Max/min readings and data intervals

[Jaymel]

A couple of questions about memory and data points. I download data once a day (to Cumulus and HeavyWeather) from the WS-2350 internal memory.

But HeavyWeather displays max/min data which do not appear in the table if you click on the "Show history" button. This table is apparently generated from the history.dat file. So is this file incomplete (in that it does not contain any max/min data) or are the max/min data in the file and not shown in the table, but are extracted from it to show in the main HeavyWeather display? This was discussed in another forum some time ago (see http://www.wxforum.net/index.php?PHPSES ... opic=719.0), but not answered clearly. The history.dat file is not readable in a text editor, so it is not possible to see if it contains the max/min data or not (and hex file editors mean nothing to me).

According to the 2350 advertising material "All the weather data from the base receiver station and up to 175 sets of weather history data (with user adjustable measuring intervals) can be recorded and uploaded to your PC.". If that is true, the max/min data should be there somewhere. Steve, do you know if HeavyWeather creates its history.dat file from the same memory as you use to download to Cumulus? If so, would it be possible to modify Cumulus so that it too could read these max/min points?

For my second question, could someone please explain how data point intervals are decided upon. According to the 2350 manual, the measuring interval of the outdoor thermo-hygro sensor is 32 seconds or 128 seconds depending upon windspeed, or 8 secs with wired transmission. For internal temp and pressure, it is 4 times a minute (ie once every 15 seconds). Now how do these appear as one set of weather history data? If the first reading is at time 0, and all the points are read, when would the next "set" of points be read, and so on? And how does this tie in with the "user adjustable measuring intervals"? I have set the HeavyWeather History Period to 30 minutes, and this is what appears in the history.dat table. It appears to be the same thing for Cumulus, as this shows data at the same 30-minute intervals (with its "recent extremes" taken from the same data intervals while it is not connected in real time to the 2350). The HeavyWeather max/min points can be at any time - ie not linked to the 30 minute intervals. How does the Cumulus data logger interval (which I have left at 10 minutes) tie in with the HeavyWeather 30-minute History Period? I assume that the latter overrides the former as all readings in Cumulus appear to be at 30-minute intervals, although I note that Cumulus is updating its readings all the time it is connected to the 2350.

I hope this isn't too confusing; my thanks for any clarification.

[steve]

I don't know anything at all about Heavyweather, and very little about the hardware itself, so I can't answer any of your questions about those, I'm afraid.

Your question about the max/min being missed is, coincidentally, the same as a question asked yesterday about Fine Offset stations. Currently, Cumulus only uses the logged or read data to determine max and min values, it ignores the highs and lows in the station. This is because originally Cumulus was intended to be run 24/7, so the issue didn't arise. This can lead to extremes occasionally being missed when using data from the logger (in particular wind gusts), the likelihood of which increases with your logger interval, if the station doesn't log the extreme in the logger entry, which it appears is true in this case. I hope to do something about this (i.e. use the highs and lows in the station) in Cumulus 2.

I suspect that when you set the Heavyweather logger interval to x minutes, that has the effect of setting the station logger interval to the same value, which is why it affects Cumulus when it's downloading data from the logger. When you set the logger interval in Cumulus, you are setting the interval that it uses while running. When it's downloading data from the logger at start up, it creates one log entry for every entry it finds in the logger.

Steve

[Jaymel]

Your question about the max/min being missed is, coincidentally, the same as a question asked yesterday about Fine Offset stations. Currently, Cumulus only uses the logged or read data to determine max and min values, it ignores the highs and lows in the station. This is because originally Cumulus was intended to be run 24/7, so the issue didn't arise. This can lead to extremes occasionally being missed when using data from the logger (in particular wind gusts), the likelihood of which increases with your logger interval, if the station doesn't log the extreme in the logger entry, which it appears is true in this case. I hope to do something about this (i.e. use the highs and lows in the station) in Cumulus 2.

I had a look at that Fine Offset question. These stations work in strange ways. Getting Cumulus to work with them all must have been fun. Are you going to put yourself through more joy for Cumulus 2?

I suspect that when you set the Heavyweather logger interval to x minutes, that has the effect of setting the station logger interval to the same value, which is why it affects Cumulus when it's downloading data from the logger. When you set the logger interval in Cumulus, you are setting the interval that it uses while running. When it's downloading data from the logger at start up, it creates one log entry for every entry it finds in the logger.

That's what I thought. I will try running Cumulus continuously for a few hours to see what that turns up. Only reason I haven't been running it 24/7 is the electricity bill with the PC on continuously.

I've just remembered a question I wanted to ask. I left Com1 at the default of 9600 bps when changing from USB/serial to serial so that Cumulus would work ok. Has anyone increased this to see what rate the WS-2350 will accept without introducing errors?

Jaymel