I'm looking to build a distributed PLC system with up to 20 devices spread throughout a building, controlling lights, HVAC, irrigation, security, etc, and want recommendations on what connector to use for CAN and DC power.
The power (24VDC, 1W/device max, 50mW/device typical) and CAN will go in the same cable. While M12 connectors seem to be "common" for CAN, they're not very easy or cheap to buy.
RJ-45 looks like the all-around cheapest option and the quickest to terminate cables, but I'm concerned about reliability and power handling with 20-40 plug/socket pairs in series, before you even consider copper loss and unclean/non-office environmentals like heavy dust and insects. I could use two pairs for power to improve matters but it's still marginal.
I could use Molex or Camden style power connectors but they have other issues, like the time taken to terminate cables and increased likelihood of transposed conductors.
What standard connector, perhaps commonly used for building management and/or industrial automation, am I missing? I don't need 1Mbps; 100-200kbps should be plenty so impedance control isn't real important.
Background: I would like to avoid a star topology and the central switch or controller that it implies. Running one CAN cable adjacent with the power distribution cables also reduces the installation cost dramatically, especially for retrofits.
Edit: does anyone know what is used in vehicles? They'd have to be plentiful and reliable.
Best Answer
CAN In Automation recommends 9 pin D-sub connectors with a specific pinout. These aren't easy to get two wires into each pin for daisy chaining, so you might need to use a field rewirable type like this Phoenix Variosub rewirable D-Sub Connectors.