I’ve been running WD 10.375.123 for about a year and we’ve always thought the wind speed was reading high. The hardware is a Vaisala WTX530 that has the ultrasonic speed and direction. The operating system is Windows 10.
We used a anemometer on a 20’ stick and Weather Display is indicating speeds about twice the hand held device.
I tried to put in negative offsets for the wind speed but that doesn’t seem to have any effect, in some places you can’t put in a negative offset. From the Control Panel I tried to set both negative and positive offsets with no effect.
From the debug I get a string from the station as follows
Humidity= 54.8P raw
0R0,Dm=192D,Sm=35.1K,Ta=8.9C,Ua=54.8P,Pa=999.3H,Rc=42.32M,Tr=185.0C,Ra=0.0M,Sl=0.000566V,Sr=-0.589232V,Rt=2322.0R,Th=14.6C,Vh=22.5V
The Sm parameter shows 35.1K which should show in WD as 35.1km/h, but instead it shows 65km/hr. It as if the WD software thinks it’s getting the raw speed from the station in Knots. Changing the units in the software works on the display but doesn’t fix the speed error. For 35.1 changing to M/S gives me 18.1.
I’ve been through all the places I can think of to either get the software to recognize the input is in Km/Hr or put in a correction factor but have been unsuccessful. I installed WD 10.375.133 but when I did that I couldn’t get the software to communicate with the station, all the serial port settings were OK so I ended up reinstalling .123
The WTX530 is a nice piece of kit but I know it’s not the most popular station due the cost. Ours is located in a tough spot and it had stood up well. It displays at Goderich Port Weather Data
It’s hard to access the station itself to edit the settings since it requires a manlift but the computer is readily accessible.
I have only had experience with the 520s and 510s but believe the basic design and even the hardware is the same or similar.
I have always noted that even in the most quiet of settings (while testing indoors) that the speed is never zero, always 0.4 to 0.6 mph at the least. Another forum contact some years ago had a factory new 520 that was similar and I recall one email from him a few years ago that said he finally saw a 0.0 speed for a short while.
It is difficult to know if something is off by a few mph, but double is really off, if your other sensor was close to accurate.
Weather Display can only show what data it is receiving. There are, of course, the tweaks it allows users to build in for all sorts of sensors if they happen to be a little off for say temp, humidity, etc.
Have you looked at the data stream coming in from the 530 to see if the numbers in that stream are reading high, rather than for some odd reason the interface software is giving WD a higher number than really is being reported?
I also assume that the 530 was very carefully installed and the three transmitter/receivers were not pinched together towards each other even the slightest bit? They shouldn’t be, but the physics behind the measurement would show a higher value for wind speed if the distance that the calibration was done at is now closer yet still falls within the cutoffs for expected time of flight of the pulse from transducer to transducer.
Dale - In my original post I did include the data stream and I’m fairly sure WD is treating the wind speed as knots when it’s actually km/H. That’s a factor of 1.85. If I could just use a negative offset to correct the reading that would be acceptable.
It would be an interesting experiment to change the WTX530 to output knots instead of km/h and see if WD showed the correct speed. The station is about 15 meters from the ground and you need a manlift to access it. You can only set the station up by using the special cable to it’s programming port. With the rental cost & trucking of the lift that experiment would cost over $1k. I’d spend the money if I was sure it would solve the problem.
A speed error of ~1km/h in still air isn’t an issue. I don’t think the three transducers could of moved since they are molded into the plastic housing and you’d have to break them off to move them appreciably.
I’m still pretty impressed with the capabilities of the WD software, this one issue is the only problem.
Thanks Brian, that’s sort of what I guessed. Is there any chance that a bug is causing WD to think a K is Knots instead of km/h and do it’s calculation from that? According to the Vaisala documentation knots is represented by a N.
I realize if that is the case it’s a hassle to fix for such a small installed base of these stations. Is there something I’m doing wrong to offset the wind speed by -55%? I can’t get the wind speed offsets to have any effect, positive or negative.
Thanks Brian, that worked. Now the wind speed from the debug string matches the displayed wind speed. I had a little trouble getting the software to initiate the serial link but I changed to baud rate from 9600 to 19.2k, saved that and then changed it back and the communications started up.