Author Topic: HOWTO: Adjust WeeWX when upgrading a Davis temp/humidity sensor  (Read 1118 times)

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Offline noctilucent

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This is pretty straightforward but I figured I'd post it here to get it online and Google-able if someone else needs to do it: When replacing the temp/humidity sensor on a Davis weather station and going from an older 7346-166 (Sensiron SHT15) to the current 7346.070 (Sensiron SHT31), you need to add a temperature offset of -0.5C for the new sensor.  To do this:
Code: [Select]
sudo vi /etc/weewx/weewx.conf
/\[\[Correct
  outTemp = outTemp - 0.5
:x
sudo /etc/init.d/weewx restart
Keep an eye on whatever you're using to monitor the weather station stats and you'll see it jump by around 0.5C at the next update.

Offline mcrossley

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Re: HOWTO: Adjust WeeWX when upgrading a Davis temp/humidity sensor
« Reply #1 on: July 04, 2021, 12:03:27 PM »
You should make the adjustment in the station, then the console will read correctly - along with any other software like weewx that reads from it. It also means the dew point and wind chill will be calculated correctly.
Mark

Offline noctilucent

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Re: HOWTO: Adjust WeeWX when upgrading a Davis temp/humidity sensor
« Reply #2 on: July 05, 2021, 04:55:25 AM »
How do you make the adjustment in the station?  It's a sealed, non-user-adjustable device isn't it?

Offline johnd

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Re: HOWTO: Adjust WeeWX when upgrading a Davis temp/humidity sensor
« Reply #3 on: July 05, 2021, 07:23:35 AM »
Station = console + ISS (+ any supplementary transmitters/sensors). Offset adjustments are made to the console.

If you're not using a console, eg Weatherlink Live instead, then look at Advanced Settings in Device configuration on the browser interface online.
Prodata Weather Systems
Prodata's FAQ/support site for Davis stations
Includes many details on 6313 Weatherlink console.
UK Davis Premier Dealer - All Davis stations, accessories and spares
Cambridge UK

Sorry, but I don't usually have time to help with individual issues by email unless you are a Prodata customer. Please post your issue in the relevant forum section here & I will comment there if I have anything useful to add.

Offline noctilucent

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Re: HOWTO: Adjust WeeWX when upgrading a Davis temp/humidity sensor
« Reply #4 on: July 05, 2021, 07:25:50 AM »
I'm using an SDR to read data directly from the ISS, there's nothing between the ISS and WeeWX.

Offline johnd

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Re: HOWTO: Adjust WeeWX when upgrading a Davis temp/humidity sensor
« Reply #5 on: July 05, 2021, 07:29:15 AM »
I'm using an SDR to read data directly from the ISS, there's nothing between the ISS and WeeWX.

Fair enough - your solution obviously applies then. But anyone using a more conventional station set-up might find themselves making the temperature correction twice over.
Prodata Weather Systems
Prodata's FAQ/support site for Davis stations
Includes many details on 6313 Weatherlink console.
UK Davis Premier Dealer - All Davis stations, accessories and spares
Cambridge UK

Sorry, but I don't usually have time to help with individual issues by email unless you are a Prodata customer. Please post your issue in the relevant forum section here & I will comment there if I have anything useful to add.

Offline noctilucent

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Re: HOWTO: Adjust WeeWX when upgrading a Davis temp/humidity sensor
« Reply #6 on: July 05, 2021, 07:43:10 AM »
Fair enough - your solution obviously applies then. But anyone using a more conventional station set-up might find themselves making the temperature correction twice over.

Ah, good point, if you're already correcting via the ISS read process then don't correct a second time in WeeWX.

Offline N0NB

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Re: HOWTO: Adjust WeeWX when upgrading a Davis temp/humidity sensor
« Reply #7 on: November 27, 2023, 03:45:56 AM »
According to the 7346.070 page at Scaled Instruments, ISS transmitters with a manufacturing code of 'AS' or later already compensate for the new sensor in their firmware.

I did the upgrade in my old ISS a couple of weeks ago and adjusting the console offset is described beginning near the bottom of page 26 of the console manual.  This applied the correction to the displayed temperature on the console and to the serial data read by WeeWx so I did not have to use the WeeWx offset.