New style passive shield

I see that it boasts a “Universal temperature sensor clamp for up to 20mm diameter sensors”

Couldn’t get a wireless WMR200 sensor in there, then.

Hi guys i have both shields and the plates or plastic and the metal is the mounting arm. The standard shield sensor chamer is 2.6 inches in diameter, the Davis sensor fits it just fine and the pro shield diameter is1.6 inches because it has a black second shield inside the first. So far the pro is doing just fine with the single louvered shield generally running about .5 to .8 higher than the davis fars and that is with no to very low wind, it runs about the same temp when the wind is around 3 mph or higher. They are in the process of restocking their New York store, a government group bought all they had and having to go through customs it takes time.

How did you calibrate/match the sensors themselves? Did you run them all together in the same shield for a period and plot the discrepancies?

I did the poor mans setup had them side by side for temp checks. The standard shield has an sht31 Davis sensor in it and the pro has a sht75 that i put together because of the smaller inner chamber of the pro.

What sensor does the fARS have?

The fars has a sht31, the new one that davis put out a couple years ago. Does real well on temp but the humidity seems to be iffy after exposure to high humidity for long periods of time. The sht75 specs are close to the same but comes mounted on a breakout board with pins to plug into a socket. Makes it small when using the factory filter and not too difficult to mount. Has good response time too.

I see now, the SHT75 is the SHT15 mounted and pinned.

Well sort of it has better specs by a tad and unless you get one on a breakout board and use the factory filter it is rather big as a davis filter. The only problem with the sht1x and 7x series of chips is they are being phased out in favor of the sht3x series of sensors which use the i2c format and the old ones use the sensibus format.

I’m not seeing that difference on the SHT15 and SHT75 data sheets, could you point me to the difference in spec?

As i recall the 75 humidity is 1.8% and the 15 is 2% and from using both sensors the 75 is a little more accurate when the humidity is low by about 2%. The 15 tends to run a couple percent wetter.

Gotcha, I was looking at temps :roll:

SHT15 High-End

SHT75 High-End

Really not much but like i said the low end performance of the 75 is better than the 15 and the response time is a little better too.

It’s apparently the same chip :?

There is a difference in the chips, the 15 is smd style with connection on the side of the housing as well as underneath and the 75 only has the connections on the bottom of the chip so the board it is mounted on is very small and just fits the board. Why the tad better humidity specs is any ones guess, hard to figure .2% difference lol.

I was referring to the silicon itself.

Ok on that i don’t know how you find .2%, maybe they cull the better speced ones, no they have different mounting cases, so who knows lol.

Speaking as someone who has been part of the creation of many semi datasheets, I would say you have a lot of faith in a pretty loosey goosey datasheet. Nevertheless it will be very interesting to see the results of your test :smiley:

Yeah a data sheet is only as good as the people preparing it and how good the test for specs was. Also makes you wonder how tightly controlled is the manufacturing process and how much sampling of product is done to insure the specs are met.