Hi all, UK newbie here!
I've been reading up on Davis gear for some time (including many threads here - very helpful they are too) and intend to get a VP2 with some add-ons this month.
One of the key decisions I have to make is the subject of this thread - which datalogger. I just thought I'd mention that although the 6510USB is definitely the least expensive one to buy, the IP 6555 can do everything the 6510USB can do and more, using the Weatherlink software provided i.e. it will upload continuously to the Weatherlink website and interface with a PC as well, via your local network if you use Weatherlink software. Weatherlink website apparently provides additional archival backup too, storing four times the amount of data that the datalogger can store and thus providing additional backup should the PC be offline e.g. while away from home. I'm not sure that all the above has come across in the thread so far, so I need to check that I've got it right (which is far from certain!).
The downside (apart from cost) is that, according to
John Dann's site:
third-party software must explicitly support the 6555 logger for full and robust logger operation - compatibility with the 6510 series of Weatherlink loggers alone is insufficient. The VirtualVP utility (v1.2.1 and later) is now compatible with the 6555 logger and should provide a workaround for interfacing the 6555 logger to otherwise incompatible software programs)
... and there is a possible issue with VirtualVP mentioned on that webpage.
But for anyone who doesn't want to have a PC running 24/7 and who doesn't mind the extra cost, and using Weatherlink software or doing the workaround, the IP 6555 logger is well worth considering as it can do more than 6510.
Davis do really need to do some hardware updating here, though, from what I've read - such tiny '20th century' memory chips etc.- and the additional temperature unit limitation (integer data only) should have been addressed too (I might have bought one otherwise). Oh well.
I hope someone will put me right if any of the above is wrong, and with whatever I've missed, as decision time approaches!