Sandaysoft

Note that there are also known issues with using Virtual VP with Cumulus (i.e. with the Davis DLL which Cumulus uses) which Steve Hatchett has been unable to fix, possibly because he was unable to get any help from Davis.

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Steve
Sanday Weather
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Indeed! Over the past weeks, on both my Windows 7 64-bit computers, Cumulus has 'frozen' without producing any error, more so if Cumulus was using one of the serial ports rather than one of the TCP/IP ports.

I think that particular problem occurs when Cumulus calls the DLL to read some data, the DLL calls VVP, and nothing ever comes back, so the Cumulus data reading thread is stuck inside the DLL. Other problems include invalid logger entries being returned, missing logger entries, and no logger data being returned at all (the latter because of a problem where VVP can't read the EEPROM data from the station).

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Steve
Sanday Weather
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As I see this, the protocol to the data logger is published (and the same protocol works direct to the station), but all the client software seems to use the Davis DLL to proxy this protocol?

So two options:

1. Clients connect direct to the data logger - but then no shared connections.
2. Someone writes a 'server' DLL that connects to the Davis and accepts multiple client connections

Hmm, option 2 sounds very much like what we do with telescope mount drivers, where there are multiple clients an a single (usually serial) connection to the telescope controller. The server shares the connections, arbitrates between them, caches responses from the station (so rapid fire queries from clients do not queue on serial responses from the station). The 'scope community has templates for DLLs that implement all of that.

Now if I had a Davis I might have a bash at implementing that...

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Mark
Wilmslow Astro Weather

Cumulus (1) and VWS use the DLL, WD and WL (and Cumulus 2) don't.


What you've described is basically what VVP does. It also caches logger data.

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Steve
Sanday Weather
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