davis vantage pro weather sensor

[overmind]

hello everybody.. i have a davis vantage pro weather station. this weather sensor has a sensor that gathers all the parameters and a separate console that displays the data. the sensor and the console is communicates via rs485. what i want to do is connect the sensor directly to my computer and do some manipulation on the data it gathers. it seems that the console doesnt send anything. it is the sensor the sends data every 3 seconds and the console just receives the data. however, when i try to sniff the data from sensor using an rs485-rs232 converter, it only repeatedly outputs these data "fxxf". can anybody help me as to why these happen? or has anyone in here successfully get the data directly from a davis weather station? please help.. thanks in advance

 

[blueroomelectronics]

Some RS485 devices use an extra bit in the transmission for address vs data, your terminal program probably doesn't support this mode.

 

[overmind]

hi thanks for the reply.. the weather station uses ADM3485E while my rs485-rs232 converter uses max3440e. am i missing something cause i cant seem to find in its data sheet that it uses an extra bit to send data. please help.. thanks in advance..

 

[3v0]

The chips you mentioned are transceivers chips. More then a level shifter but no understanding of the data they send and receive. Bill is talking about the data format is determined by the microcontroller or whatever on the other side of these chips.

uC <->transceiver <-> rs485

The documention for the data format might be found on articles about hacking the station.

 

[overmind]

hi.. thanks for the reply.. can anybody show me links on how to solve my problem.. (how to hack the vantage pro station) m sorry but i tried to search the net for the past three hours but still was unsuccessful in finding the kind of data format used by the weather station. please help.. thanks for your continued support..

 

[3v0]

Going back to what Bll/Blueroom was saying. What terminal program are you using to sniff the data. Are you looking at it as ASCII scharacters or hex data and how many bits.

You should be looking at it as hex. Figure out if it uses that 9th bit etc.

FxxF could be a valid ASCII representation of valid hex data.

I use 1 wire sensors for this sort of thing. They are well documented and easy to use. What sensors do you have ?

 

[overmind]

hello.. im using the hyperterminal to sniff the output.. m using baud rate = 9600, data bits=8, parity=none,stop bits=1,handshake=1. the sensors are from the davies vantage pro2. instead of it being connected to a console, i try to sniff it and send its data directly to the pc.. please help.. thanks

 

[3v0]

hello.. im using the hyperterminal to sniff the output.. m using baud rate = 9600, data bits=8, parity=none,stop bits=1,handshake=1. the sensors are from the davies vantage pro2. instead of it being connected to a console, i try to sniff it and send its data directly to the pc.. please help.. thanks

Hyperterm is the wrong tool. You needd to use one that will show you the bits and bytes not ASCII characters.

There are a few out there. It has been a while since I used one and do not recall which. This is the first hit "rs232 analyzer software". Have not used it. Not sure of the limits on the FREE version but there is no time limit.

232Analyzer is an advanced serial port protocol analyzer software that allows programmers, engineers, and others to control, monitor and analyze serial port (RS232 / RS485 / RS422 / TTL, etc.) activities.

You need to understand it will just show you a bunch of data with no indication of what it is. Some of it may be discovered by changing the sensor input.

As I said earlier. If this is over your head you may want to look at 1-wire/ ibutton sensors. It is a well documented interface and there are many code examples in both C and Basic.

3v0

 

[ericgibbs]

hello.. im using the hyperterminal to sniff the output.. m using baud rate = 9600, data bits=8, parity=none,stop bits=1,handshake=1. the sensors are from the davies vantage pro2. instead of it being connected to a console, i try to sniff it and send its data directly to the pc.. please help.. thanks

hi.
Look at this link, suggests not compatible with standard RS232.

Vantage Pro FAQ Answers Section 6 [Prodata Weather Systems]

 

[kiteman]

Hi,
someone managed to read the data on the rs485 from sensors of davis vantage pro?
I built a converter with the max485 but the serial data I get are different than overmind.
I think baud rate is 4800
But I dont see a data

 

[kiteman]

hi.
Look at this link, suggests not compatible with standard RS232.

Vantage Pro FAQ Answers Section 6 [Prodata Weather Systems]

Hi,
your link does't work. I receive serial data string from rs 485 but the problem is to estract all datas

 

[crl]

I am interested in this topics.

Did you find a solution? Could you post a feed back concerning you results ?

Regards CRL