Mike said:
Could you describe the intended function please? It seems you use another device or controller to display data on an LCD and to perhaps setup or edit the 'zone' temperature set points.
Does this unit monitor up to eight 'zone' temperature sensors and simply drive relays at the correct setpoints?
Its intended function was to connect to a multistage Heater / Air Conditioner. RS485 sensors (like the Cricket or the unreleased very simple Moth).
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Although it has only eight relays more (a typical single stage HVAC will use three Heat/Cool/Fan) you can use the remaining relays to control dampers. As an added bonus the new Cricket pro supports a single relay (more can be added with the EXP connector) You could control heated floors or vents with the single local relay. A high-end Aprilaire 8870 for example has 6 relays and an RS422 port.
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Ideally, one or more Ladybugs can control many (32 or more) Crickets at a distance up to 4000' or other RS485 devices; while the RS232 port be controlled by a small HA server or Ethernet to RS232 bridge.
Of course you can program it to be much more (or less) than that.
With the right software (I'd like to keep it as open as possible) you could easily emulate something similar to an ELK Magic MM443 **broken link removed**
How about an ADI Ocelot
http://www.appdig.com/adicon_new/ocelot.htm
Or link it up to a small linux box (I use this for my web server/router etc..)
http://www.clarkconnect.com/
and make a really-really powerful version of a JDS Stargate-IP
http://www.jdstechnologies.com/
It can also act as a RS485 to RS232 bridge. Or 1-Wire bridge (1-wire stuff is amazing) Or even just a simple relay board.
As a bonus the Cricket (Thermostat) & Ladybug (Controller / Relays) are ICD2 (Inchworm) ready.
I'm working on PCB layouts for a 16F876A Inchworm, Cricket & Ladybug.