I love the M12 connectors, but they are expensive and dealing with CAN or RS485 I often find myself in need of screw terminals or D-SUB 9 rather than point to point expensice M12 connectors and cables. One example is the module below which is a RS485 with M12-5. It is great for what it is, but screw terminals would be easier except for the waterproof issue.
I could provide a DSUB-9 version, but the solution I used on the 3 x CAN hub (below) is low cost and can be adapted to DSUB9, Screw terminals or even M12 with a bit of trickery. But, the M12 design is unique in the sence that it allows 8 x sub-modules to be plug & play on a waterproof design. Also – on the new ECUMain I used NMEA2000 power connector with integrated CAN. NMEA2000 is designed for boats, but theire cable design is well suited for vehicles in general that need waterproof modules. Also the point to point cabling standard is a strong argument.
The cost argument on M12’s is less important if you need an IP67 or similar standard, but it add ca 100 USD in cost on a 6 x CAN versus the alternative, so I might need to design two connector versions or find a compromise with adapters. I will correct my 100USD bill a bit – if I order M12’s from low cost Asian source they cost 5.- USD each with a total cost of 30:_ USD. If I order the same from an European distributor I end up with 25.- USD a peace giving a comparable cost of 150.- USD – that is a big difference.
M12 based cabling is not cheap either, but here I can argue that dong manual cabling cost far more and open for far more maintenance issues. Also – one of the arguments for a M12 was lower assembly cost in total – I actually can expect end users to assemble their own little mini PLC in a waterproof box with the M12 design.
One lesson I have learned from participiation in two EV projects are to address size,cost, waterproofness and shock absorbation – which the M12/MX23 design actually do. Any attempt on using more classic PLC solution on a vehicle will result in added maintenance costs later.
The solution might very well be that I need two connector designs on everything – one for desctop/cabinets and one for vehichles.