DDC Advice?

Hello all, After posting a thread about my hot water solar control dilemma, some of you mentioned a DDC instead of a PLC because of the simplicity of what I am trying to control: a few sensors and valves and a circulating pump all controlled by temperature readings and differentials. As far as DDC's go I am lost, can anyone point me in the direction of a very basic (and hopefully reasonably priced) DDC and where to get it? I am not trying to automate a building here just control a solar setup. Thanks in advance for any help!

Web Forums usually have people who give an opinion - problem here is it's PLC's not DDC's.

You might try a Google search for DDC HVAC forum

here are some of the hits:

forum:
http://hvac-talk.com/vbb/showthread.php?t=259342

forum:
http://www.hvacprotech.com/viewforum.php?f=45

How DDC operates:
http://www.achrnews.com/copyright/BNP_GUID_9-5-2006_A_10000000000000481563?view=print

Good DDC overview site:
http://highperformancehvac.com/Building-Automation-Systems/Direct-Digital-Control/HVAC-Control.html

Dan