Author Topic: TxWx WR-25 - splitting rs232 between two pcs - HELP!  (Read 778 times)

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Offline longmire

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TxWx WR-25 - splitting rs232 between two pcs - HELP!
« on: August 14, 2022, 01:18:46 PM »
what I want to do:

PC1 - VWS ------------PC2 - WD
                        |
                   WR-25

I have a passive RS232 splitter (Blackbox Code: FA151a DB-9 Tap) ANd I know the WR-25 needs a null modem cable to connect to PC1 (which is what I have now). PC2 is running WD and I'd like the WR-25 to feed both over the RS232 splitter. SO if i connect the wr25 using the null modem cable to the blackbos tap, should i connect the tap to each pc using a straight thru cable or do I need null modem cabled from each pc and a staright through to the wr25?

This all is because I cannot upgrade the OS in pc1 to win 10 (i would lose the ability for VWSQL to keep running) and I want to use WD to also collect the data since it is still being delveloped and supported.

Don't everyone jump in on this at once hehe!  ](*,) [tup]

Steve

Offline DaleReid

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Re: TxWx WR-25 - splitting rs232 between two pcs - HELP!
« Reply #1 on: August 14, 2022, 01:37:46 PM »
I haven't looked at any transmission FROM the computer via code from WD or if the WR-25 runs in a mode sending output strings continuously.

If I recall the code for the TWI drivers from WeeWx actually send a command to transmit, and depending upon C or R or some other command, the weather station sends out the required string or single value.

Have you looked to see if this is what is going on?  Have you put the serial output from the station into a pc running either PuTTY or TerraTerm to see if there is something coming all the time?
Dale

PS, IF you get it to work as you want, please share how you did it. 
ECWx.info
&
ECWx.info/t/index.php

Offline longmire

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Re: TxWx WR-25 - splitting rs232 between two pcs - HELP!
« Reply #2 on: August 14, 2022, 01:53:58 PM »
Dale - at present VWS is the data collection software. And I have not tried either PuTTY nor TerraTerm to see whether VWS is sending rapid streams of C or R to the wr-25. This is of course a key point if I want to share the 232 line without son=me kind of datalogger interposed.

Right now I have VWS set to generate a csv file every 2 sec on pc1 and then wd reads this from there (on PC2 over the same LAN). This of course introduces delays along the path, but produces output on WD that is at least as near time as rapid fire ever was.

Pardon my ignorance of Putty or others, but I I were to install this on PC1 (VWS Win 7), would I be able to have PuTTY "spy" on the serial com while VWS chats with WR25? Is that how this would work? I would be very grateful for any guidance with this - as I try very hard not to change anything in the Win 7 (VWS PC1) machine since almost everything on it is past its EOL date. Its the only machine on the LAN that gets daily full backups and every 3 hour robocopy mirrors (belt, suspenders, and a rope here!)

Steve

Offline davidefa

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Re: TxWx WR-25 - splitting rs232 between two pcs - HELP!
« Reply #3 on: August 14, 2022, 03:44:40 PM »
Not sure the 'FA151a DB-9 Tap' can do what you want to do.
If the communication between wr-25 and pc is 'monodirectional' without hardware handshake, it should work
If the communication between wr-25 and pc is 'monodirectional' with hardware handshake, it may work
If the communication between wr-25 and pc is bidirectional, it won't work ( as you'll end up shorting the two pc com ports output lines )

Offline longmire

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Re: TxWx WR-25 - splitting rs232 between two pcs - HELP!
« Reply #4 on: August 14, 2022, 04:14:00 PM »
That's what I was afraid the case would be, David. Sadly, since the wr-25 is out of production and the whole development crew now out of contact, those of us with these long-lasting old machines are left to our sleuthing and tinkering skills to divulge their communications secrets.

Once you throw two completely different software apps into the mix - it becomes an even larger challenge. I have heard of a software-based approach that virtualizes the physical com ports - but that would require running WD and VWS on the same (old) win 7 machine - and the risk that it will one day just not work anymore.