aag wind direction ds2450 weirdness

[ksdehoff]

Hello:

I've got a question about the wind direction sensor on the AAG wind instrument. I'm using mcs1wire to read and I get a total of 5 devices - 1 wind direction and 4 voltages. Using debugging I can see the 4 voltages changing but the actual wind direction does not update. Is there something obvious that I need to do to enable getting the direction to calculate based on the 4 wind direction voltages (typically 2 are less than .1 v, 1 is 0 and a 4th is 2.5ish).

Thanks much
Ken

 

[midon]

Your voltages don't seem to match any valid direction state. See the document "Calculating Wind Speed and Direction on the OWWS" located here.

Is it possible that your wind direction monitor is defective?

 

[Michael McSharry]

xapmcs1wire uses the following table lookup for the 16 positions. Voltages are evaluated with a tolerance of 0.25 volt. For a North reading the DS2450 voltages will be 0.06+/-0.25, 4.64+/-0.25, 4.64+/-0.25, 4.64+/-0.25 for A/D channels 1 to 4 respectively.

110 dirTable = Array("N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE", "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW", "N")
140 conv_table(0) = Array(0.06, 4.64, 4.64, 4.64)
150 conv_table(1) = Array(0.06, 0.06, 4.6, 4.6)
160 conv_table(2) = Array(4.64, 0.06, 4.64, 4.64)
170 conv_table(3) = Array(4.62, 0.06, 0.06, 4.6)
180 conv_table(4) = Array(4.64, 4.64, 0.06, 4.64)
190 conv_table(5) = Array(4.6, 4.6, 0.06, 0.06)
200 conv_table(6) = Array(4.64, 4.64, 4.64, 0.06)
210 conv_table(7) = Array(2.36, 4.62, 4.6, 0.06)
220 conv_table(8) = Array(2.38, 4.66, 4.66, 4.66)
230 conv_table(9) = Array(3.2, 3.2, 4.66, 4.64)
240 conv_table(10) = Array(4.66, 2.38, 4.66, 4.66)
250 conv_table(11) = Array(4.66, 3.18, 3.2, 4.64)
260 conv_table(12) = Array(4.66, 4.66, 2.38, 4.66)
270 conv_table(13) = Array(4.66, 4.66, 3.18, 3.18)
280 conv_table(14) = Array(4.66, 4.66, 4.66, 2.38)
290 conv_table(15) = Array(0.06, 4.62, 4.62, 2.34)

 

[ksdehoff]

So what would (0,3.6,3.6,0) be coming from? I don't see this in your array....is my board bad possibly - or perhaps there are stuck switches or the rotor isn't always activating a switch?

Ken

xapmcs1wire uses the following table lookup for the 16 positions. Voltages are evaluated with a tolerance of 0.25 volt. For a North reading the DS2450 voltages will be 0.06+/-0.25, 4.64+/-0.25, 4.64+/-0.25, 4.64+/-0.25 for A/D channels 1 to 4 respectively.

110 dirTable = Array("N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE", "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW", "N")
140 conv_table(0) = Array(0.06, 4.64, 4.64, 4.64)
150 conv_table(1) = Array(0.06, 0.06, 4.6, 4.6)
160 conv_table(2) = Array(4.64, 0.06, 4.64, 4.64)
170 conv_table(3) = Array(4.62, 0.06, 0.06, 4.6)
180 conv_table(4) = Array(4.64, 4.64, 0.06, 4.64)
190 conv_table(5) = Array(4.6, 4.6, 0.06, 0.06)
200 conv_table(6) = Array(4.64, 4.64, 4.64, 0.06)
210 conv_table(7) = Array(2.36, 4.62, 4.6, 0.06)
220 conv_table(8) = Array(2.38, 4.66, 4.66, 4.66)
230 conv_table(9) = Array(3.2, 3.2, 4.66, 4.64)
240 conv_table(10) = Array(4.66, 2.38, 4.66, 4.66)
250 conv_table(11) = Array(4.66, 3.18, 3.2, 4.64)
260 conv_table(12) = Array(4.66, 4.66, 2.38, 4.66)
270 conv_table(13) = Array(4.66, 4.66, 3.18, 3.18)
280 conv_table(14) = Array(4.66, 4.66, 4.66, 2.38)
290 conv_table(15) = Array(0.06, 4.62, 4.62, 2.34)

 

[Michael McSharry]

The 3.6 volt readings are not within any range that will result in a valid direction. It is not as simple as a low voltage as no 0,x,x,0 pattern is valid. It would take so analysis of the resistor network to see how you can get such readings, but it does point to something at the sensor.

 

[ksdehoff]

Michael:

I'm pretty convinced it is the AAG device ;(

I isolated it to its own 1wire environment and took it off the roof to test so I could control the wind vane. at the 8 points of the compass I got 2.5, 2.5, 2.5, 2.5, 0.02, 0.02, 0.02, 0.02 as I rotated clockwise. Is there some foolproof method to test the ds2450?

Thanks
Ken

The 3.6 volt readings are not within any range that will result in a valid direction. It is not as simple as a low voltage as no 0,x,x,0 pattern is valid. It would take so analysis of the resistor network to see how you can get such readings, but it does point to something at the sensor.

 

[Michael McSharry]

It is very unlikely the solid state DS2450 is defective, but the input network has several opportunities. You can check the input voltage which should be 5V

 

[ksdehoff]

So:

Good news first is that I can make the instrument work. With my USB dongle and mcs 1wire v 2.75 its working. This isnt my live configuration though. When I connect the wind instrument to my powered serial 1wire hub, it doesn't work. Would the hub have something to do with the problem?

Thanks
Ken