Decreased logging interval?

[eotwash]

Hi!

Are there any ways to decrease the data logging interval below 1 minute?

We run a series of physics experiments that are sensitive to wind gusts at all timescales, even over periods as shorter than 10s. We have a Davis Vantage Vue running Cumulus that we're very happy with, but would like to speed up the readout further. The connection happily ticks along at a reading every 2-3s. We'd be very happy to run in a debug mode where we can write every reading from the Davis to disk. Are there any options in Cumulus (or elsewhere, including commercially) that might work?

Thank you!

[steve]

Not in Cumulus, no. The logging mechanism uses a timer with a resolution of 1 minute. There is no debugging mode which logs every reading. You could set the realtime interval to 2 or 3 seconds to get an approximation to what you want. You would have to devise some way of storing the file before it got overwritten.

It wouldn't be difficult for you write your own code if all it needed to do was continuously write the wind speed to disk. The Davis DLL has its flaws, but makes writing software for the Davis much easier, and would be fine for what you want: http://www.davisnet.com/support/weather ... dllsdk.asp

Commercial alternatives exist; you need to ask elsewhere about the facilities provided by those, for obvious reasons.

[gemini06720]

You did not specify which interface (WeatherLink datalogger) is being used between the Vantage Vue console and Cumulus.

A while back, I bought (from someone in the USA) a home-made interface for the Vantage weather stations - it does not have any onboard memory.

Normally, the interface would be used with the Davis Vantage DLL.

The interface can also directly access the internal memory of the Vantage Pro2/Vue console - without the limitations of the Davis Vantage DLL (I think). With a program written to take advantage of that direct access to the memory, wind gusts could be recorded almost instantly.

[eotwash]

Thanks for the replies! We hadn't known about the Davis DLL.

We use a USB/FTDI cable that we cobbled together in the lab to make the link between a computer and the Vantage Vue, so we probably have direct access to the Vue's memory. Is there an API/list of calls and registers that we can reference? Will the Davis DLL suffice?

Thank you!

Edit: just found this thread, where it does look like the Davis DLL will work through a home-made serial interface?

[steve]

My understanding of the 'home made' interfaces is that they open up the serial interface of the station in exactly the same way as the official adapters. So you can either drive them directly using the standard VP2 serial protocol (the spec is available on the Davis site) or use the DLL; the end result is the same.

[eotwash]

Awesome. Thank you!