I'm looking to build most of this myself.
A. for experience and
B. if successful implement it

This is a 2 part project first part is I would like to Monitor water temps
of a closed loop solar hot water system there will be a few pumps and
a few valves including temp sensors through out the system.

Part 2 is Monitoring 3 zones of air allowing me to open/shut zone valves
to heat/cool what ever zone is calling for it.

I know there are devices I can buy that will already do this for me
but i'm more in it for the fun of building the system myself.

I was thinking of using analog to digital converters over the RS-232
not sure if I should use the RS-232 for relay switching tho and I do not know at this point how many input and out put channels I need just yet.
And lastly the program that will control/Monitor it all with be labview.

Thanks in advance and I hope I put this in the right part of the forum.

 

Now that I think about it should I use the LPT port instead?

 

I might suggest you are getting a bit ahead of yourself. Think first of what temperature sensors to use, how many of them need to be switched to the A to D converter, what level of resolution will you need, and so on.

If you are planning to use a stand-alone A to D converter, how will you synchronize the input switching, and how will the receiver know which sensor output is being sent?

 

Was thinking of going with this sensor
http://www.automated1.com/datasheets/DS_ATS2000A.pdf

So looks like I would need 8Bit ADC and I think ill need about 6
not sure how many relays i need just yet.