Since several months have passed, I was curious about what you (or others here) ultimately chose? I too am looking for something to interface “traditional” switches and buttons.
My priorities include:
- Low latency
- Ease of long-term maintenance
- Some short of shielding/isolation between said I/O and Ethernet (or other interface)
- OH2 integration
To achieve this, I am willing to pull wires wherever this helps. My ducts don’t have room to pull all the existing light switch wires to a single central location. However, as thinner cabling is used for the signal-only wires, I should be able to have all wires converge to only two locations. These already have DIN rails, a separate low-voltage area and Ethernet.
I too did consider a set of small distributed KNX or (Z-Wave or ZigBee) I/O boxes, but that is ending up to be quite expensive, and I am not sure about the maintenance in all those different places, one or more decades from now.
So right now I am increasingly looking at something like the Moxa ioLogik E1210 (description, PDF), which has 16 inputs for $185 (price from industrialnetworking.com).