Topic: SHT31 offset

[CW2274]

Getting a little tired of my dew landing me in QC jail so I'd thought I bump the humidity up 1% and see how it looks after we get a little more wet. Well low and behold my temp offset had somehow been canceled out and was reading with a zero correction factor. I was/am dumbfounded how this occurred, and wondering how long it's been this way. Anyway those of us with the offset may want to check....zero idea how it happened.

[WxLover16]

Getting a little tired of my dew landing me in QC jail so I'd thought I bump the humidity up 1% and see how it looks after we get a little more wet. Well low and behold my temp offset had somehow been canceled out and was reading with a zero correction factor. I was/am dumbfounded how this occurred, and wondering how long it's been this way. Anyway those of us with the offset may want to check....zero idea how it happened.

So that means all along your .9 calibration offset had been auto-corrected to 0 and you've been reading .9 too warm?

[ValentineWeather]

Bumping humidity up 1-2% is still within range of +/-  2% error so if it helps do it. 

Not sure what happened with the -.9 offset needed for pre 2016 transmitters and sht31. Once -.9F is back in humidity will drop on its own so you may not need to add the humidity correction.

Sucks you went into the summer without the correction needed. 

[CW2274]

Getting a little tired of my dew landing me in QC jail so I'd thought I bump the humidity up 1% and see how it looks after we get a little more wet. Well low and behold my temp offset had somehow been canceled out and was reading with a zero correction factor. I was/am dumbfounded how this occurred, and wondering how long it's been this way. Anyway those of us with the offset may want to check....zero idea how it happened.

So that means all along your .9 calibration offset had been auto-corrected to 0 and you've been reading .9 too warm?

Yes. The problem is how long was "all along". No way to check either.

[WxLover16]

Bumping humidity up 1-2% is still within range of +/-  2% error so if it helps do it. 

Not sure what happened with the -.9 offset needed for pre 2017 transmitters and sht31. Once -.9F is back in humidity will drop on its own so you may not need to add the humidity correction.

Sucks you went into the summer without the correction needed.

It's actually pre 2016 transmitters. I have a Feb 2016 transmitter that didn't need the offset.

[CW2274]

Once -.9F is back in humidity will drop on its own so you may not need to add the humidity correction.

I did actually consider this, but will give the 1% a try first. Like I stated in another thread, once my 31 gets less than 3%, it bottoms out the dew pretty fast.
Now I'm gonna be paranoid over the offset. How often will I look until I'm satisfied it was somehow a fault of my own (which I'm sure it was, I guess).

[ValentineWeather]

Bumping humidity up 1-2% is still within range of +/-  2% error so if it helps do it. 

Not sure what happened with the -.9 offset needed for pre 2017 transmitters and sht31. Once -.9F is back in humidity will drop on its own so you may not need to add the humidity correction.

Sucks you went into the summer without the correction needed.

It's actually pre 2016 transmitters. I have a Feb 2016 transmitter that didn't need the offset.

Yes I meant pre 2016, thanks.

[WheatonRon]

Getting a little tired of my dew landing me in QC jail so I'd thought I bump the humidity up 1% and see how it looks after we get a little more wet. Well low and behold my temp offset had somehow been canceled out and was reading with a zero correction factor. I was/am dumbfounded how this occurred, and wondering how long it's been this way. Anyway those of us with the offset may want to check....zero idea how it happened.

Moral of the story? You should send Ryan Wilhour a check and buy a new PCBA (Davis part No. 7345.951, about $100) so you won't need the offset adjustment--I did and I am not usually not in QC jail! Then again, I did go to QC jail yesterday because one upload interval, an upload to CWOP showed wind at 327mph! MesoWest correctly sent me to QC jail for that one interval. Not sure if that is an CWOP issue or a WeatherLink issue, but since it only happened once I guess I will live with it. Really weird though! Not even sure if wind has ever been recorded at that speed!

[CW2274]

Getting a little tired of my dew landing me in QC jail so I'd thought I bump the humidity up 1% and see how it looks after we get a little more wet. Well low and behold my temp offset had somehow been canceled out and was reading with a zero correction factor. I was/am dumbfounded how this occurred, and wondering how long it's been this way. Anyway those of us with the offset may want to check....zero idea how it happened.

I am not usually not in QC jail!

Then again, I did go to PC jail because one upload interval yesterday, an upload to CWOP showed wind at 327mph! MesoWest correctly sent me to QC jail. Not sure if that is an CWOP issue or a WeatherLink issue, but since it only happened once I guess I will live with it. Really weird though! Not even sure if wind has ever been recorded at that speed!

You don't have humidity below 3% either.

Have seen 327mph many times. When there's a "hiccup" in the transmission, this is what sometimes is displayed. No idea why.
As far as wind speed, I believe the doppler measured velocity of 308mph in the EF5 that just missed my dad's house in Bridge Creek, OK on 5/3/99 still holds the record.

[Bashy]

HI guys, whats this 0.9 correction about please? I have the SHT31 (checked the other day) but i have not made any
console or Envoy corrections??

[CW2274]

HI guys, whats this 0.9 correction about please? I have the SHT31 (checked the other day) but i have not made any
console or Envoy corrections??

Specifically, reply #6. http://www.wxforum.net/index.php?topic=32158.0

[Bashy]

Thanks, for the reply, so if i read that right, i need to check my sim board revision?

[CW2274]

Thanks, for the reply, so if i read that right, i need to check my sim board revision?

Yes, but I think your console can supply the info you need also if you bought it along with your ISS. Search the site as this has been discussed often and you'll find what you need or someone will chime in with exact info.

[Bashy]

Here's mine,

[johnd]

Here's mine,

Don't worry about it. Offset is only relevant if mixing SHT31 with pre-AS SIM boards (or vice versa, ie SHT1x sensor with AS or later revision SIM board). If SHT31 is connected to an AS or later SIM then the offset is automatically taken care of by the SIM and the transmitted temperature values are fully accurate.

[Bashy]

Here's mine,

Don't worry about it. Offset is only relevant if mixing SHT31 with pre-AS SIM boards (or vice versa, ie SHT1x sensor with AS or later revision SIM board). If SHT31 is connected to an AS or later SIM then the offset is automatically taken care of by the SIM and the transmitted temperature values are fully accurate.

Thanks Johnd, appreciate it