I have two main questions regarding the electromagnetic compatibility (EMC).
If I develop an electronical device and market it in Europe, it needs to be EMC-compliant, right? How come I can buy European devices which are not EMC-compliant? Do the devices truly need to pass the EMC test to be certified?
Let's say I have to develop a system with a microcontroller which retrieves data from a sensor. The sensor is outside of the PCB, and I have to use a wired communication between them. For instance, temperature sensors are usually accessed through I2C. However, transmitting I2C through a cable will not pass the EMC (and maybe not even work if the cable is too long). I can use an I2C buffer to make it work but still it will not pass the EMC. Is it necessary to convert the data to another protocol (RS485, RS422, RS232, CAN...)? Does it mean that each external sensor would need its own microcontroller? I find it a bit onerous, are there other solutions?