to E-Ryc:
osobně dávám přednost CAN-busu před RS485 a RS422:
RS-422 and RS-485 are communication standards designed for differential data transmission in noisy environments. While they share similarities, their differences make them suitable for distinct applications.
RS-422 is a unidirectional, multidrop standard that supports one driver and up to 10 receivers. It is ideal for simplex communication where data flows in one direction. RS-485, on the other hand, is a bidirectional, multipoint standard that allows multiple drivers and receivers on the same bus, making it suitable for half-duplex communication.
RS-422 drivers are designed for lower current loads, supporting up to 10 receivers with a single termination resistor. RS-485 drivers are more robust, capable of driving up to 32 unit loads (ULs) with two termination resistors. This makes RS-485 better suited for applications requiring higher receiver counts or longer cable lengths.
RS-485 offers a wider common-mode voltage range (-7V to +12V) compared to RS-422 (0.25V to 6V). This allows RS-485 to handle larger ground potential differences, making it more reliable in industrial environments.
RS-485 includes protection mechanisms like short-circuit current limiting and thermal shutdown to prevent damage during bus contention. RS-422 lacks these features, as it is not designed for multipoint applications.
RS-485 components are backward-compatible with RS-422 systems, but RS-422 components cannot be used in RS-485 networks due to their limited drive capability and lack of contention protection.
In summary, RS-422 is best for simpler, unidirectional communication with fewer receivers, while RS-485 excels in complex, multipoint, and bidirectional systems.
CAN bus je totiž výrazně rychlejší, umožňuje připojit více jednotek a hardwarově vyjde nastejno.