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Randy...I brought it up before, but have you ever tried an SHT75? If you're really suspicious about Davis' handling of the sensors it may be worth giving a sensor soldered at the Sensirion factory a try. I'm sure you have an old Davis SHTxx that you can sacrifice to solder directly to the 75 pins or insert into an acceptable connector.
YesQuote from: dendrite on July 22, 2018, 04:22:59 PMRandy...I brought it up before, but have you ever tried an SHT75? If you're really suspicious about Davis' handling of the sensors it may be worth giving a sensor soldered at the Sensirion factory a try. I'm sure you have an old Davis SHTxx that you can sacrifice to solder directly to the 75 pins or insert into an acceptable connector.Correct me if I'm wrong, Randy, but didn't you say that your 15s were fried too when it came to humidity?
This is interesting...drier air moved into central Alabama today.Airport that is 15 miles N of me. 88/64Acurite Temp/Hum sensor with lightning detector 89/65.5Davis VP 2 with -8% offset 88/67.7
Quote from: jgentry on July 22, 2018, 05:15:52 PMThis is interesting...drier air moved into central Alabama today.Airport that is 15 miles N of me. 88/64Acurite Temp/Hum sensor with lightning detector 89/65.5Davis VP 2 with -8% offset 88/67.7So chasing humidity too....
Quote from: dendrite on July 22, 2018, 04:22:59 PMRandy...I brought it up before, but have you ever tried an SHT75? If you're really suspicious about Davis' handling of the sensors it may be worth giving a sensor soldered at the Sensirion factory a try. I'm sure you have an old Davis SHTxx that you can sacrifice to solder directly to the 75 pins or insert into an acceptable connector.So remove sht15 chip and solder SHT75 in its place? How is the 75 with humidity? Does it have the same high bias even after reconditioning the 31 nothing really changed. Quote from: openvista on July 22, 2018, 04:52:22 PMYesQuote from: dendrite on July 22, 2018, 04:22:59 PMRandy...I brought it up before, but have you ever tried an SHT75? If you're really suspicious about Davis' handling of the sensors it may be worth giving a sensor soldered at the Sensirion factory a try. I'm sure you have an old Davis SHTxx that you can sacrifice to solder directly to the 75 pins or insert into an acceptable connector.Correct me if I'm wrong, Randy, but didn't you say that your 15s were fried too when it came to humidity?Yes it's not much better.
Quote from: ValentineWeather on July 22, 2018, 05:36:18 PMQuote from: jgentry on July 22, 2018, 05:15:52 PMThis is interesting...drier air moved into central Alabama today.Airport that is 15 miles N of me. 88/64Acurite Temp/Hum sensor with lightning detector 89/65.5Davis VP 2 with -8% offset 88/67.7So chasing humidity too.... Dewpoint (DP) is calculated from the TEMP and RH values, so if either one is off, so too will be the calculated DP value. However, TEMP is usually far more accurate than RH, so DP errors can usually be traced back to the errant RH values more than TEMP values.
Quote from: jgentry on July 22, 2018, 05:15:52 PMThis is interesting...drier air moved into central Alabama today.Airport that is 15 miles N of me. 88/64Acurite Temp/Hum sensor with lightning detector 89/65.5Davis VP 2 with -8% offset 88/67.7Yikes! By my calculations that's a >20% absolute humidity error, assuming the dew point of 67.7 is actually 75.7 without the offset.
I forgot to put in my little acurite is showing 86/64 humidity is way off for a 31 sensor chip.
Quote from: jerryg on July 22, 2018, 06:20:42 PMI forgot to put in my little acurite is showing 86/64 humidity is way off for a 31 sensor chip.Because it's not reading high? My 2 acurite units are normal on humidity.
No because it is reading lower than all the other sensors i have, by 5% or more. I guess i will have to put it in the bag and see how close it comes to 75%.
Quote from: ValentineWeather on July 22, 2018, 06:53:31 PMQuote from: jerryg on July 22, 2018, 06:20:42 PMI forgot to put in my little acurite is showing 86/64 humidity is way off for a 31 sensor chip.Because it's not reading high? My 2 acurite units are normal on humidity. Have you thought about, perhaps, leaving one of them outside in the shade during days without precipitation? I wonder how long it would stay in calibration?
I put mine out when light fog was expected and it pegged out at 99 and main station was reporting 97 and that was the general high for around the area. Not too impressed with my cheap meter, i might have to take it apart and see if it does have a 31 and how it is mounted.
From my testing the Davis sensors all read high. I didn't use a bag but going from my other instruments and ASOS the acurite is correct. That was my point how can I have 2 acurite sht31's read normal with instruments and ASOS and then have 3 Davis sensors all high. That's where the idea of contamination came in with 2 different companies mounting differently onto boards.