software standards. To run it at all you must first change it to run in 32-bit mode only. Selected the WeatherLink application and use the Finder Get Info option to bring up this window:
Now you can launch WeatherLink and make the correction. The simplest thing to do is to add a station as described in the WeatherLink manual:
Then proceed through the Station walk-through until you reach the barometric pressure correction, leaving all other corrections unused.
There are plans to allow WeatherCat to make this correction without the use of Davis WeatherLink software, but this is the only method to make this correction at this time.