Topic: Field study thermometer shields FARS 7755, Passive 7714, & new METEOSHIELD

[SnowHiker]

The following reconditioning
procedure may bring the sensor back to calibration state:

Just keep the word "may" in mind. It may bring it back, but then it may not.  Worth a try if the sensor is already contaminated.

[ValentineWeather]

Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.

Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.

As in Permanently ruin it ? 

Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 – 105°C at < 5%RH for 10h
Re-Hydration: 20 – 30°C at ~ 75%RH for 12h

I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125° even though they say 105°c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

[Bobvelle]

Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.

Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.

As in Permanently ruin it ? 

Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 – 105°C at < 5%RH for 10h
Re-Hydration: 20 – 30°C at ~ 75%RH for 12h

I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125° even though they say 105°c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

I assume this is the whole assembly? i.e. the PCB and 6c cable attached? If so, what did you do with the cable during baking to keep it of the bottom?

[openvista]

Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

Sounds like a mixed bag, at best. But it's good to have someone else attempt it. More data, either way.

[Bobvelle]

Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

Sounds like a mixed bag, at best. But it's good to have someone else attempt it. More data, either way.

Just to be clear. I'm baking a SHT-11 that's about 5 or 6 years old and hasn't been in use for 2 years. I plan to put in use tomorrow or the next day as a second temp/hum station. If memory serves, it never read over 98% RH. But I wasn't watching for it until I replaced it with my first 31. That 31 would reach 100% RH on only a few occasions, and that was early in it's life.
I may bake it next.

[ValentineWeather]

Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.

Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.

As in Permanently ruin it ? 

Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 – 105°C at < 5%RH for 10h
Re-Hydration: 20 – 30°C at ~ 75%RH for 12h

I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125° even though they say 105°c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

I assume this is the whole assembly? i.e. the PCB and 6c cable attached? If so, what did you do with the cable during baking to keep it of the bottom?

Cable is attached but leave hanging out. I remove sensor if attached to board that slides into 24 hr. fars sensor chamber and remove filter cap.

[ValentineWeather]

Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

Sounds like a mixed bag, at best. But it's good to have someone else attempt it. More data, either way.

Yeah if sensor never did reach 98% baking won't help is what I've found.

[Bobvelle]

Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.

Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.

As in Permanently ruin it ? 

Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 – 105°C at < 5%RH for 10h
Re-Hydration: 20 – 30°C at ~ 75%RH for 12h

I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125° even though they say 105°c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

I assume this is the whole assembly? i.e. the PCB and 6c cable attached? If so, what did you do with the cable during baking to keep it of the bottom?

Cable is attached but leave hanging out. I remove sensor if attached to board that slides into 24 hr. fars sensor chamber and remove filter cap.

Yeah, I thought about that right after I posted, let the cord hang out. I cut a 1 inch length off a paper towel core and ran the cable through it and set the lid on it. It's baking now, but taking a while to get to temp. I remembered too that I have an industrial oven temp meter w/probe that I used for baking Cerakote. Its perfect for this.
Also through some desiccant packs in with it... maybe it will help soak up some humidity.
Thanks for all the Info!

[jerryg]

Well i pulled the trigger on what is supposed to be a really great passive shield from Barani. I am getting the pro and standard shields to compare the two against each other and of course the Davis fars. It sure would be nice to have a passive shield and eliminate the fan and batteries that go with the fars shield. One of the things i will be checking is how the sensor fits into the shields the pro only has an opening of 1.6 inches and the standard has an opening of 2.6 which should allow the sensor to fit. Here is the url to the two shields https://www.allmeteo.com/solar-radiation-shield/

[SLOweather]

Probably not. As I recall, you can bake the sensor to recondition it. See the Sensirion handling docs and spec sheets.

Absolutely, 'out-gassing' of paint volatile's will detrimentally affect RH sensor accuracy.

As in Permanently ruin it ? 

Thanks, Found it:  (This is for the SHT-15)
1.4 Reconditioning Procedure
As stated above extreme conditions or exposure to solvent
vapors may offset the sensor. The following reconditioning
procedure may bring the sensor back to calibration state:
Baking: 100 – 105°C at < 5%RH for 10h
Re-Hydration: 20 – 30°C at ~ 75%RH for 12h

I wonder how low Rh my oven gets? Likely not <5%. Not in a Gulf Coast region household oven anyway.
.

I used crock pot SLOweather's idea.  I just made a tin foil tent/platform keeping sensor off bottom and baked 10 hours keeping lid cracked open 1/2 to 3/4". Using temperature gun I was between 110-125c. Spark Fun does all sensor baking at 125° even though they say 105°c in reconditioning literature.
Some of my sensors only maxed at 96% new baking didn't correct. If sensor reached 98+ new and stopped baking may restore to original performance.

I assume this is the whole assembly? i.e. the PCB and 6c cable attached? If so, what did you do with the cable during baking to keep it of the bottom?

Cable is attached but leave hanging out. I remove sensor if attached to board that slides into 24 hr. fars sensor chamber and remove filter cap.

Yeah, I thought about that right after I posted, let the cord hang out. I cut a 1 inch length off a paper towel core and ran the cable through it and set the lid on it. It's baking now, but taking a while to get to temp. I remembered too that I have an industrial oven temp meter w/probe that I used for baking Cerakote. Its perfect for this.
Also through some desiccant packs in with it... maybe it will help soak up some humidity.
Thanks for all the Info!

FWIW, you should be able to find a site that will calculate absolute humidity (moisture content of the air in er, mass per unit volume, and the use that and the temperature inside the crock pot oven to back calculate the RH in there.

[SLOweather]

I used crock pot SLOweather's idea. 

Great... Is that my new nickname around here, Crock Pot SLOweather?

[ValentineWeather]

Well i pulled the trigger on what is supposed to be a really great passive shield from Barani. I am getting the pro and standard shields to compare the two against each other and of course the Davis fars. It sure would be nice to have a passive shield and eliminate the fan and batteries that go with the fars shield. One of the things i will be checking is how the sensor fits into the shields the pro only has an opening of 1.6 inches and the standard has an opening of 2.6 which should allow the sensor to fit. Here is the url to the two shields https://www.allmeteo.com/solar-radiation-shield/

So you think the 2.6" will fit a SHT31? I'm also very interested same reason. I should contact them since we were working together on this originally.

[jerryg]

Well it looks like it will by diameter measurement just not sure if the big filter will make it tight. I have looked at a bunch of the sensor boards and it looks like the board could be made smaller by removing the extra to the left of where the shield snaps in, there does not appear to be any circuit printed there and it would come close to fitting in the pro shield with a factory filter which is so much smaller. It sure would be nice to get rid of all the fars stuff and it will be interesting to see how it handles the high humidity problem also.

[ValentineWeather]

Well it looks like it will by diameter measurement just not sure if the big filter will make it tight. I have looked at a bunch of the sensor boards and it looks like the board could be made smaller by removing the extra to the left of where the shield snaps in, there does not appear to be any circuit printed there and it would come close to fitting in the pro shield with a factory filter which is so much smaller. It sure would be nice to get rid of all the fars stuff and it will be interesting to see how it handles the high humidity problem also.

I just sent Richard Toth<richard.toth@baranidesign.com>;Jan Barani<jan@baranidesign.com>; email asking if it will fit.

[jerryg]

Another nice thing about the shield is your can mount it away from the Davis stuff if you needed to just by using a straight thru jumper and a cat splice. I just made up my new sht75 sensor the other day and made it to fit the pro opening with extra long cable to be able to mount the shield on my tower next to the iss. The 75 has been looking real good in readings and response time. When they get here i will probably use the three 31 sensors because they are nearly identical in temperature readings and that is what the testing is all about, low to no wind and no temp spikes would be great.

[CW2274]

Well i pulled the trigger on what is supposed to be a really great passive shield from Barani. I am getting the pro and standard shields to compare the two against each other and of course the Davis fars.

They were on here when this came out and it looks promising. Thing I don't like is there claim to be as good or better than aspirated shields. Well, what aspirated shields? Just because a PWS has a fan doesn't make a bad shield good, that's for sure. They do do a comparison against an aspirated VP2, but the graph colors are so close together it makes it damn near impossible to distinguish between the two, but I get the point, they're close. That being said, they leave out one tiny little factor, wind speed during the test. Kinda makes a difference.
Look forward to your comparisons.

[jerryg]

It should be interesting to see how they compare against each other as well as the fars. I know when the wind is blowing the standard shield did real well against the fars but as the wind slowed down then the spikes started showing up. It will really be interesting to see how the two compare against each other too. Now all i have to do is sit here a wait for them to show up, that is the hard part lol.

[CW2274]

Now all i have to do is sit here a wait for them to show up, that is the hard part lol.

Yeah, it's been Christmas for a lot of you guys around here, buying stuff left and right, kinda jealous.... Actually, I'm seriously considering picking up a psycho-dyne, as CW7491 has, and see if the drier air here has lessened the wet bias and/or premature aging, as I'm leaning to believe it has.

[Old Tele man]

Now all i have to do is sit here a wait for them to show up, that is the hard part lol.

Yeah, it's been Christmas for a lot of you guys around here, buying stuff left and right, kinda jealous.... Actually, I'm seriously considering picking up a psycho-dyne, as CW7491 has, and see if the drier air here has lessened the wet bias and/or premature aging, as I'm leaning to believe it has.

BE VERY CAREFUL disassembling your FARS plates! With only 6.3 years use, mine crumbled in my hand as I replaced fan...replacement plates ordered from SI.

[CW2274]

Now all i have to do is sit here a wait for them to show up, that is the hard part lol.

Yeah, it's been Christmas for a lot of you guys around here, buying stuff left and right, kinda jealous.... Actually, I'm seriously considering picking up a psycho-dyne, as CW7491 has, and see if the drier air here has lessened the wet bias and/or premature aging, as I'm leaning to believe it has.

BE VERY CAREFUL disassembling your FARS plates! With only 6.3 years use, mine crumbled in my hand as I replaced fan...replacement plates ordered from SI.

I replaced my top two plates and solar PCB cover about this time last year due to this exact issue, except I managed 10 years outta mine. The bottom plates are still like new. Only structural replacement parts I've ever needed for my VP2.

[Old Tele man]

Now all i have to do is sit here a wait for them to show up, that is the hard part lol.

Yeah, it's been Christmas for a lot of you guys around here, buying stuff left and right, kinda jealous.... Actually, I'm seriously considering picking up a psycho-dyne, as CW7491 has, and see if the drier air here has lessened the wet bias and/or premature aging, as I'm leaning to believe it has.

BE VERY CAREFUL disassembling your FARS plates! With only 6.3 years use, mine crumbled in my hand as I replaced fan...replacement plates ordered from SI.

I replaced my top two plates and solar PCB cover about this time last year due to this exact issue, except I managed 10 years outta mine. The bottom plates are still like new. Only structural replacement parts I've ever needed for my VP2.

Yep, those are the plates that fell apart as I handled them. So much for being UV-resistant -- NOT!

[Bobvelle]

I made a mistake in an earlier post and corrected it. The sensor I was/am reconditioning is not a SHT-15 it is in an 11.

I guess I wasn't very clear  Sorry bout dat

[ValentineWeather]

Have a new shield to test in few weeks. The Metoshield standard will fit the Davis sensor now, no mention if this was with or without filter cover.

If interested in going FARSLESS (I am), I'll be testing these units when I finally get one or two in hand. 
It will be a couple weeks before in stock however in meantime I'll continue testing the Davis 7714.

[jgentry]

Have a new shield to test in few weeks. The Metoshield standard will fit the Davis sensor now, no mention if this was with or without filter cover.

If interested in going FARSLESS (I am), I'll be testing these units when I finally get one or two in hand. 
It will be a couple weeks before in stock however in meantime I'll continue testing the Davis 7714.

Keep us posted. Would be interested to see how that shield compares to the FARS & Davis passive shield.

[ValentineWeather]

Will do, rest of the week looks better for testing 7714 also. Hoping I have at least 1-2 days of light winds so can get some real numbers.

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