>Good thoughts Lutz and Al. Thanks.
>
>I'm ok with backing off on the process side, but I'm still interested in monitoring some temperatures, and displaying an ongoing status for them on my running VFP business program. The answer to this might be in your link Al, but my question now shifts to how do I capture those temperature readings (and I'm still interested in doing this capture without a real PLC in the picture) if the existing process is in place without a PLC. For a sample problem, I'd just like to know how to wire something up, to get an outside temperature to display on my VFP screen in my house. I'll be going through the provided Bastian link (and where it takes me) tomorrow.
>
>Bob

Bob,

So you like to do the PLC control and monitoring / supervision on a PC

If you do this asynchronous (The PLC can store records and the PC pulls them later) monitoring could be o.k.
control -> as others point out a PC is much to vulnerable.

I still prefer to have to PLC on its own (without uplink).
:)