WMR88 pressure setting

[bus_ter]

Hello,

I've just bought a Oregon Scientific WMR88 and I've been setting it up. Is there a way to set the absolute pressure? Normally weather stations let you select the pressure based on a known local value and it then tracks the relative changes giving you an accurate figure- well that's what I did with my last one. Can't seem to do that with this one. It's currently tracking 6mb below the local figure. I did notice there is a height setting you can enter (I put in my local height of 40m) which didn't make any significant difference. The height setting lets you set a negative number. Should I simply set this to a false height to try and get a correct local reading?

Thanks!

PS - Any tips before I mount the external sensors would be great too!

[bus_ter]

As a workaround I've set my altitude 40m higher than it should be to get a pressure setting that matches my local stations.

[bus_ter]

Just some further updates regarding my setup of the WMR88 for future reference of anyone who may be reading this in the future.

To correctly calibrate my WMR88 to match more accurate figures I had to apply the following calibration corrections

1) Set the stations alt to +40m above my actual height above sea level (I'm 40m and set 80m)
2) Apply a temperature offset of +0.5C in Cumulus
3) Make sure Cumulus is set to calculate wind chill temp
4) Apply a factor of *2 for wind speed and gust speed (however my low siting height of the anemometer may be a contribution factor to the low readings)
5) spontaneous wind direction and speed is all over the place, however if you set cumulus to use average these the readings are acceptable

It may not be working when you find this but it should be uploading data here: http://www.wunderground.com/weatherstat ... =ISEATOND2

[steve]

I don't think many people have these, which is probably why no help was forthcoming. Now that you've done some calibration, how are you finding it? They're going for quite a good price at the moment, so aside from the lack of a data logger, I'm wondering if they are a good buy as an alternative to Fine Offset stations.

[thegasman]

I've just ordered one one of these for under £80 online. At this price it looks like a no-brainer.
I keep my laptop on 24/7, so the lack of a datalogger is not an issue for me.
If it's troublesome I'll ditch it and invest in a 'quality' unit, if it works ok I plan to buy a solar charger for the anemometer so I don't have to get up on the roof every year!

Martin

[RussP]

New user here.

I bought a WMR88 a few days ago. My first weather station so cannot compare it to anything else.

There is a setting on the console to change something to do with the pressure setting. Not got the manual to hand so not sure what it does, all I can remember is that it changes in steps of 10. Think you use 'select' to get to get the cursor to the baramoter/rain/uv section then press 'mode' to select the baramoter setting. Then press and hold 'mode'.

My nearest station is Blackpool Airport (.5mile away) and my pressure reading on the few times I've compared is showing about 5mb below the airports.
Airport seems to show the temp as a rounded value, so I'm reading a little below. My last reading is showing 7.3 compared to the airports 8
The airport doesn't seem to report rain, so no idea how I'm doing on that, but I am getting readings (5.1mm in the last hour)

Wind, I'm well under due to siting issues. Only got it mounted above the roof of my shed so about 3m and house to the North and South. I'll try and get it to the roof sometime.

I'm impressed with it so far. Also loving Cumulus.

My weather data : http://www.bfc-toolbar.co.uk/weather/index.htm

[bus_ter]

New user here.


There is a setting on the console to change something to do with the pressure setting. Not got the manual to hand so not sure what it does, all I can remember is that it changes in steps of 10. Think you use 'select' to get to get the cursor to the baramoter/rain/uv section then press 'mode' to select the baramoter setting. Then press and hold 'mode'.

My nearest station is Blackpool Airport (.5mile away) and my pressure reading on the few times I've compared is showing about 5mb below the airports.

Yes indeed! Look above. This is the reason I started the thread and ultimately answered my own question. The setting you describe is for calibrating the barometer. Instead of just setting your local pressure as a reference it wants you to put in your altitude above sea level (in meters). I had to put in a setting of 80m (which is 40m above my actual height) to get it to give a reading that matches my local stations. Be aware that when you change this setting that it will not update your pressure value until the next reading. This could be anything up to 15 minutes.

Airport seems to show the temp as a rounded value, so I'm reading a little below. My last reading is showing 7.3 compared to the airports 8

Again look above. I had to set an offset of +0.5C to get a reading that matched local stations and my other thermometers.

The airport doesn't seem to report rain, so no idea how I'm doing on that, but I am getting readings (5.1mm in the last hour)

That's a lot of rain! You need a mm of rain to tip the sensor and get a reading. I've found that drizzle will often not give a reading and you need a proper rain shower for it to register, and even then maybe 5-10mins before you get your first reading. However once it does it seems to match with my surrounding stations without the need of any offset.

Wind, I'm well under due to siting issues. Only got it mounted above the roof of my shed so about 3m and house to the North and South. I'll try and get it to the roof sometime.

ditto again. I used an offset of a multiplier of 2x to get values to match near surrounding stations. As I described above.

It's interesting that your reading 'errors' all match mine almost exactly. These might make good starting values for anyone who has just installed this station and are not matching nearby observations.

[bus_ter]

I don't think many people have these, which is probably why no help was forthcoming. Now that you've done some calibration, how are you finding it? They're going for quite a good price at the moment, so aside from the lack of a data logger, I'm wondering if they are a good buy as an alternative to Fine Offset stations.

Hi Steve,

Before this station I only had generic temp/pressure/humidity sensors. This is my first venture into wind and rain measurement. I'm quite happy with the station so far. I have an old Asus EEE netbook that is now running Cumulus 24/7. As such I have all the data logging I could want. The sensors seem to be a little off (as described in this thread), even my £20 Aldi ASCOT weather station is more accurate. However using the Cumulus offset calibration feature the values can be corrected and remain consistent. I assumed this was just variation with my unit, but it's interesting another user here has the same readings.

I like that all the sensors are independent and wireless. I don't like how the instruction manual describes placement of the sensors. It tells you to mount the wind sensor on the side of a fence or wall, which would obviously block all wind from one direction and mess up the readings. A pole is essential but not included. I bought a small mounting kit from B&Q for £7 (I'll post link below and take a photo of it installed). Also the temp/humidity sensor is not a type that comes with a solar shield of any sort and it suggests mounting it on a wall.

Longevity of the kit I have no idea. We're on week 2 here. I don't think I would pay the RRP of £150 or whatever but at 60% off it made for an affordable toy to play with.



http://www.diy.com/nav/fix/electrical/t ... et-9686653

[bus_ter]

I've just ordered one one of these for under £80 online. At this price it looks like a no-brainer.
I keep my laptop on 24/7, so the lack of a datalogger is not an issue for me.
If it's troublesome I'll ditch it and invest in a 'quality' unit, if it works ok I plan to buy a solar charger for the anemometer so I don't have to get up on the roof every year!

Martin

I posted a link in the general section at the end of last year showing how to buy it for £67.
https://cumulus.hosiene.co.uk/viewtopic.php?f=11&t=11154

Are you uploading data online?

Currently I'm on Wunderground: http://www.wunderground.com/weatherstat ... =ISEATOND2
and also using the Cumulus built in webpage: http://www.sdweather.unospace.net/

[thegasman]

I posted a link in the general section at the end of last year showing how to buy it for £67.
https://cumulus.hosiene.co.uk/viewtopic.php?f=11&t=11154

Are you uploading data online?

Currently I'm on Wunderground: http://www.wunderground.com/weatherstat ... =ISEATOND2
and also using the Cumulus built in webpage: http://www.sdweather.unospace.net/

I hadn't seen your post for £67, but I did get it from Maplins with the discount code.
It has just arrived today. It's pretty clear they have cut costs compared to the WMR968 I have been using up to now, but it is less than half the price. It all feels pretty flimsy. The console should be good for many years hopefully, the sensors will doubtless need repaired or replaced quite regularly, but they are cheap too!

I do indeed have my data online on Wundermap and at http://www.doonfootweather.x10.mx/cumulus. This is the data from my WMR968, should be changing to the WMR88 at the weekend hopefully.

With the correct altitude set in the console, my WMR88 is agreeing with the pressure reading from my WMR968, which I have previously checked with the met office on a high pressure day.