Hi,

I don't know.  I don't have one.  Presumably an approximation can be got 
from http://www.sydneystormcity.com/people.htm

Cheers

Ian

Angel wrote:
> Hello Ian,
>
> Just to get an idea,  how many PSN-ADC-SERIAL Version II with GPS timing and full time internet connection are there out there.
>
> I have one.
>
> Angel
>
> Saturday, January 5, 2008, 3:57:40 PM, you wrote:
>
>   
>> Hi,
>>     
>
>   
>> yes, you're right, all free.  I was really addressing the earlier 
>> (possibly hypothetical) question of how to connect many sensors to 1 
>> network connection.  The engineer in me probably made my response a bit
>> enthusiastic and suitable for connecting dozens of sensors.
>>     
>
>   
>> Back to (free) reality!
>>     
>
>   
>> Cheers
>>     
>
>   
>> Ian
>> http://www.iasmith.com/
>> http://www.festivalpreviews.com
>>     
>
>   
>> Angel wrote:
>>     
>>> Hello Ian,
>>>       
>
>   
>>> I have not read each messages of this thread careful but I will. All of the software needed to link a large distributed seismic system is free and freely available.
>>>       
>
>   
>>> Anyone who has one of Larry's 16 bit 8 channel boards with GPS (wwv) timing and a full time internet connection can share data and PSN can a global or regional system auto locating system.  
>>>       
>
>   
>>> Angel
>>>       
>
>
>
>   
>>> Saturday, January 5, 2008, 9:35:41 AM, you wrote:
>>>       
>
>   
>>>   
>>>       
>>>> Hi,
>>>>     
>>>>         
>
>   
>>>   
>>>       
>>>> actually, I don't think I'm near any limits.  The A/D I use can handle
>>>> 20K samples/sec.  I only have 2 instruments (though I sample each on 3
>>>> A/D channels to get the resolution up to 22 bits), so that's only 6 x 
>>>> 50, or 300 samples/sec.  So I could connect up all of the A/D's 16 input
>>>> channels and still not stress it.
>>>>     
>>>>         
>
>   
>>>   
>>>       
>>>> The data server does burn up 80% of the PC's CPU but it's only an old 
>>>> 800 MHz machine and wouldn't cost much to replace with one twice the 
>>>> speed.  Data across the network connection is only 32 characters x 50 or
>>>> 1600 bytes/sec.  Less than a 500th of the 100 Mb/s network bandwidth 
>>>> (being generous).
>>>>     
>>>>         
>
>   
>>>   
>>>       
>>>> All of the above though, implies that you are happy to write your own 
>>>> code.  Buying building blocks off the shelf can be very attractive. For
>>>> multiple instruments you could buy several PSN A/D boards.  To overcome
>>>> the potential problem of connecting up multiple RS232 cables, you could
>>>> use a network terminal server (such as 
>>>> http://www.perle.com/products/IOLAN-STS-Terminal-Server.shtml?rack ).
>>>> These aggregate up to 4/8/16/24 rs232 connections on to one network 
>>>> connection.  They usually come with software for the pc which creates 
>>>> multiple virtual COM ports, so your A/D boards would look like they are
>>>> plugged into an array of COM ports on the PC.
>>>>     
>>>>         
>
>   
>>>   
>>>       
>>>> Isn't technology wonderful!
>>>>     
>>>>         
>
>   
>>>   
>>>       
>>>> Cheers
>>>>     
>>>>         
>
>   
>>>   
>>>       
>>>> Ian
>>>>     
>>>>         
>
>   
>>>   
>>>       
>>>> ChrisAtUpw@....... wrote:
>>>>     
>>>>         
>>>>> In a message dated 04/01/2008, gpayton880@....... writes:
>>>>>       
>>>>>           
>
>   
>>>   
>>>       
>>>>>     But rather than have 1 sensor on a single socket it is more
>>>>>     sensible to
>>>>>     have many sensors on a single socket using a data protocol.  This
>>>>>     is how
>>>>>     I have designed my system.  It sends out a continuous stream (50
>>>>>     samples
>>>>>     per second) of "(Lehman reading) (geophone reading) (time
>>>>>     stamp)".  My
>>>>>     graphing program makes a connection to the "data server" and plots
>>>>>     the
>>>>>     values from the 2 sensors as they arrive.  See
>>>>>     http://www.iasmith.com .
>>>>>       
>>>>>           
>
>   
>>>   
>>>       
>>>>> Hi Ian,
>>>>>  
>>>>>     The limitation tends to be the total data throughput 
>>>>> speed reqired. 50 SPS is quite fast. The ADC sample rate can also 
>>>>> impose limitations. This starts to become serious when you have, say 
>>>>> several three off three channel sensors on the same ADC.
>>>>>  
>>>>>     Regards,
>>>>>  
>>>>>     Chris Chapman
>>>>>       
>>>>>           
>
>
>
>
>   
>>>   
>>>       
>
>
>
>
>   

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