SN65HVD255: TI CAN solution for 50kbps and long distance 400m+

Hello Kyt,

Thank you for the question.  Just to clarify, the Turbo CAN function on the SN65HVD255 allows the device to operate at higher speeds, which would hurt your performance over such a distance as 400-1000m.

Your main concern over this distance will be the round trip propagation delay of the network.  Each node will need to know the round trip delay so that it is programmed with an appropriate data sample point that accommodates the worst-case delay in the network.  A general rule of thumb for cable delays in a CAN network is 5ns/m of cable.  For your request, 1000m of cable could provide an extra 5us or more of delay, which reduces your maximum operating speed to <100kbps.  Operating at 50kbps should be fine, but you will want to pay attention to any extra delays added into the system by extra nodes, isolation devices, etc.  

You will also want to note that your minimum operating speed is determined by the CAN Dominant Time Out (DTO) of the device, which normally constrains the minimum speed to 10kbps, as in the SN65HVD255.

Is there any reason why you are looking at the SN65HVD255 specifically?  If you are operating at 5V MCU levels, you may want to consider the TCAN1042 or TCAN1051 for your application as well.  

Please let me know if you need any further clarification or if there are other delays introduced into your application network that may be pertinent to the discussion.  

Best Regards,

Max Megee