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Fine Offset Pressure sensor

Discussion and questions about Cumulus weather station software version 1. This section is the main place to get help with Cumulus 1 software developed by Steve Loft that ceased development in November 2014.
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geowarm
Posts: 16
Joined: Wed 06 Jul 2011 6:41 am
Weather Station: W-8681 Solar
Operating System: XP
Location: Kidderminster
Contact:

Fine Offset Pressure sensor

Post by geowarm »

I have a Fine Offset with Solar W-8681 station and run V1.9.4 Cumulus on an old XP laptop.
The pressure reading has been absent for some time - static at 1013.2 on the display console and everywhere else.
So that I can home in on this issue can anyone tell me which hardware module in the weather station has the sensor?

I assume it's in the display console.

Strange thing is I have a second console which produces 1013.2 pressure reading too. With nothing connected to it.
In desperation I've even read the Fine Offset instruction manual, but I can't shift the static 1013.2 value.

Geo
www.mecol.co.uk/weather/index.htm

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mcrossley
Posts: 8313
Joined: Thu 07 Jan 2010 9:44 pm
Weather Station: Davis VP2/WLL
Operating System: Buster Lite rPi
Location: Wilmslow, Cheshire, UK
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Re: Fine Offset Pressure sensor

Post by mcrossley »

The pressure sensor is in the console.
Is it a coincidence that 1013.2 is standard atmospheric pressure?

geowarm
Posts: 16
Joined: Wed 06 Jul 2011 6:41 am
Weather Station: W-8681 Solar
Operating System: XP
Location: Kidderminster
Contact:

Re: Fine Offset Pressure sensor

Post by geowarm »

The 1013.2 reading is rel. hpa - the abs pressure reading is zero.
I'm a bit confused as to what rel/abs mean to be honest.
But you've hit on the issue I think.

sfws
Posts: 988
Joined: Fri 27 Jul 2012 11:29 am
Weather Station: Combination Mix of FO stations
Operating System: R Pi OS

Re: Fine Offset Pressure sensor

Post by sfws »

geowarm wrote:
Tue 04 May 2021 6:34 pm
I'm a bit confused as to what rel/abs mean to be honest.
The absolute pressure is what your sensor measures, stores in the circular memory, and then outputs to Cumulus.

The relative pressure adds a constant, (you have set in either the Fine Offset console or in Cumulus.ini), to convert that measurement to its equivalent value, if pressure was measured at sea level. This, adjusting for altitude, allows you to compare your measurements relative to those at other locations.

This forum topic includes photographs of various Fine Offset models, trying to identify which component is what sensor.

geowarm
Posts: 16
Joined: Wed 06 Jul 2011 6:41 am
Weather Station: W-8681 Solar
Operating System: XP
Location: Kidderminster
Contact:

Re: Fine Offset Pressure sensor

Post by geowarm »

Thanks for clarification of abs/rel

So I seem to have two consoles each with the same pressure sensor fault. Extraordinary.

I have two btw because I bought a second station some 10 years back for spares. That proved to be a good move as I've had to use several of the spares. The only duff spare seems to be the consol but I used that consol years ago over a long period and it all worked. I wonder if there is some age related failure in the pressure sensor?

On the spare consol, I cleared out the memory and restored factory defaults but it still shows zero abs pressure.

So I'm now thinking of adding some javascript to indexT.html to pull in a pressure reading off the internet and somehow merge it.
Or I could buy a third weatherstation!

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